Officina Stellare RC360 Pro ... has arrived!!

[marc4darkskies]

My wife Gail and I drove down to Melbourne to Astronomy Alive yesterday to pick up my new arrival.

Here are some happy snaps (Pbase images have the commentary at the bottom (they are small 250k-ish downloads at "Original" size)). There will be plenty more (of course) ... after I recover!

http://www.pbase.com/gailmarc/officina_stellare_rc360

Many thanks to Cris at Astronomy Alive for his help and guidance throughout the process since February.

Cheers, Marcus

[gregbradley]

Awesome Marcus.

First light can't be too far away now.

Greg.

[Astroman]

Just in time for the cloud to disappear.. :)

[strongmanmike]

Love it :lol: I will be watching the beauty go up with much excitement mate, hope all goes smoothly for you :thumbsup:

Oh and sorry I wasn't there to help :ashamed: :ashamed:

Mike
juuust a wee bit jealous

[Kunama]

Nice little "Grab&Go" setup Marcus, I suggest a Vixen Porta Mount II.

[Logieberra]

Looks super secure and well packaged. You must own a truck to move that item!

[Hans Tucker]

Did you get that New Telescope smell when you opened the box :D.

Either way it looks a beauty...can't wait to read your first light reports

[marc4darkskies]

Thanks guys - yes, it's starting to get real now!!:help: It's daunting though - lots to do and test to commission this beast. I fully expect some hurdles, but looking forward to the end result.

So ... I had enough energy left today to open some boxes. The scope is still in the crate but those boxes were calling out to me.

Attached is the teaser. Other photos and commentary on the PBase site. http://www.pbase.com/gailmarc/gallery/officina_stellare_rc360

[h0ughy]

lovely looking machine, and that grinning owner

[FlashDrive]

Awesome Scope Marcus......now you can ' adjust ' your signature ....;)
Will love to see your first ' pic's ' .....watch this space eh....!

:thumbsup:

[RickS]

Congrats, Marcus! Look forward to some images.

[Larryp]

Congratulations-lovely scope!

[DavidU]

Awesome ! You will do well with that.:thumbsup:

[marc4darkskies]

Jealous??! Nothing to be jealous about mate! Nothing at all ... untill I get it working!! :D:lol: Funny, Gail and I both mentioned your name in unison as we stood in the stifling heat after a very long drive watching a few bobs worth of scope sit there smugly challenging us to lift it out of the car without dropping it. :scared: I'm glad Gail is stronger than she looks!! :)

Apologies in advance to those thinking first light is near, forget it!! :eyepop: Bench testing, mount wiring, mounting, collimation, TPoint modelling and some head scratching will likely take many weeks.

I do plan to make this thread a bit of an ongoing review of everything about this scope and its commissioning ... warts and all. I'll include lots of pics too.

Very much appreciate your interest & good wishes guys!:thanx:

Cheers, Marcus

[strongmanmike]

Ah I have faith, you are a rather capable lad ;)...if it were me..:question:...:driving: :juggle: :help2:

[DavidNg]

Wow, congratulation. Are you going to fit that huge scope inside the 2.3m Sirius?

[Bassnut]

Excellent Marcus, very cool. Cant wait for 1st light.

[Joshua Bunn]

Way cool Marcus, looking fabulous.

[Astroman]

So is it on the mount yet? itching for those pics....

[marc4darkskies]

Hehe ... yes, we're nearly there! ;) I would like to get it out of the crate first though.:question:

[marc4darkskies]

A bit more heavy lifting as I extracted the scope from its crate.

Other photos and commentary on the PBase site. http://www.pbase.com/gailmarc/galler...stellare_rc360 (http://www.pbase.com/gailmarc/gallery/officina_stellare_rc360)

[renormalised]

Gail: "I'm glad you like my knick-knacks. But the one that's got pride of place is Marcus's antique electric drill. He got that from his g-g-g grandfather. It's worth quite a lot!!!" :) :P :P

Mormon Nuisance: "Oh"

:) :P

Nice scope, Marcus :)

[David Fitz-Henr]

You're not serious Marcus??? Far too precious an item to take out of the crate; I suggest that you cut a hole in the end of the crate and screw the dovetail saddle to the crate bottom :P :lol::lol:

Just looking at your pics, the one with the scope on a flimsy little table looks a little iffy - will you be using that for all your bench testing? :screwy::scared: (I don't like the look of that guy standing next to it either...)

[stevous67]

The OS RC360 is a piece of art. Very nice Marcus.

Steve :bowdown:

[Paul Haese]

Beautiful looking scope Marcus. I am sure you will produce some amazing images from the new system. The crates and packaging looks very good. Best of luck and I look forward to the images.

[marc4darkskies]

Don't worry David, the table's rated capacity is 20kg but we all know that small tables are rated to hold lamps, plates & cups, not telescopes, so the table's capacity spec can safely be ignored. :P Also, it’s only a little bit wobbly!!!



Thanks Paul.

[gregbradley]

That is a beautifully crafted looking scope. Lots of nice touches there.

Greg.

[Phil Hart]

Exciting! That's some new toy :eyepop:

Phil

[strongmanmike]

Hey Marcus, I found your lost ping pong ball there too...it's next to the 8" dob :thumbsup:

[Astromelb]

Dear Marcus,

It has been a pleasure to assist you with the system. Plus is was also a nice opportunity to meet you face to face.

I know you are going to do this system serious justice with your imaging, and look forward to the opportunity to pass your images back to Officina Stellare for them to proudly display on their webpage and Facebook page.

Officina Stellare are a very very proud supplier, and I am delighted that everything has worked out so well. I will pass your "complimenti" on to them and copy them with this thread, as they really get a lot out of customers responding to their efforts.

Now all you need is time, patience in the commissioning phase, and then finally ...... some darkness :)

Rgds,
Cris Ellis.
Astronomy Alive.
(Astromelb)

[Peter.M]

Yes but is that 20kg for imaging? "Consider these as guidelines since some telescopes are physically long for their weight or have very long effective focal lengths and may require a larger table." :lol:

Seriously cool piece of gear!

[issdaol]

Impressive kit there Marcus. If you don't have dark enough skies you are welcome to park it on my new property permanently :-) he he he

[lazjen]

That is a very nice looking piece of gear. Very cool. :)

[marc4darkskies]

Work tends to get in the way of playing with new toys :mad2: so this is just a minor progress report - no new pics yet. But in the spirit of sharing the journey ...

So far I've sat and stared, enjoyed the new scope smell and played with the pretty laser! :D There is no manual yet so it's a process of discovery. Thankfully, OS tells me that a manual is forthcoming soon and they've been very responsive to my email queries, responding overnight.

On top of basic familiarisation, I've only figured out my cabling & peak power requirements at this point and roughly how to laser collimate (in theory at least)

Cabling:


OTA: Cat 5 serial plus 12V supply - cables supplied
Pyxis rotator: RJ12 serial port and no cable supplied (this is deliberate on the part of the manufacturer :shrug:) plus 12V supply
Atlas focusser: USB plus 12V supply - cables supplied

Peak Power.


The OTA - 2 heaters, 3 fans, a control unit (ATC-02) and a secondary focusser - 5 Amps
Pyxis - 1A
Atlas – 1A
Camera – 3A

I'll have to upgrade power through the mount to a RigRunner (fused 12V power distribution board). A 12AWG cable should be enough I think. I've already got USB and serial through the mount.

I also found out that the imaging train adaptor has a push pull setup to be able to correct for non-orthogonality (if required) later on. Nice touch. (see picture of the back of the scope – 3 sets of 2 screws on the flange of the adaptor)

The fun stuff will start this weekend:


Laser collimate
Install ATC software
Power up the OTA and establish PC to OTA comms
Make the Pyxis serial cable
Install rotator and focusser software
Install the optical train
Establish comms with the rotator and focusser

Doubt I'll get all this done but I'll make a start. Fingers crossed not too many hiccups! :prey: The trick with all of this is to take your time to understand what you have to do before you try to do it - slow and steady!

Cheers, Marcus

[allan gould]

Enjoy every moment of the journey. A beautiful scope indeed Marcus.

[UniPol]

How much has this outfit cost you Marcus as I am thinking of purchasing one as well ? I see OPT are selling OS and the shipping costs seem pretty reasonable.

[marc4darkskies]

Cheers Allan!



Frankly, I wouldn't even dream of buying from Opt. Cris at Astronomy Alive treated me very well and has an excellent relationship with Gino at OS. I'd suggest you give him a call before you consider importing yourself. I got the bells and whistles version and it's safe to say it was significantly cheaper than an equivalent RCOS + extras would have been (had they not gone out of business)

[marc4darkskies]

Did a collimation check this morning. Out of the box it looks like no adjustment is needed - see attached (and commentary under the PBase version). I find this astonishing and a testament to the quality of crating and packaging.

A few new images also on PBase:
http://www.pbase.com/gailmarc/gallery/officina_stellare_rc360

[gregbradley]

That is very good. My CDK did not need adjustment either. That's a pretty cool laser tool you have there. Who makes that? Does it only work on RC designs?

How is the baffling on the scope? It looks really well made. My only criticism of the CDK17 is the baffling was not well done and they fixed it on a rolling basis for free which was good. In fact Rock sent me a new baffle for the primary mirror just a few weeks ago after I discussed it with him at AAIC. Good service.

Does OS sell a reducer for this scope? Chances are your Tak super reducer would work with your STL11. I used a 2.7 inch Tak .75X reducer on an RCOS 12.5 and it mostly worked (corners were not 100%).

Greg.

[marc4darkskies]

It looks like a Howie Glatter - see attached pic. It would work on any scope I think.



The primary baffle has 4 internal baffles



I don't think they do sell a reducer - I might ask. I'm not really interested right now anyway.

[Occulta]

Beautiful 'scope Marcus.
Just don't leave the laser on too long :eyepop:

[marc4darkskies]

:lol: ... nice one Chris!

[marc4darkskies]

Okay, I've installed the ATC-02 telescope control software & set up for bench testing. I powered up the scope and connected to the PC. Fans & heaters work, secondary focusser works and environment variables are being measured. Spiffy interface too! So far so good. Just need to I make up the RS-232 cable for the Pyxis now, then I can test everything.

More pics & commentary at http://www.pbase.com/gailmarc/gallery/officina_stellare_rc360 as usual.

[Occulta]

:thumbsup:

[Bassnut]

wow, thats all looking very smick indeed Marcus. I like the scope controler, humidity control is a nice touch. Interesting heating is automated, but not cooling, as in auto fan control?.

[Paul Haese]

Awesome Marcus. That laser collimator, I take it that is one by OS? Looks very good.

[Peter.M]

I take it the ribbon cable to the secondary focuser is in line with the bottom vein and that is why it is slightly wider than the other shadows?

[marc4darkskies]

Cheers Fred. Interesting point, fans are manually controlled. I guess once the fans have hastened equilibration - their only purpose really - they're not needed. Could they be turned off when temps have equalised? Dunno, this is new territory for me. The nice thing about measuring humidity is that the heaters will keep the mirrors at the selected threshold above the dew point, not ambient. So, if the dew point is way below ambient they won't be turned on.



Cheers Paul. Yes, supplied by OS.



Correct. I'm trusting this has no noticeable impact on diffraction spikes. It worth noting that the veins are very thin - 1.6mm. Also, the ribbon cable is flocked so that adds to thickness.

[gregbradley]

[QUOTE=marc4darkskies;1034112]Cheers Fred. Interesting point, fans are manually controlled. I guess once the fans have hastened equilibration - their only purpose really - they're not needed. Could they be turned off when temps have equalised? Dunno, this is new territory for me. The nice thing about measuring humidity is that the heaters will keep the mirrors at the selected threshold above the dew point, not ambient. So, if the dew point is way below ambient they won't be turned on.


I have gotten dew on the mirrors of the CDK17 about 3 times in 3 years. Its not really a problem. As far as auto when it hits ambient that is also a nonissue as the mirror always seems to be a tad above ambient and the closest is .1C difference I have seen. Maybe once in a blue moon it goes below ambient. That is more ideal anyway as you don't want a boundary layer on the top of the mirror.

Talk to Paul Hease or Bird about thermal effects on mirrors. They cool theirs to get it below ambient a few degrees to get rid of thermal currents.

Ideally there should be fans blowing across the mirror. The latest CDK17 has this. Mine does not. It gets rid of the boundary layer. I was thinking of rigging up some fans facing across the mirror. 2 should do it.
Ron Wodaski talked about thermal currents and sideways fans at AIC this year.

Auto dew heating could be handy on some nights but you most likely will find dew only occurs on those nights early in the morning. I have not really lost any imaging time because of dew or at least minimal amounts.

I think the main thing is turning on the fans early enough to allow the mirror to get quite close in temp to the ambient. If its more than 1C then it will be hard to focus and won't be at its sharpest. .3 to .6 is OK. .1 is sweet. It takes the CDK about 1.5 hours to get close. I am sure it will be similar for this scope.

Greg.

[marc4darkskies]

Interesting - thanks for the info Greg! Surprised dew hasn't bothered you that much. Dew used to cause all sorts of problems for my Tak before I put a dew heater on. On many occasions the whole observatory was dripping wet and the objective fogged over before 1:00am.

[Logieberra]

Marcus, you've probably seen this video already? It looks like your OS control goodies are very well supported within TheSkyX :)

http://www.bisque.com/sc/media/p/86975.aspx

[gregbradley]

I suppose I should put the caveat of that's whqt happens where I am. But I think because the mirror is so far inside the tube, it has the fans blowing air across it, the shroud around it, its not that exposed really.

Hopefully its the same for you. It hasn't been enough of a bother for me to get dew heaters installed yet.

Greg.

[marc4darkskies]

Yep, thanks Logan, I saw that. Made me feel warm & fuzzy :D



Yes, I'll have the same. The shroud should minimise the need for heaters but on the worst nights (as you're saying I think) they'll still be necessary. My fans suck air down towards the mirrors too so on wet nights would this increase the risk of dew on the primary requiring the heaters? :question: Also wondering whether it's best to run with or without the shroud. :question:

[gregbradley]

Yes, I'll have the same. The shroud should minimise the need for heaters but on the worst nights (as you're saying I think) they'll still be necessary. My fans suck air down towards the mirrors too so on wet nights would this increase the risk of dew on the primary requiring the heaters? :question: Also wondering whether it's best to run with or without the shroud. :question:[/QUOTE]

I often wonder about dew heaters. We go to so much trouble to get the mirror cooled and per Paul Hease and Bird you actually want the mirror cooler than ambient rather than warmer. I have thought it would be worth an experiment to get one of those AC units with the hose output and angle one on a stand to blow cold air on my mirror as an experiment to see what effect it has. AC air is also dry and are great for demisting the car windscreen. So it may also stop dewing? But on those nights where it would prevent an image wrecking problem of dew it would be worthwhile. Certainly in Florida/Qld or high humidity areas it would be a must.

I have not imaged with the shroud off mainly because I was worried about the small amount of light we often have in the observatory from transformer LEDs and in my case my computer screen around a corner.
But yes I think you could get some better cooling and air flow by leaving it off. Would it be worth it? I think other factors would probably influence the image far more but every little bit adds to the final result.

Greg.

[jase]

Looks the goods, Marcus. Time for it to produce the goods.
Well done on the purchase...am awaiting first light.

[marc4darkskies]

Thanks Jase. Nope, not going to rush things. One step at a time. :)

Today I made up the RS-232 cable for the Pyxis 3" rotator (6P/6C RJ12 to DB9), and tested it out. I installed the drivers and connected to it via TheSkyX and all was well. Also attached the imaging train assembly - just for a photo op! :D

http://www.pbase.com/gailmarc/gallery/officina_stellare_rc360

[gregbradley]

Looking good Marcus. Are you putting the AO and STL 11 on there?

The MMOAG guide camera chip needs to be the same distance from the pickoff prism as the imaging camera's sensor. If you are more than about 5mm away from it the star images in the guide cam will be so out of focus they become invisible. I found this frustrating when I first tried to use my MMOAG.

Just looking at yours I would say your guide cam will be sitting in air above that helical focuser. I don't use the helical focuser as its too short plus how do you focus it when its got a guide camera sitting in it?? Spin it and tangle the cables? The designer must have been a bit soft in the head.

I substituted a Televue Barlow body and removed the lens bit on it at the bottom to get more height to fit the guide scope. My camera sensor seems a bit closer to the prism than yours. I have MMOAG then about a 12mm wide adapter then the filter wheel (20mm) then the camera and the sensor is 23mm inside the body. So that is 23+20+12+ half the thickness of the MMOAG about 10mm = 62mm.

Anyway something to be aware of when using a MMOAG for the first time.

The other thing is to make sure the adapters areall seated without any minor push out. In my first use the MMOAG prism was sticking back a bit causing the adapter to not seat 100%. I wondered why one side of the images were very soft. The prism has 2 allen key screws on top and you can slide it forward or back to suit and then retighten if its an issue.

Greg.

[strongmanmike]

Not bench testing but coffee table testing :P

Have to say that looks like a real pro instrument mate and once mounted will be the envy of us all :prey2: :lol: While perhaps a tad daunting at the moment, you must be just sooo excited and I think your cautious careful approach is a good idea :thumbsup:

Mike
did you pickup that ping pong ball?

[marc4darkskies]

Thanks for the advice Greg. I think I got the distance calculation reasonably close so we'll see. The adaptor you see is for the STL only, no AO-L. I have the short adaptor as well for the AO-L + STL but that means guiding with the camera - an option I'll have (leaving the MMOAG in place). I won't know the true configuration until I get it out under the stars of course. If I have to mess around with adaptors so be it - no problem - I'm expecting to have to do that anyway. :):thumbsup:

[marc4darkskies]

Cheers mate! Yes, a bit daunting but with some familiarisation I'm starting to relax :thumbsup::zzz2:I'll get nervous again when I put some starlight through it. Will it all work as advertised??! Will my stars be tight? :shrug: :question: :confused2::help::prey: :scared2:

Yes, the ping pong ball has been returned to its rightful owner - Sweetie and her brother Buddy. Below is Buddy after the box passed inspection.

[strongmanmike]

Perhaps you and Greg should consider locating your gear at his property in Biga at some stage in the future and operate them remotely like Paul is doing :)

Says he who still sits at his lappie for extended periods and rotates his dome manually :question: :lol:

Mike

[Howie Glatter]

"That's a pretty cool laser tool you have there. Who makes that?"

Yes, that's my 532nm laser collimator with a concentric circle reticle projection attachment.

"Does it only work on RC designs?"

No, it will work on any Cassegrain down to f/5.6
That scope is beautifully collimated. Enjoy it!

[Satchmo]

With a 48% obstruction at the end of the baffle a perfect system will only deliver a peak intensity of around 50% ( Encircled Energy Ratio ) so visually at medium to high power the views will be underwhelming in terms of star tightness and contrast with 50% of the light spilling into surrounding rings. However its an imaging scope so matched to the right pixel size the low EER due to obstruction , will not have any consequence , aside from the 25% loss of light from the obstruction .

[Paul Haese]

That is the sort of dew issues I face almost nightly at Clayton. Good seeing, dark skies but bad bad dew issues. I have a heater on the secondary of the RC even in a tubed setup. It dews up. The TSA needs to have a dew heater on every night despite having a heater dew shield. Dewy sites need good dew amelioration.

[Paul Haese]

Thanks for the info Howie. That is a pain about not working on RC's. Oh well keep the Tak scope going.

[marc4darkskies]

Thanks for the confirmation Howie!



Yes, aware of the theory, thanks Mark. :) My usage of the term "tight" was relative.



Paul, I think you misread Howie's info mate. Of course it works on an RC (a type of Cassegrain). The RC360 is an RC. :thumbsup:

[pvelez]

Out of interest - does the Howie work on a CDK?

The colimation on the OS looks a cracker.

Marcus, I'm keen to hear your thoughts on the Pyxis.

Pete

[Joshua Bunn]

I think so Pete, for memory Stevous67 used it on his CDK, correct me if im wrong Steve :P

Josh

[Paul Haese]

Yes reading it one way is reads can it be used on RCs? Then the next line is No, reading it another way I can see can also mean it will not only work on RC but also any cassegrains. Thanks for pointing that out.:)

[gregbradley]

There's a special AOL MOAG. If you wanted to use the AOL then you may need that AOL MOAG. You would know better than me how much the AO tightens things up from use with your TOA. Is it worth setting up the extra stuff and cost?

Greg.

[marc4darkskies]

The MOAG + AO-L would not fit in the 236mm back focus. Although I could give myself more, it would not be optimal. Besides, I see an AO-X in my future! :D

[marc4darkskies]

Collimating an RC with the Howie Glatter and concentric ring attachment seems to be quite straighforward. Even though I haven't actually HAD to collimate this beast (it's already looking very good), the steps to take are worth noting.

1) Align the secondary's central spot with the central laser dot by shifting the secondary assembly up/down & left/right. This will align the center of the secondary with the mechanical axis of the imaging train. Hopefully the spot drawn on the secondary really is at the center of the secondary! (See image #1 below)
2) Look at the projected rings on the primary mirror from different angles (careful - that laser is bright!). Now adjust the secondary's tip/tilt so that the rings are perfectly concentric with the primary mirror (see image 2 and 3 below)
3) Adjust the primary mirror's tip/tilt to make the rings projected on a wall perfectly concentric with the secondary shadow (see image #4 below). You can use a ruler to measure if you want to be precise.

It's that simple!! :P:)

It will be interesting to see what the star test shows!!!

See http://www.pbase.com/gailmarc/officina_stellare_rc360 for images with captions

[Bassnut]

This all causing havoc in my brain, I hate you Marcus.

[marc4darkskies]

Aaaaw ... shucks Fred, I hate you too! :love::love2:

PS: :lol:

[batema]

Honesty it just looks fantastic. I can only imagine how much fun and impressed you must be with your new scope. Keep posting images as I love following your adventure and of course cannot wait to see your images.

Mark

[marc4darkskies]

Cheers Mark! Yep, the scope sure has wow factor in terms of looks - in some respects the pictures don't do it justice! OS' attention to detail is without question - that's for sure! There's still plenty of stuff to do before I plonk it on the mount but I'm confident I'll be able to catch some starlight before Christmas (I can only work on it on weekends :sadeyes:).

[renormalised]

It's Italian....that means it's classy and sexy all at the same time :) Like an Italian supermodel :) :P

[multiweb]

Massive scope. Ready with interest. Can't wait for first light. :thumbsup:
PS: In the pattern from the howie glatter on the wall I understand the central rings are reflections from the secondary back onto the primary: what's the outside much larger ring? Direct illumination from the laser's last ring on the wall?

[marc4darkskies]

Yep, I bought a telescope that matches my own attributes ... classy & sexy! :lol::P



Thanks Marc! See the explanation underneath the image on Pbase. :) http://www.pbase.com/gailmarc/image/153390656/large

PS: Atlas has checked out OK. The Rotator and Atlas integrated to TheSkyX no problem. Just need to re-do the through the mount wiring and I'll be ready to install on the mount. Waiting for a RigRunner to do that.

PPS: Also ordered an Aurora flat panel (http://www.gerdneumann.net/english/astrofotografie-parts-astrophotography/aurora-flatfield-panels/uebersicht-aurora-flatfield-panels-overview.html) (420mm)

[marc4darkskies]

Just a quick update.

I need more power at the OTA plus there are now 2 serial devices and 2 USB devices up there. So I'm redoing practically all the cabling. The TOA is now safely in a box and the PME is naked with wires poking out.

See attached (before schematic on the left, after on the right).

[strongmanmike]

...mate hmmm? :eyepop: :nerd: anyway glad it's you and not me, I recon I would just plug er in and hope for the best :lol:...ok well maybe not but if I ever go down this route I may need to have you down for a weekend (or week) of food and drink :question: :lol:

The Aurora Flatfield panel is excellent :thumbsup: (I named it that too by the way :D)

Mike

[marc4darkskies]

:lol: ... funny man. Yes, I AM a geek :nerd: :atom: :astron: :einstein: :computer:



Say, when ARE you getting a PME (??) I tell you what - by the time you get round to doing these kinds of geeky things (yes, you are a geek too - admit it :P) we might be neighbours!!!

[marc4darkskies]

Rewiring finished! Planning to install in the Obs this weekend. I didn't shorten the pier, but by my reckoning it will fit ... snugly!!

[h0ughy]

yes that is snug but not wasting space :D

[ericwbenson]

Hi Mark,
Beware the worst interference is not when the scope is pointed at the pole. The outside edge of the front aperture when looking ~2 hrs away from the meridian (east or west depending on the flip state) is the highest point the scope will get, but possibly worst is when looking near the zenith, the scope is not as high but far from the center of the dome. Watch out for protrusions (motors, ribs, shutter rack, etc) on the inside dome surface, they will always find a collision point!

Before going ahead with the scopedomes in Ark, I had made a 3D cad model and swung the 20" around virtually, I found that I had to optimize the pier height to have about 2" clearance (too high I hit the dome, too low I hit the base ring). Then later when I changed the mount from the PME to the 200HR, again I had to model it. It was a good thing I did since it would not have fit without offsetting the mount on the pier with an adapter plate. Now I have about a pinky's clearance with the shutter motor.

If you get it wrong your best solution (instead of cutting the pier) is to add counterweights to the front of the scope and pull the scope back in the saddle plate. This is fine if your are a long way from the mount capacity...I definitely wasn't with the 20" on the PME!

Best,
EB

[marc4darkskies]

Thanks for the advice Eric. Mine is only a fairly rough diagram but I think I'll be fine. In any case I won't be swinging the scope around much until I've very gently discovered the clearances :). I was planning to go with Option 2 if I had to shift it back a few cm. All will be revealed on Sunday!!

[marc4darkskies]

It was a team effort but we managed to get the scope on the mount without dropping it!! Still a few things to do before first light though - hopefully that will be before Christmas!

Couple more images and commentary at http://www.pbase.com/gailmarc/gallery/officina_stellare_rc360

[h0ughy]

well if no one is drooling now they never will - scope envy is a cruel thing:thumbsup:;):P

[multiweb]

Are you pulling a Sidonio? :lol:

[marc4darkskies]

Nah ... don't be envious! It's all relative anyway, I could never hope to put 5 telescopes on the one mount simultaneously!:eyepop:



Absolutely NO idea what you're talking about Marc! :shrug::P:lol:

[batema]

Looks FANTASTIC. Can't wait to see what this can do.

Mark

[strongmanmike]

Marcus! you and I have more in common than I thought :eyepop: we are brothers :D

Scope looks good :thumbsup:

[h0ughy]

:P now that rubs it in - i am overcompensating for a lack of everything nice. tell me will the 150TOA be the finderscope?

[marc4darkskies]

Thanks Mark. It's been slow going because work makes me pretty time poor :sadeyes: But, there's light at the end of the tunnel - literally! :)


Yo Bro! ... Wassuuuuuuuup? :cool:



Unfortunately, at this point, I don't see the TOA being able to tandem with the OS - there's just not enough space in the dome. Side or top mounting on the OS is not practical either because the TOA is over 14kg without the tube counterweight and 19kg with - too heavy to put on the OS.

[marc4darkskies]

Yes, we're nearly there. This is the first day of two weeks off work so I should be able to move faster now:

Wiring completed today - lots of cabling!!! :eyepop::
http://www.pbase.com/gailmarc/image/153853936/large

Declination counterweight - much easier than sliding the OTA up and down!!:
http://www.pbase.com/gailmarc/image/153853979/large

Too darn hot to work outside anymore today - time for a beer :drink:. Next step is a system test with everything on and connected to the Obs lappy.

Cheers, Marcus

[gregbradley]

Where did you get those declination counter weights from? They look handy.

Greg.

[marc4darkskies]

Yes, they're definitely the way to go - I liked the fact that they're stainless. Needed to buy some stainless bolts (SHCS) to screw them to the DVAs though.

I got them from Bintel: http://www.bintel.com.au/Accessories/Counterweights/Farpoint-Counterweight--br--16---LightBridge/1096/productview.aspx

[gregbradley]

Thanks Marcus.

Greg.

[marc4darkskies]

Well, after a few days of 37C+ temperatures (and a couple of degrees warmer inside the Obs) it was much cooler today so I managed to do the system testing I needed to do. Everything worked fine from within the TheSkyX.

Happy snaps:

http://www.pbase.com/gailmarc/image/153897728/large
http://www.pbase.com/gailmarc/image/153897731/large

The next stop will be FIRST LIGHT! As luck would have it, and you'll find this very strange as I did, cloud and showers are now forecast until the 30th! :lol: :) :( :sadeyes: :sad:

:rain:, Marcus

[RickS]

I hope the farmers are grateful :)

[Paul Haese]

That's a sweet looking rig Marcus. I need to do some cable management too, which you images have reminded me to undertake.

[marc4darkskies]

Thanks Paul. It's hard to make it look any prettier - there are just too many cables!

[marc4darkskies]

Finally the clouds parted long enough to let in some photons!!

Sorry, no pretty pictures - just test images. See the text underneath each image for explanation. Each small panel is 5.5 x 4.3 arc minutes

In short - very pleased! :D

Collimation Check:
http://upload.pbase.com/gailmarc/image/153941599/large

Star Test:
http://upload.pbase.com/gailmarc/image/153941605/large

Cheers, Marcus

[RickS]

Looks great, Marcus. Very flat!

[allan gould]

Nice test images, Markus. Looking forward to first light.
Allan

[marc4darkskies]

Cheers Rick. I'm a bit of a reflector novice but, to my eye, those stars look pretty good too! For completeness though, I really should do an outside focus collimation series (what you see here is inside focus)



Thanks Allan. Buuut ... that was first light! :D Next step is to do a TPoint model so I can start imaging ... for real!

It's worth mentioning this again ... this is out-of-the-box collimation!!! Maybe I'm just lucky, but that's very impressive!

[strongmanmike]

Yep, I recon you can just start imaging there ;)

Just think, you now effectively have what was a cutting edge professional scope (http://www.mso.anu.edu.au/gallery3/index.php/first100years/album09) at Siding Spring...only yours is better :D

Mike

[marc4darkskies]

Hehe ... Yep, that one doesn't have any red on it so clearly it's not a high quality scope! :lol:

[marc4darkskies]

Okay, after reviewing the result, doing some reading and getting feedback from Gino in Italy on the above, some minor tweaking of collimation is required to achieve optimal performance. Now, could the person who caused the clouds and showers to roll in please step forward! ;):D

In other news, while the native, uncorrected optics are F8, I found out that the flattener used causes an increase in focal length to F8.7! I discovered that while doing my first plate solves & TPoint run (0.59 instead of 0.64 arcseconds/pixel image scale) and this has now been confirmed by Gino. This is more good than bad news for me since I'm after narrow field views!!! :D

[Paul Haese]

Yes those plate solves would have not worked with a change in focal length, though as you say it is a good thing to get a slightly narrower field of view. Looking toward the images Marcus. I am keen to find out what these scope are like as I see this as a likely contender to the replacement of my RC12" at some point in the future.

[marc4darkskies]

It did actually work even when I told it the image scale was 0.64 - I guess the difference wasn't large enough to confuse the software.

[marc4darkskies]

Here is an interesting picture. The mirror is attached to the cell (the red anodised plate) centrally. The cell also has 5 radial supports each comprising a pillar and a grub screw (highlighted) that holds a metal plastic-backed disc in contact with the side of the mirror to prevent any small radial movements of the mirror. During transport, one of the discs had come loose and fallen out - almost certainly because the grub screw wasn't tight enough. To fix this I lifted the carbon fiber tube up to reveal the cell and gain access to these pillars to replace the disk.

You'll also notice the heavy duty spring that loads the collimation screws for the main mirror. No wonder the screws are tight!!

By the way, before I did the fix for the missing radial support, my first TPoint model (126 data points) was 14.6 arcsec RMS. I guess I should probably bolt the scope to the PMEs versaplate - currently it's only attached via the dovetail and friction.

[marc4darkskies]

I fiddled with collimation a bit last night and got it as good as I can.

It was a hot & sweaty night but the sky stabilised nicely so I took 3x5min test subs (1x1 binning) of the vicinity of NGC 3263 last night to check star shapes. There's now only very minor egg shape in the corners, mostly at the top of the frame. I'm going to call it good though!!

Each box is full res and only 2.3 x 1.7 arc minutes (ie a very small patch of sky) at 0.59 arc second/pixel. The boxes represent the extremities and middle of the frame. The 3 subs I took were dark subtracted and sum combined. They were stretched of course but no flats, decon or sharpening of any kind. Some of you might notice why I'm pretty chuffed with this raw result! :D

[marc4darkskies]

This commissioning thing never ends!! :help: Here's how I mounted my flat panel yesterday (Gerd Neuman's Aurora Flat Panel) after a lot of head scratching.

A Vogel articulated tip/tilt wall mount monitor arm (a small one) - bought at JB HiFi plus a bit of DIY thrown in to attach it to the dome. It allows the panel to be positioned orthogonally and close to the front of the OTA. I can remove the panel and support easily. Just needs a lick of black paint now.

[strongmanmike]

Oooh aren't you a clever little Vegemite :)

I just don't use flats :P - that's pretty easy :lol:

Mike

[lazjen]

That's a very good idea and helps keep things neat and easy to use. :thumbsup:

[RickS]

Nice idea, Marcus! Now, if only I had an obsy to hang mine on...



Try that at f/9 Mr Smartypants :lol:

[Bassnut]

Ha, of course you are,excellent beneficial snafu :D.

Following with keen interest Marcus, progressing wonderfully :thumbsup:

[Bassnut]

Flats at f9 ?, Nah, the longer (better) the F gets the less you need that crap. With NB at f9........ Never :thumbsup:

[peter_4059]

Marcus - just wondering what the orange coloured things are between the mirror and the red plate (above the colimation bolt) in the second image?

Peter

[gregbradley]

Looking very good Marcus. It looks like tight star sizes in the corners which is great. Is there much vignetting?

Greg.

[marc4darkskies]

Yes, it took me a while to figure it out though! :rolleyes: The thing tilts up and down 10 degrees and with the mounting accommodating the dome curvature (roughly) I'll be able to pretty well push the flat panel against the front the the OTA.



Thanks Rick. So what's your problem then? Obsies are easy to build! :shrug:;)



What do we want? FOCAL LENGTH!! When do we want it? NOW!!!
Alas this wretched cloud is slowing progress to a crawl. Currently twiddling my thumbs as a completely clear day turned cloudy just as I powered everything up!:mad2:



I believe they might be mirror heating elements. I didn't think to investigate. :rolleyes::screwy:



Thanks Greg. I'll let you know once I take some serious images



Mmmmm .... Vegemite!!

[peter_4059]

They look a lot like Kendrick mirror heating elements only they are not attached to the mirror?

http://www.kendrickastro.com/astro/newtonian.html

[gregbradley]

Yes I see what you mean, NGC3263 is a tiny and dim galaxy and its showing up quite well there. Very promising.

Greg.

[marc4darkskies]

I believe you're right Peter. There is foam underneath most of it to press it against the mirror (see another picture I took below). Perhaps I need to add some more!



Yep, that's it! Remembering this is a raw image without the full compliment of longer subs and processing techniques (including decon), I'm very pleased!

[peter_4059]

Marcus,

I see Kendrick have these heaters for RC primary mirrors:
http://www.kendrickastro.com/astro/RCoptics.html

I had one on my 10" Newt but found the Kendrick controller was switching it to control the temperature (I assume it was full on/off with the duty being controlled by the amount of time it was on). This was causing the focus to shift so I've stopped using it. I wonder if your scope control system has a smarter way of controlling the heater duty (perhaps varying the voltage?) so it doesn't cause problems?

Peter

[marc4darkskies]

It's still early days - I haven't done any full-on imaging yet. Besides, in this hot weather (with short warm nights) the mirrors have usually ended the night a couple of degrees above ambient and the dew point. The controller will only activate the heaters to keep the mirrors at a set point above the dew point - and I haven't gotten close to the dew point yet to see what happens.

Also remember that my mirror substrate is Sitall with an incredibly small coefficient of expansion so, as temp changes, nothing much will happen. I haven't seen temperature based changes in focus yet.

[peter_4059]

I hadn't considered the mirror material - good point!

[gregbradley]

Sitall. That was a smart upgrade choice. I notice with my CDK temp needs to be within .5 to 1C of ambient to get best focus and sharpest images. Not that its a big deal as it just takes about an hour to get there perhaps an hour and a half.

But I think that is a useful upgrade.

Greg.

[strongmanmike]

Man! this beauty must have hit the bank account :eyepop:...all awesome though and.... ya only live once :thumbsup:

[UniPol]

I'm still trying to figure out ways to come up with the necessary $45-50K for one of these superlative ultra supreme scopes. It is either buy lots of scratchies or get into real estate.

[strongmanmike]

I'm thinking just extend the mortgage...:question: why not? just be in debt a little (lot?) longer :thumbsup:...hmmm? thinking, thinking...then there is the PME and automation gear for the (new) dome...Hmmmm? thinking thinking :question:...thanks Marcus :rolleyes: :lol:

Mike

[marc4darkskies]

Yes indeed - temperature is not something I worry about. I was 2 or 3 degrees above ambient for most of the night and my focus seemed fine. Night before last sucked though - terrible seeing. Last night I couldn't tell - it was cloudy!!!!!!



Yep, I dropped a few bob on it. Still a lot cheaper than the equivalent RCOS would have been though!



You must want a BIG one then Steve - mine's only a little 14" ;) ... and it wasn't THAT expensive!! :eyepop:



You only live once Mike! And you can't take it with you!!! You know, a PME II would look nice in your dome!! Then you'd also have an excuse to buy a 100kg telescope to put on it ;)

[TrevorW]

Close to $40k including mount based on OPT prices so a hefty investment hope you've insured it :)

[marc4darkskies]

Well I guess my charmed existence had to end sometime. So far nothing of any significance has gone wrong. Everything has checked out and I'm thrilled with the quality of the optics and the promise they hold. But, as someone said to me recently, there will always be something that isn't perfect! Even, dare I say, with a Ferrari! :lol:

I've discovered I have a stray light issue ... oops! Off axis starlight is impinging directly on the outer edge of the flattener lens causing flaring. In typical fashion, OS has quickly stepped up and, after carefully modelling my particular system, is now engineering a baffling solution that better matches my setup. Apparently, my flattener is non-standard but engineered to more optimally match my imaging train and the backfocus it needs. It sits further forward in the scope than normal, just enough to have off axis light hit it directly.

I'm not really fazed by this kind of thing. Of course I was a little disappointed initially, but after seeing how well OS responded and the tentative solution they are proposing, I'm more than confident of a happy ending.

In the meantime I have to figure out what's causing BSODs to suddenly start happening in my Obs lappy! :mad2:

[RickS]

Glad to hear that OS are stepping up with a fix, Marcus! Don't expect that much help from Microsoft on the BSODs :lol:

[allan gould]

Thats a great response from the manufacturer. Im sure it will be fixed to your sattisfaction.
Allan

[strongmanmike]

Now who could that have been :shrug: :whistle:...clearly your guys are on to your issue quick smart, good to hear :thumbsup:

Mike

[marc4darkskies]

Video error - not sure whether to blame MS or Toshiba. Even though there are later drivers for an NVidia 560M, I can't update them in a Qosmio X770!!! :mad2:



Yes indeed, I've been very impressed with their after sales service (and Cris' as well)! I just need to be patient - which is quite hard when I'm chomping at the bit to see what this baby will do!



You jinxed me Mr Sidonio .... I hope you're satisfied!! ;)

[Peter Ward]

Sorry, that's just not possible.

Even when they aren't running they are still perfect :D

http://www.youtube.com/watch?v=WAlHlaWjWyo

As penance, you need to spray paint Stella green this instant...and don't worry about masking off the optics. :)

[gregbradley]

Off aixs flares were an issue for the CDK17 as well. It required several solutions in my case. A redesigned secondary shroud that covered the last 3-4m of mirror, baffles that went in the primary tube and also the corrector. And the last one was around the primary mirror itself where it meets the tube.

Greg.

[David Fitz-Henr]

Hey Marcus! I've just caught up with all this and it is all looking very impressive! :thumbsup: Although it is an annoying issue the problem with reflections of the edge of the flattener should be relatively easy to fix.
I'm looking forward to seeing some high-res shots from you real soon :)

[marc4darkskies]

Thanks guys. Yes, stray light usually just requires some additional baffling and that's what OS are intending to provide me. In the meantime I bought some flocking board (heavy & light) and self adhesive tape.


Using the heavy board I fashioned a crude secondary shroud enlargement in the form of a truncated cone (think of one of those protective dog collars). I enlarged the obstruction from 44% to just over 48%.
Using the tape I flocked all the trusses
I flocked the full length primary baffle using the light board
I extended the primary baffle by 10mm
I made 2 ring baffles out of heavy black art paper and placed one at the back end of the primary baffle and one just in front of the flattener. It's a bit of guess work without ray trace and schematic diagrams so I just eyeballed it
I flocked strategically inside the imaging train in two places - there were a couple of obvious shiny spots.

Flats show some vignetting but it's not bad - 18% at the extreme corners of the STL (see CCDInspector result below). No doubt the official OS fix will be better that this!

I just need the weather to go away now to test, but I'm crossing my fingers that I've done enough to start imaging!!

[gregbradley]

I flocked my trusses as well but I did not notice any difference from this. What I did notice made a difference was the angled secondary shroud Planewave made and the primary mirror baffle. Baffles around the corrector made a small difference but not that noticeable to me (perhaps more than I realise as once something does not flare when it would have before you really need the same field before and after to see the difference).

I see Astronomics promote the fact they blacken the edges of their secondary mirror and the corrector lenses. Something to consider. I haven't done that myself but wonder if its worth it.


Greg.

[marc4darkskies]

Hard to say what has the biggest effect but flocking the trusses will help. I also had fairly shiny plastic netting around one truss hiding a ribbon cable to the secondary that was probably a significant contributor. In any case, there is almost no part on the inside of a scope that doesn't contribute to stray light so the best thing you can do is to get totally flocked! :D

My flocking and baffling effort worked a treat! Beautifully contrasty flat field (after applying the flat of course).

I did have other issues crop up though - unrelated to the scope. Guiding artifacts suggesting my PME probably needs a spring plunger adjustment to accomodate the heavier load (around 45kg). My Obs lappy is suffering BSODs that I think are caused by overheating (Toshiba Qosmios have a reputation for doing that). If the theory is correct I think I have a work around for it.

The good news is that OS have designed quite a clever fix for my problem so I can do away with my secondary dog collar and primary baffle extension. ETA uncertain but not far away I think! Their fix means my secondary obstruction will return to 44% (before I added the dog collar)

[strongmanmike]

Hmm seems to be a lot of flocking and other kinky stuff going on at your place Marcus ;) :evil2:

Meet the Flockers :P

[issdaol]

well flock me !! the whole thing is quite baffling really :rofl:

[gregbradley]

Marcus does the secondary mirror have blackened edges? Also the corrector?

I saw an ad for Astronomic telescope and they were promoting blackened edges of the secondary and the corrector lenses.

The Planewave isn't.

Greg.

[marc4darkskies]

I don't know. I haven't asked nor has that been advertised. In any case, the result after flocking & baffling tells me nothing more is needed. I'll let you know after I've imaged the Horsehead with Alnitak out of frame! :)

[marc4darkskies]

This gives you an idea where I'm at right now. THIS IS ONLY A TEST IMAGE of the the field I'm using for the commissioning process, replete with guiding errors and less than perfect collimation. It's a mere 40 mins of exposure (8 x 5 minute subs) - far less than it would need for a "real" imaging run!!

During this test I discovered I have a guiding problem by virtue of the fact that the payload on the Paramount ME is now larger than before (45kg or nearly 100lb). I believe the spring plunger adjustment on the RA and DEC axes needs some tensioning. The mount's accelaration also needs to be reduced. The stars in this image are actually elongated towards the bottom of the frame in the raw subs and just visible here. The elongation has been disguised by the stacking and stretching I've done - but it's there!! Collimation is also not as good as it can be.

Full res: http://www.pbase.com/gailmarc/image/154310541/original

FOV is 38 x 25 arc minutes @ 0.59 arcsec/pixel imaged between 31 and 41 degrees altitude with average seeing. Some cropping to eliminate stacking artifacts. Processing was rough-as-guts minimal with stretching and some noise reduction only. No deconvolution was done.

I'm salivating at the thought of getting a proper imaging run under my belt after I get the issues sorted!!! :D

[gregbradley]

Looking good Marcus. Elongated stars at the bottom of an image but not at the top would indicate a tilt problem rather than a tracking problem which would be global.

You may need to shim your adapter to pack it up on one side. A bit of trial and error.

Which night was that? We had good seeing 2 nights and bad seeing on another. Thurs night was the bad seeing night and Wed and Fri were good.

Greg.

[marc4darkskies]

In the raw files the elongation is about equal but there may be some tilt as well. There were other obvious symptoms of acceleration and spring plunger issues - elongation in the direction of travel when calibrating. One step at a time though!!:)

I did this on Sunday and Monday nights (above average seeing) - but I only had short tinkering sessions because they were work nights. I was also also dealing with BSODs (maybe resolved) and trying to get the rotator to work in synchrony with CCDAP and TheSkyX (unresolved)

[gregbradley]

Oh Gawd, getting devices to work with Sky X - ouch. I can't get it to connect properly to my SX camera. I am sure they will get there eventually.

I sometimes see elongation when callibrating. Not always though. So that is a symptom is something needing adjustment?

Greg.

[marc4darkskies]

It's not TheSkyX - it's more CCDAP->TheSkyX. I think I'm just doing domething dumb. I've NEVER had trouble getting anything to work with TheSkyX.

Well, if the payload on your PME is large, the inertia of the scope may cause the worm to ride up on the gears when it stops & starts - a kind of slop I guess. The spring plunger adjustment instructions say when the payload gets to 100lb then the spring plunger screws should be 2 turns out (pushing the worm against the gear harder), not 2.5, and slew speed should be reduced to 75%.

[strongmanmike]

Looking good Marcus :thumbsup::thumbsup: viewed at 70% in my browser you wouldn't know there was a problem :thumbsup: so when it is sorted you look to be on a winner :cool:...regarding the PME issues (I hear about a lot of these :question:) get yourself an old Tak NJP mount (http://www.pbase.com/strongmanmike2002/image/141334067/original) :lol:...loaded up to the hilt and no PEC or ProTrack... it just keeps on keeping on (http://www.pbase.com/strongmanmike2002/image/141334127/original)... :)...in the 9 years I have had it not one mount adjustment has been made (touch wood)...can't do a meridian flip or remote stuff though :doh:...still, wouldn't mind me a PME :question:

[multiweb]

No pressure. All forgiven then... :P
Seriously I can't see anything wrong with that field. When's first light you tease.

[Paul Haese]

Got the same drama myself. The rotator will not connect in SkyX when commanded by CCDAP. It will work though if you connect rotator in CCDAP alone. Something to consider.

[marc4darkskies]

Now why didn't I think of that!! :doh:You should see underneath our rugs at home - there's so much dirt under there I keep tripping on them! :P:lol:



My PME is a gem (pun intended). So it's not so much an issue or problem but an adjustment. They do say to adjust spring plungers depending on the payload.



Try putting 46kg on it? :P



The annoying thing is ... I attempted to fine tune collimation yesterday and completely ballsed it up! :mad2::sadeyes: I've still got my collimation L-plates on!!! Tell you what ... this large aperture commissioning stuff is not for the faint of heart!
EDIT: My stray light issue set me back a couple of weeks, otherwise I'd have been imaging by now. :sadeyes:



Everything connects fine and works in TheSkyX and CCDAP, but CCDAP doesn't move it to the right angle when I start a session. Some kind of offset I think. I'm just controlling it from TheSkyX "manually" at the moment. I can also link it to the FOV indicator in TSX and it works fine. I'll figure it out when I fix my collimation blunder.

[strongmanmike]

Actually... I was pretty close to that in that picture, check out the counter weight end ;)...less with the SX gear now though :thumbsup:

[SkyViking]

:eyepop: I wonder what they put in those scopes to make them so heavy? Is the construction lightweight, or does it just not matter on the big mount?
Btw, is that with or without counterweights...? If you have another 45kgs of metal sitting at the other end of the shaft then the inertia must be quite a bit when making fast guiding corrections. What guiding frequency to you plan to use?

Just for comparison, although mine is a bit smaller at 12.5" it's weighing in at 16kgs which rides very smoothly on the Losmandy G-11 :) I figure a 14" version would push it to maybe 18kgs. :lol:

Hope to see your first deep image soon Marcus :thumbsup:

[marc4darkskies]

Thanks Rolf! Yes, you're spot on. Guiding frequency has a lot to do with it. The stiffness of the spring plungers is only part of the solution. My default minimum period was 2 seconds in CCDAP (way too quick), but have now increased that to 5 sec and reduced aggressiveness. I will probably increase the guide period further when I start imaging and/or guide stars are scarce - the PME doesn't need guiding that fast anyway. I have also yet to add the AO-L into the equation which will eliminate at least 95% of mount based guiding corrections (depends on polar alignment).

The bare weight of the OTA is 34kg and I have another 11 or 12 (as near as I can figure) in imaging train plus other accoutrements. So yes, the total payload is 90kg - a lot of inertia!

[White Rabbit]

OMG, this thread has been the biggest tease of the century. Hurry up and get yir kit off and show us some images already....:D;)

[SkyViking]

That's interesting Marcus. Although there are different schools of thought I'm personally in favour of fast guiding corrections. Except of course if you use AO so it doesn't matter, which you plan to do anyway :)
In my case (no AO) I typically guide at ~2 Hz (0.5s), and then only increase the guide exposure if the graph is not behaving well (this depends on seeing and wind), but always keep it between 0.5s and 1.5s.
Or put another way, if the guide star has moved then I don't want to wait, say, 5 seconds for an exposure before corrections are sent to the mount.

[strongmanmike]

Same here, usually stick with 2 sec as a rule, only when the seeing (or in the dreaded past THE WIND) is bad have I upped it to 3 or 4 sec :)

Mike

[SimmoW]

Ha, corr, Astroporn!

[ericwbenson]

Actually the integration time for the guider does not affect how fast the correction is applied. The "guide speed" of the mount is what determines the motor velocity, the angular distance is controlled by the length of the correction. So many small corrections can be better than fewer large ones.

When I had the PME under the 20" the guiding was ok, if not exceptional, if the wind was still. But too much breeze (even with a dome) would push the scope and stretch/sqeeze the mount components resulting in bad guiding. And worse often I think it would oscillate in RA, which is more cantilevered than DEC (7 x 20lbs counterweights on the extended shaft will do that !!!) So the PME is a great mount, but not impervious to aperture fever.

Best,
EB

[marc4darkskies]

You're quite right to remind me of the guide speed - something I hadn't adjusted yet - thanks. Yes, I know the guide period has no effect on on guide speed - the theory was that if the mount is oscillating in RA then it will spend less time oscillating with a lower guide frequency. As it happens I've reduced, but not eliminated the elongation, so guide rate might be the clincher. Once I've got everything right I'll do a large model and activate protrack as well.

[Joshua Bunn]

By ''guide rate'' do you mean the aggressiveness of the guide corrections?

[gregbradley]

Never considered changing the guide speed. That could be worth checking out.
For what its worth I find best results vary when it comes to guide exposures.
In poor seeing I get better results with fast corrections like 2 seconds. On a stable night 5 or 6 works well.

I got better guiding with a 300point t-point model and Protrack activated as well as PEC and autoguiding. Which is what I use now.

I think a Pempro PEC curve might even tweak it a tad more compared to Precision PEC or Sky X.

If you are getting oscillating guide errors my suggestion is to make your balance slightly off to the east to load the gears a tad so the backlash doesn't cause a bing bang effect. That worked on my PMX when I encounter that which I have the last 2 times I used it.

Greg.

[marc4darkskies]

No. The guide rate is the speed of the correction that is applied to the telescope's position expressed as a fraction of the sidereal rate. The default rate for SB mounts 0.5. I.e. on the RA axis this means that the tracking rate will change to either 0.5 or 1.5 times the sidereal rate depending on whether the tracking error is west or east. On the Dec axis corrections will be +-0.5 times the sidereal rate. Aggressiveness is the proportion of the computed correction that is applied. I.e. a 1 second computed correction will be only a 0.6 second actual correction if aggressiveness is set at 6 (10 = full correction applied) ..... I think! :).



Tried that with no effect. There is no backlash per se. My theory is that this is more a vibration set up when starting and then stopping (via a guide correction) a large mass. The measures I've taken support this theory - adjusting the spring plungers (small effect), reducing aggressiveness and increasing guide period. I suspect now, if I'm right, that correct guide rate + aggressiveness settings will solve the problem. However, I won't do any more testing until I've got my collimation sorted out.

[gregbradley]

Tried that with no effect. There is no backlash per se. My theory is that this is more a vibration set up when starting and then stopping (via a guide correction) a large mass. The measures I've taken support this theory - adjusting the spring plungers (small effect), reducing aggressiveness and increasing guide period. I suspect now, if I'm right, that correct guide rate + aggressiveness settings will solve the problem. However, I won't do any more testing until I've got my collimation sorted out.[/QUOTE]

Was adjusting the spring plungers hard or easy? I should look at that. Is it in the manual or is there a paper about it?
Yeah that was only on my PMX not PME. I am running similar or more mass and I use aggressiveness at 6 and with good seeing and no reducer but with MMOAG 6 second guide exposures with PEC. Min move .1 max move 2. I get round stars routinely. With guide scope and reducer I have to be a little careful of flexure but as long as guide scope is locked down hard I get round stars 10minutes, occassionally a small amount of elongation in 10 minute subs. Enough for me to consider an OAG/FW thin combo from Starlight Express at some point.

With Protrack I got an additional slight gain.

Greg.

[Joshua Bunn]

Thankyou Marcus

[rat156]

Hi Marcus,

By your own post earlier, you don't actually start or stop the mount in RA when guiding unless the guiding rate is set above 1, which would be silly to do, the mount slows down or speeds up only, so this should not cause oscillation. Don't forget to do the calculations to work out you minimum guide correction, depends on your image scale, it's something many people have set way to small.

http://www.ccdware.com/resources/autoguidercalcv4.cfm

Cheers
Stuart

[marc4darkskies]

Pardon my imprecise language Stuart! I meant starting and stopping a guide correction or better, speeding up / slowing down tracking!! :lol:



I appreciate this advice. I've never imaged at 3100mm and it's become increasingly clear that I need to pay more attention to tuning my guiding to achieve an optimal result - a learning experience. I confess I hadn't even realized that the minimum move setting is important. It's conceivable that if set it too low the mount will constantly be trying to apply tiny corrections, possibly contributing to artifacts.

[PRejto]

Hi Stuart,

Thanks for pointing out that calculator!

Would you be able to post some "rule of thumbs" for the MX and various seeing conditions? (Peak to peak max allowable error & max movement)

Thanks!

Peter

[gregbradley]

Interesting calculator. I plugged in some figures for my setup and it said .5 min move. I normally set it to .1. That mean more corrections are taking place than may be needed. I'll try that out tonight with .5 to see if I can see a difference on my PME (about to start imaging).

This is with both PME and PMX. I usually set max move to 2 as I find prolonged guide errors greater than 1-1.5 result in unacceptable stars.

With poor seeing I have gotten good results going either way. Shorter exposures with more rapid corrections and also with longer exposures hoping the seeing fluctuations don't last that long. So a bit inconclusive. Perhaps raising the min move in poor seeing would be another tool to battle it rather than only adjusting guide exposure length like I have.

Greg.

[rat156]

I'd love to Peter, but it all depends on the your image scale. I'll note down my settings next time I'm imaging, that's about all I can do. I'm by no means an expert on this. If we all share our guiding settings and the reasons for them we may all be able to gain experience and come to some consensus, probably in a new thread though.

Cheers
Stuart

[gregbradley]

Just by way of feedback. I used that calculator for my CDK and Trius. I set the min move to .5 like it recommended up from .1 that I normally use. It worsened the images quite a bit. My guide errors even with PEC and Protrack on are .05 to .3 for 80% of the corrections and the rarely over .5. So that meant it was not being corrected for 85% of the time if not more.

The bottom line very often with these types of calculators etc is its hard to beat empirical testing - ie. the actual performance as opposed to a theoretical. Trial and error whilst slow tends to get you involved and you know what is best for your system under various conditions.

For my PME with a guide scope at 2 metres its 2 second guide exposures, .1 min 2 max move. aggressiveness 6.
At 3 metres and a MMOAG it is 5 or 6 second guide exposures and same min/max.
Both with PEC and Protrack (300 point model) on.

For PMX I use about 5 second exposures with MMOAG, 6 or 7 aggressiveness, .1/2 min/max at 1260mm focal length and PEC on (no Protrack as I don't have a good enough model yet). If its a bit windy I would reduce guide exposures to 2 secs. No delay on any of these. Direct guide on all of them. Quite an accurate polar alignment on both and of course this is the first step to get perfect and worth the effort.

Greg.

[marc4darkskies]

Just a short recap.

I'm about a month behind :sadeyes: but it's been well spent learning new things. Hopefully by the time the moon has gone I'll be imaging!

Here's a list of the things I've had to think about & address:

Stray light issue: Resolved:


OS primary baffle add-on (pending delivery)
Flocking and a couple of makeshift ring baffles

Guiding issues: Resolved. The guiding artifacts observed were never visible with shorter FLs of the TOA-150 and can easily be hidden by seeing. At 3130mm and at the image scale of the internal guider - a TC-237 built into the STL (0.98 arcsec/pixel (binned 2x2)) - any issues stand out like dogs b*lls:


Spring Plunger stiffness adjustment because of increased payload (45kg)
Auto-guide tuning - increase the minimum move from 0.01 to 0.2 arcsec
Auto-guide tuning - PME guide rate reduced from 0.5 to 0.3 x sidereal
Auto-guide tuning - Aggressiveness. Not so much a change but a greater awareness that this can be variable depending on conditions
PME tracking rate too fast(??!!) Stars constantly drifting west - quite rapidly. I had noticed this before using the Tak but let it be guided out. At the longer FL it's now very obvious. Reducing the rate to 99.85% eliminated all residual drift in RA. I've seen others report this on the SB site but they were dismissed with the catch-all recommendation to invoke Protrack to remove polar alignment issues
Redo PEC training
Still need to redo TPoint model and adjust mount altitude to remove dec drift.
Still need to invoke ProTrack and see if this addresses part or all of the tracking rate issue mentioned above (if I restore it to 100%)
Attach the AO-L and do some proper guiding!

Collimation: Almost resolved


Really a result of my ignorance on how to collimate. Now gradually homing in on the optimal settings after ruining the initial factory settings. Learning how to use the Takahashi Collimation scope has helped a lot.

Tilt of the imaging train - not sure if this is a problem yet - will know when all of the above are put to bed

Hardware & software: Amost resolved.


I had to get the OTA, Atlas, Pyxis Rotator working in TheSkyX and CCDAutopilot. Most of this was pretty easy but have been spinning my wheels on the rotator + CCDAP integration (can't seem to remove an offset).

Lappy BSODs:


A simple overheating issue - probably because of a greater load on the CPU (?). Easily fixed by better ventilation. A very annoying distraction though!!

This was a big migration for me from the ultra simple days of imaging with the TOA (relatively light, perfectly collimated and short focal length). I underestimated the time and effort required, especially having to hold down a demanding job and being slave to the weather :mad2:. As a result I can safely say that this kind of upgrade is not for the faint of heart or the impatient!!

A big thank you to those who have contributed their thoughts & suggestions along the way! :thumbsup:

[gregbradley]

Did you see much improvement increasing min move from.01 (very low anyway) to .2?

I changed mine from .1 to .5 and it made things worse by quite a bit. But that's a more subtle change. It implies minor errors .2 and below are not really errors at all that can be guided out? Or are below the seeing so it could be just as easily as seeing rather than a gear imperfection?

Greg.

[marc4darkskies]

Correct, I've deemed errors of 0.2 arcsec or less to be negligible for mount based corrections. And yes, clearly 0.01 was ridiculous but I'd never had cause to think it was hurting guiding. I can't say for sure that things have improved but, qualitatively, it looked like the guide errors settled down.

[gregbradley]

Thanks Marcus. I'll try that out myself.

Greg.

[multiweb]

[/LIST]How did you manage to do that? With the holographic concentric pattern? So what the correct way of doing it?

[Joshua Bunn]

[/LIST]
Hi Marcus,
was the drift you observed, without Protrack on and without autoguiding? simple flexure of the imaging train will have a similar effect to this I would imagine, which protrack will take care of.

[strongmanmike]

It has been exciting for us to watch on, I for one marvel at your thoroughness Marcus and I have confidence that you may well in fact surpass your stellar efforts with the AP wannabe TOA after all :P ;)

Mike

[marc4darkskies]

How did I do that? Well, think of trying to tune a Ferrari using a sledge hammer. Specifically:


Making secondary tip/tilt adjustments during a star test that were way too big ... more that 1/8 turn
Making multiple adjustments to the secondary without writing down what adjustments I did.
Making large primary tip/tilt adjustments without marking the starting points.
Not using the collimation scope to establish a baseline view of the system. I have no idea what the factory setting looked like through the collimation scope.

I am fixing it now using the collimation scope and only small primary tip tilt adjustments during star tests after marking the starting points with a whiteboard marker on the adjustment screws (large nobs). Any secondary adjustments indicated during a star test need to be TINY, be done one at a time and carefully noted and the result analysed. Since the collimation scope says the alignment of the secondary is already correct, great care is needed.

Unfortunately, the holographic laser is hard to use in the confined space of the obs. It's fine to do radial alignment of the secondary and to get close with secondary tip / tilt, but it needs to project the rings at some distance I think to be able to fine tune - and I’m currently thinking of how to do this.



Without protrack or autoguiding. Flexure would not manifest significantly (several arcseconds) in such a short time frame (60 seconds).



Thanks Mike - very kind words ... after I chose to ignore the TOA-envy comment that is :P:lol:

[marc4darkskies]

Well, two months has gone by and apart from some testing of stray light fixes and some daytime collimation (and learning!), this last few days has given me some clear nights. Seeing has been bad to average until the wee small hours of this morning when, during a couple of (tiny!) collimation tweaks the sky just went still :)

This is a single 5 minute exposure in the vicinity of NGC 6681 taken during a high waning gibbous moon and after some collimation tweaking. The seeing was excellent (for Sydney) and the best I've had so far. The drawback of course is that good seeing shows up even minor collimation issues! :sadeyes:

Though collimation, particularly on the right hand side, is not yet acceptable, the good news is the smallest discernible separations are around 1.5 arcsec. Only calibration (with sub-optimal flats) and stretching was done. There was no decon or sharpening done of any kind.

I'm getting very close now and this is a very heartening result! :D

No point looking at a smaller version so here's the full res vers (remember - this is 0.59 arcsec / pixel!):
http://upload.pbase.com/gailmarc/image/155310844/original

Cheers, Marcus

[SkyViking]

That looks superb :D You've got a great FOV with nice crisp resolution for sure. I can see a bit of coma/distortion along the right edge, but it's certainly very minor.
Can't wait to see what images you can produce with your new toy :thumbsup:

[Joshua Bunn]

Looks like you're nearly there Marcus. Small tweeks from now on hey :) with these fantastic scopes and big chips and high standards we set for them and ourselves, it does take some time, but the rewards certainly come.

[strongmanmike]

Wow, two months worth of mega data that :eyepop: Paul will be very proud of you :P

Mate diplayed at 67% no one would suspect a thing :)

Keep the faith, I see perfection on the horizon :thumbsup:

Mike

[marc4darkskies]

Won't be long now, thanks Rolf. Just need a few more clear nights to master this star collimation thing (in the dark, on a step ladder, in a cramped observatory and not knowing / forgetting which way to turn what adjustment screws! :lol:)



Cheers Josh! I confess I was starting to worry - just a little bit - but now I can see the optics will indeed perform the way I'd hoped. Just need this cursed weather to cut me some slack to get the stars to their rightfully round shape!



:lol: With the Tak I think my average was around 8-10 hours and there is no reason to think that will increase!!! Besides, 10 hours on the OS will be equivalent to about 14 hours on the Tak (operating at F11.7).

67%?!!! Never!!! Wash your mouth out!!

Cheers, Marcus-full-res-Davies

PS: I'll be a happy chappy if I can just nip at the heels of perfection! :)

[marc4darkskies]

Okay, last post to this thread to close it off.

Stars now appear to be round to the edges of the field (in so-so to average seeing)! Soooo, time to start imaging again!! :party: .... if I remember how that is and if the clouds, moon and seeing cooperate!! Seems like the only clear nights I get these days are when the moon is up!! :mad2::sadeyes:

Hmmmm, maybe time to get into NB! :question:

Cheers, Marcus

[RickS]

I'm looking forward to some images from the new scope, Marcus!

[allan gould]

Baited breath here.
Allan

[strongmanmike]

Marcus - the afternoon before the next clear night without work the next day :D

Wanna go for a Telescope? (http://www.youtube.com/watch?v=UC_n_CxSZSk)

[marc4darkskies]

This is only 2 hours of luminance data so it's early days for this image (!). There isn't enough signal yet to be able to mitigate the noise so yep, it's still there! This also stopped me from doing much processing - but I at least made it look presentable I hope. I need at least another 2 to 4 hours of Lum to make a meal of it.

In any case :):):) ... this was the real first light of the new (now collimated) scope!!!!!! :cool::party:
The seeing on the night was only average with raw FWHM of 2.06 arcseconds for the stacked frame. I did some mild deconvolution which bought that down to 1.75 arcseconds. Stars appear round (enough) from edge to edge. ... I'm well pleased! :D

Full Res & full frame (less a bit of edge trimming for stacking artefacts): http://www.pbase.com/gailmarc/image/155783443/original (http://www.pbase.com/gailmarc/image/155783443)

Cheers, Marcus

PS: This is of course NGCs 5101 (left) and 5078 - a mind bogglingly beautiful field! Next post will be in the Deep space section when it's finished! :D

[niharika]

Nicely done Marcus, level of details are already popping my eyes :eyepop:

[MrB]

Wow, so many fuzzies!
I lost count after 30-something.
You're just teasing us, can't wait to see the finished image.

[Paul Haese]

Hi Marcus. Will you try 30 minute subs for me please? Say 3 if you can. I am curious as to what you will get with that duration subs. I have been doing 30 minute subs on the 12" and getting very good ADU results.

The stars look slightly rectangular to me. This might well be guiding related though or maybe a dud sub somewhere. The STL is certainly noisier than the STXL. I had forgotten how much extra noise there is from the 10 degrees less of cooling. Time for a new camera????

This scope has the corrector in the baffle is that right? How much back focus do you get with these scopes?

[marc4darkskies]

Thanks guys!



No. Not until I do Ha. I never do 30 min LRGB subs - waste of time. I'm also interested in seeing if there is any flexure, but it will have to wait until I do a neb shot.



A keen eye and a tight zoom there Paul :lol:. As it happens, you're critiquing my hasty processing. I was careless and used an action with a minimise filter step (bad Marcus!). If you want to see the raw (except for stretching) picture see:
http://upload.pbase.com/gailmarc/image/155794720/original

There is a new camera in my future too ;)

PS: I've now updated the original image to remove the processing error that caused the slightly square stars.



236mm optimally. I have a motorized secondary so I can change it. But I'd need to be careful not change the mirror spacing so much as to degrade the image.

Cheers, Marcus

[marc4darkskies]

By the way, if you want to see the gory detail (aka my ramblings) of the experience of buying and setting up the scope - see http://www.pbase.com/gailmarc/image/153663053 and download the PDF. It's only 17 pages long! :lol::help:

[Paul Haese]

That looks better on the segmented shot. Looks good. :thumbsup:

I don't mind doing 30's, I find I can go deep really quickly and then polish off the background noise by doing a few more. I don't think it is a waste of time though. Each to their own though.

Which camera are you looking at? STX I take it? The STXL is quite nice but sensor is the limiting factor I suppose.

Hmm not much back focus, though it could suit my imaging train. ;)

[marc4darkskies]

Yep, only do 30s for NB (Ha only at this stage). For LRGB I've never done more than 15 - even with the Tak and that's done me well.



STXL actually. Call me weird, but I still like the old 35 mm frame and the STX is a monster. I like the fact that you can integrate the OAG/Filters and AO-X on SBIG gear.



Yes, but I have a corrector AND a rotator :lol: If I go the STXL route I'll have surplus backfocus I think.

[Paul Haese]

The STXL is a really nice camera. I have been using mine for a couple of months or so and it is nice to image with, the integrated guide camera in the filter wheel is excellent.

I will have a read of the review., let you know what I think later.

[strongmanmike]

Looking pretty ooo-k there Marcus :thumbsup:...looks great viewed at 50% :whistle: :P

Mike

[marc4darkskies]

Aaaaand that would be missing the point entirely Mike :P Here you go then, here's a version just for you mate! WOW!! ... look how tight those stars are!! :rofl:

PS: I've now updated the original image to remove the processing error that caused the slightly square stars.

[strongmanmike]

Yeah...amazing, tight huh? Why bother with Decon, just shrink the image to suit :lol:

Mike

[David Fitz-Henr]

That's looking really good Marcus, you've made good progress learning how to collimate this beast (have you named it yet?); stars still just a tad elongated towards the upper right corner but I am being picky :P ;)

[gregbradley]

Looking very good Marcus.

You have been having a fun time commissioning the system I can tell.

Greg.

[marc4darkskies]

Thanks David - and I always appreciate your opinion, no matter how picky ;)! I know it's not perfect, so once I get an image or two under my belt (because I'm suffering major imaging withdrawal right now) I'll go back and do some tiny adjustments to see if I can remove the remaining elongation. I'm pretty sure I can. Right now though it's good enough and I can probably process residuals out.

A name? :question: :rolleyes: How about OSSIS (Officina Stellare Sensational Imaging Scope)?? Or SPOT (Semi Perfect Optical Telescope). Or BORIS (Bells Observatory Rc Imaging Scope). :lol: I dunno, you're the acronym expert - any ideas?



Thanks Greg. Yep, playing with fancy new toys is always fun!! It's been an education moving from a refractor to a reflector though, that's for sure! There's been a pinch of fear (I spent a few bucks on this thing), a smattering of frustration and a good helping of "doh!" moments - mostly as a result of my ignorance. The story has a happy ending though! :)

[cybereye]

Marcus,

I've only just stumbled upon this thread!

Congratulations on the new arrival and I hope it's been keeping you up at night! :thumbsup:

Cheers,
Mario

PS How about "Stella" for a name?

[strongmanmike]

Simple :)

MARCUS

My Amazing Ritchey Chretien Universe Surveyor

[marc4darkskies]

Thanks Mario! :) It needs to be an acronym though.



:lol: What an uninspiring name!! :lol:

[strongmanmike]

I dunno...would look good written in slanted red letters (and maybe a pin stripe) along the lower shroud ;)

[pluto]

How about:

Massive Aperture Ritchey Chretien Uber Scope

:D

[cybereye]

Stunning Telescope Exploring Luminosity Lightyears Away....Stella

[David Fitz-Henr]

Hey not bad, and he shouldn't have any trouble remembering the name :P




Nah, that sounds a little too pretentious Mike; we can't let it all go to Marcus's head - leave that to us ATM'ers :P :rofl:

[marc4darkskies]

You guys crack me up! :lol: but I don't think I'll be naming my scope after all. I'm happy to announce, however, the winner of the naming competition would have been .....



Which I find absurdly compelling!:rofl:

David Fitz-Henry, who started this frivolity without making a meaningful contribution, is eliminated. .... So, David, it's time for you to leave the Iceinspace kitchen.

[cybereye]

Yeah, I won.... sort of!

[strongmanmike]

Sigh..he's such a Bunyip :rolleyes:

[David Fitz-Henr]

Gentlemen, gentlemen ... sticks and stones may break my bones, but my acronyms will never desert me :P