New System a Start for Assembly [Archive]

Paul Haese

24-03-2012, 07:22 PM

I have to ask Bert, what is the deflection like with that pier? To my mind is the idea that the pier of that size would deflect considerably. Perhaps I am wrong, but with the gear you have on board there may be some and that might be a problem you will need to sort later down the track.

That aside I am glad to see you getting the new gear altogether.

avandonk

24-03-2012, 09:01 PM

Thanks for your concern Paul. Here are a couple of images of the pier. It just does not deflect or have nasty harmonics.

The eight bolts at the bottom allow the pier to be adjusted level without any extra stuff at the top. This gives about 2 or more hours past the meridian so no flips are needed.

The four almost full length tapered gussets ensure that there is no bending at the base. This is where the bending moment is at a maximum. A pier can be considered as a vertical spring pendulum and will have a harmonic frequency depending on load and stiffness. The taper gives the system a low 'Q' so any high frequencies from mount motors or fans will be damped.

I have had about 40+ kg on the EQ6 without any problems. It was SN10 with a focal length of 1150mm.

If I do notice any flex I will just get a new pier made with a larger diameter tube.

Bert

Paul Haese

24-03-2012, 09:43 PM

Yeah tapered gussets is what I have on the pier down at the observatory. That all seems to gel and now that I can see the gussets that changed my mind considerably. I did not see those before. Thanks for pointing that out.

Mighty_oz

24-03-2012, 09:44 PM

Tiss a thing of beauty there Bert :) Be nice to see it all working. Are u going to run the cables thro the mount ?

cventer

25-03-2012, 11:36 AM

Bert

Looks good bert.

What side by side setup is that ? Looks very interesting.

Where did you buy this setup ?

gregbradley

25-03-2012, 11:54 AM

Great looking mount and setup.

Your mount seems more red than mine. Mine is more of a pink/red. I read there were some problems with the anodising with some early models so perhaps they either changed anodisers or changed colours slightly. Unless its simply the white balance in your camera.

Greg.

avandonk

25-03-2012, 01:18 PM

I got it from here Chris

http://www.starstuff.com.au/

Luke Belleni from Starstuff made the side by side. It is very robust and very well made. I have never seen flexure even with a Meade 10" SN on the EQ6.

He has a PME himself and has designed a double dovetail bar that fits into the standard versa plate of both the PME and PMX. You will need to rotate the versa plate by 90 degrees to get full mount travel.

He is helping me by making all the bits I need to set up the new system. He is not cheap but that is because it is high quality equipment. He is based in Melbourne and is quite happy to design custom equipment.

Well worth a look. If you like I can put up some images. He has good images on his site.

Bert

avandonk

29-03-2012, 10:30 AM

A bit more progress. The mount is now controlled by the software. The correct coordinates and hemisphere have been set. I actually read the manual to get this far or when all else fails RTFM! Luke Belleni showed me how to get started. Although we could not get far as it was very cloudy.

The pier has been accurately levelled with a builders level and the small level on the PMX agrees with it. I have just put my finderscope on for the present which is a F1.8 16 to 160 mm Canon zoom with GstarEX camera. This will make a 'rough' polar alignment far easier.

I sent the mount over most of my visible sky and the objects selected for goto did appear on the finderscopes screen at low magnification.

It is obvious to me I need to play with the mount alot more before I fully understand it. The sophisticated features of the PMX are too numerous to understand quickly or easily.

Any advice gratefully accepted.

Below are a few images showing more detail of the side by side and the finderscope.

Bert

Paul Haese

29-03-2012, 09:31 PM

Bert to get pretty accurate polar alignment, follow the rountine using the SkyX. That is select a star and tell the mount to slew and when it stops move the mount in az and alt. That gets you pretty close to the mark. Then do a Tpoint run and follow the Tpoint recommendations to move the mount.

avandonk

30-03-2012, 10:23 AM

Thanks Paul.

I have set up a 100ED with a GstarEX as well as the finder. Cloud last night stopped further progress.

Yes another four leads trailing but this is only temporary. I am getting to old and lazy to chase an eyepiece around on a goto mount.

The sky finally cleared early this morning and I spent some time accurately aligning the finder with the 100ED. This means I will be sure that the star in the field of the 100ED is the correct one when it comes to adjusting altitude and azimuth of the mount.

Dawn arrived before I could start to do a 'rough' polar alignment.

This gives me another day to try and ingest the information in the manual.

Bert

DavidNg

30-03-2012, 11:54 AM

Hi Paul,

After doing a TPoint run and following the TPoint recommendation to do polar alignment adjustment of Az/Alt, do we have to run the Skyx as if "from scratch" again? ie sync with a star and adding sample points again? I did follow the mount Az/Alt adjustment, however the scoping pointing was still miles off. Thanks in advance
David

avandonk

30-03-2012, 12:27 PM

I was going to first drift align the mount and see what happens. It is facile to just adjust azimuth and elevation of the mount on one star as it depends on where it is. It is all about othogonality or independant variables.

You can adjust azimuth on a star near the meridian and it will not move. Conversely adjust elevation on a star near either E/W horizon and it will not move.

Drift alignment is the opposite of this.

Bert

DavidNg

30-03-2012, 12:47 PM

Hi Bert,

I am new in every aspect of astronomy. After spent many nights and tens of hours of drift alignment following often contracted instruction from webpages, I managed to have fairly still star on illuminated reticule over more than 10 mins at both North/equator star (for Azi) and West (for alt), from then I tried TPoints run, quite accurate on almost every slew....then the trouble, I followed the Tpoint recommendation to adjust the mount azi/alt (off over 100arcmins), back to SkyX...every star slew is far far off...My drift alignment and TPoint seemed fighting each other. Please help... I want to get this alignment business over and go on to do other more interesting things..

David

cventer

30-03-2012, 01:56 PM

Gents

Provided your location (LAT , LONG and time) are correct then you can rely on T-Point to tell you how to Polar Align.

Homing the mount first syncs the mount to where it should be. Delete all syns in bisque TCS then just point to a star using SkyX somewhere between east and due south above 45 degrees but below 90.

The scope will get close to this without a full model. Use the mounts ALT and AZ settings to center the star you just pointed to. This will get you within a few arc mins.

Once done then send mount home again. Now start your t-point polar alignment run. Move to a star again center it in cross hair or CCD and sync (better still take and image, inage link and plate solve it) then sync on the photo. You then go into t-point add on and add about 9 - 12 more targets all on same side of meridean. then click supermodel button. It will calc your offsets and tell you which way to move the PMX knobs. This will get you to sub arc min.

Once you have don this once you then need to delete the t-point model and the sync and start again. ie send mount home, slew to a star, sync, then start another 12 points t-point run. Follow instructions again on knobs.

If you start to oscilate. ie one run says move 2 tics then next says - 2. Then half what it tells you. So if it says 2 ticks west. Do 1 tick west. Eventually it will report no more adjutsment needed and you are done.

its fast and accurate. No need to drift align anymore. :):D

avandonk

30-03-2012, 02:32 PM

Thanks Chris

When all else fails I stick to what I know!

bert

CDKPhil

30-03-2012, 02:34 PM

Hi David,
If you use T point to do a polar alignment it will align on the refracted pole.
My procedure for a portable set up is as follows.

Get a North South line via a shadow when the sun transits the meridian.
you can get the transit info from Sky X. Make sure your long/lat, time and date are correct for you location. This should get you in the ball park of true South.
Adjust the PMX altitude to match you latitude.

Home the mount.
Make sure you clear any existing Syncs and T point Model.
Slew to a star that is within 5 degrees of the Pole and 5 degrees of the meridian.
Do not use any controls. To centre the star, only use your altitude and azimuth adjusters.

Once this is done I home the mount, then slew to a bright star near the equator, centre it and sync on it.

Form here I do a new T point calibration.
Start by selecting stars that are near your sync star. After about ten to 15 stars I swap to the other side of the meridian and do the same.

Press the Super model button.
I then check the polar alignment report. and make the adjustments that it recommends.
After the adjustments, I home the mount, clear the sync and the T point model, re select a bright star near the equator centre it and sync on it.
Then I do another Tpoint calibration run. This time I do about 50 stars and re check the polar alignment.
Every time you adjust the altitude or azimuth you must clear your existing sync, re sync and redo your Tpoint model.

A few nights ago I ended up with 9 arc second pointing after doing this procedure. (That was after 150 points.)

I hope this helps.

Ps I had already written this and I noticed that Chris had already posted an answer. I thought I would post it anyway. It pretty much says the same thing.

Cheers
Phil

DavidNg

30-03-2012, 02:43 PM

Many thanks for your advice cventer. On page 67 of the The Paramount MX user guide (step 7 of quick polar alignment) recommends to chose a "bright star within 5 degrees of the pole or 5 degrees from the meridian", looking through the eyepieces, I would never be able to identify correctly such star. Can I use any star as you have described?

Thanks

DavidNg

30-03-2012, 03:07 PM

Thanks Phil,

I will try again if Sydney clouds clear up. More questions please (I have so many).
Once you have the polar alignment greatly satisfied, does your mount atl reading agree with your location site? eg.. 33.6 for Sydney. And sometime the SkyX will not slew to particular region with slew limits error. Is there a way to overcome the limit restriction? and if so will it cause any damage to the mount/scope?
regards
DAvid

cventer

30-03-2012, 03:14 PM

Pretty much. Choose something thats more south. ie somwhere between se and south is fine. and anything above 45 degrees and this will get you close enough. if you can get higher ie between 60 and 90 degrees than thats better but dont agonize ovr it. Its just to get you close. before your run the t-point model

tilbrook@rbe.ne

30-03-2012, 03:15 PM

Hi Bert,

That's some precision gear you have, can't wait to see the results from it!

Cheers,

Justin.

Paul Haese

30-03-2012, 03:47 PM

Thanks Chris you got the questions before I did. Besides I am still using sky6 which is a bit different from Skyx when it comes to Tpoint modelling.

Bert using Tpoint is a necessity anyway because you will want accurate pointing for the imaging you want to undertake. Using Tpoint now will get you down below 10" and is repeatable everytime. When I do an image now I can rely on landing at the same spot every time. That makes mosaics easy too.

If you use the description that Chris just told you your mount will be setup and ready within a couple of hours and that includes a 150 or so tpoint model.

avandonk

30-03-2012, 04:21 PM

Sorry if I got my/your wires crossed. I did not want to rely on setting up the mount with a pure imaging system.

My aim was to have the mount aligned before I put on the optic and camera etc for imaging. I am well aware that images solved by tpoint and plate solve etc will give a very good model for the sky.

I am of the old school that knows where every major object is and to get to it we do it manually.

My aim was always to approach this very carefully. I still find it disconcerting when the mount decides to do a meridional flip when the new object is very close but over an imaginary line.

I also wanted to have a full understanding of what was really happening and not just make do because it works or it is easy.

This will save me many frustrating errors down the track.

Bert

CDKPhil

30-03-2012, 05:10 PM

The altitude of my mount is very close to the site latitude.

The slew limits are there for a reason so your OTA doesn't hit the pier or tripod.
If you look on page 109 of the user guide it shows you how to adjust the slew limits.

It might be a good idea to start another thread with all of your questions?
Even a Sticky, PMX Q&A

Cheers
Phil

frolinmod

30-03-2012, 06:10 PM

Don't make it harder than it has to be. There's really not much to it and it's not difficult either. The learning curve is short and sweet and then you'll either be an expert or think you are. :P

gregbradley

01-04-2012, 07:18 AM

Hi David,

If you adjust the mount's Alt Az using the polar alignment directions from T-point then that model is no good anymore because things have changed.

You have to delete the model and do a new T-point model.

I'd have to read the manual on this point again as you may also be able to do a synch on a star to realign the model after adjustments with the Sky X.

Fortunately its a superbly written manual.

Greg.

avandonk

01-04-2012, 09:44 AM

After a bit of encouragement from Mike S. I had a go at assembling the image train.

The total distance from the back plate of the RH200 to the focal plane of the camera is 109.1mm. The Atlas focuser is fully retracted. The focal plane of the RH200 is 115mm from the back plate. So focus is within the range of the Atlas focuser which is 9mm.

Once the Altlas focuser is extended the three screws that hold the zero tilt adapter can be loosened and the orientation of the camera and filter wheel can then be reset.

Looks like we are in business.

Bert

Peter.M

01-04-2012, 10:21 AM

I love the fact that the camera and filter wheel dwarf the scope in physical appearance. Engineering brilliance.

Paul Haese

01-04-2012, 10:53 AM

That filter wheel is huge. I wonder if that will create the need for a counter weight offset. :question:

Once you get that scope on the mount and doing a Tpoint run you will be mesmerised by the beauty of the thing.

avandonk

01-04-2012, 11:08 AM

Paul I will have the finder and 100ED as a guide scope either side of the RH200 so the whole lot can be easily balanced.

I opted for the ten position filter wheel since I have 3nm NB filters I will need a [NII] NB filter as well. The red continuum filter is another reason.

see here

http://www.iceinspace.com.au/forum/showthread.php?t=87708

It looks pretty good just sitting there!

Bert

Paul Haese

01-04-2012, 11:32 AM

I certainly see why you wanted to include those filters. Large scale projects with multi banded images are very interesting and add flavour to any image. With any luck the finder will offset the weight, but I think you might have to put something on the front in the opposite position. Often getting balance can be difficult and the one thing that the SB mounts require is very good balance. You should not have the counter weights on the RA offset at all. Perfect balance is the goal. I don't think it will be a problem, just something to bear in mind if you cannot get DEC tio balance out perfectly. :)

Yes it does look pretty good just sitting there.

avandonk

02-04-2012, 10:04 AM

Paul the filter wheel can be easily oriented with the bulk vertical to the DEC axis. I do not see any problems.

Bert

avandonk

02-04-2012, 10:17 AM

Had a play with the mount last night for the first time without any cloud. It is stunningly stable. I thought my belt driven EQ6 was stable and had very little backlash the PMX is far better.

I did a quick drift align as it is something I am very familiar with. I then went to the home position and then slewed to a star and synchronised, the PMX went repeatedly to any position in the eastern sky. It was off in DEC in the western sky no doubt due to the geometry of the scope(s) not being exactly orthogonal to the EQ axis.

Bert

Paul Haese

02-04-2012, 10:29 AM

My thinking is that at some point you will want to rotate the camera. Do you have a rotator between the filter wheel and camera. If so this will not present the problem I have suggested. However, if there is no rotator involved then when rotating to get the framing you want will result in the filter wheel being moved to another position and creating balance issues. This is because the camera and filter wheel tend to move as one and you rotate this assembly around the axis of the telescope.

Most often the rotator goes between the telescope and the filter wheel.

I hope that makes sense and you can see what I am talking about.

In any event you need that size filter wheel and you will either find it problematic or not. Just thinking ahead a little for you. :)

avandonk

02-04-2012, 10:39 AM

Paul I want to do mosaics so having the camera oriented in the DEC and thus RA is essential. The field of this setup is 3.5x3.5 degrees. Rotating to fit in an object of interest is not even on the plan.

The side by side I have is fully adjustable (all possible degrees of freedom) to get perfect static balance. It is also very rigid and orthogonal.

Bert

Paul Haese

02-04-2012, 10:43 AM

Yes I see what you are trying to achieve. :)

avandonk

02-04-2012, 04:15 PM

Just ordered the 50x50mm 3nm NII and 5nm red continuum filters. This is not an exercise for the faint hearted as just the filters have cost $7k Aus. Looks like it is baked beans for another few months.

Bert

avandonk

07-04-2012, 12:43 PM

My mind was becoming numb to ,the point of paralysis with the thought of everything I was trying to understand with both the hardware and software.

I have managed to polar align the PMX with T-point. Just like everything it is easy when you finally know how to do it. As usual clouds were trying to spoil things.

This morning I fired up the Atlas focuser and IT's ALIVE! I can now remove the Zero Tilt Adapter to finally assemble the image train in it's final orentation.

The adapter Luke Belleni made for me is now matte black inside to minimise scatter.

The NII and Continuum filters arrive on Tuesday as I just paid customs and GST on them.

Should see first light on about Thursday if the weather report is correct.

Bert

Paul Haese

08-04-2012, 10:20 AM

Excellent Bert, Tpoint did seem daunting the first time I used it too, but looking back now it seems relatively simple compaired to other automated sequencing. How did you go with your pointing in the end? I recall some of the other PMX owners got theirs down below 10" of arc for their pointing.

avandonk

09-04-2012, 05:29 AM

Paul I set up my finder and the 100ED (both fitted with GstarEX cameras) to point at exactly the same place in the sky. This way when a star is in the center of the field of the 100ED 24' X 18' it is also in the marked field center of the finder of field 22 X 17 degrees. This way I am sure what I star I am using to add to the calibration run.

I roughly aligned the polar axis by drift aligning. Then did a calibration run only on the Eastern sky.

Result is image one below.

I then adjusted the mount according to the numbers that Tpoint gave me for azimuth and elevation adjustment. Then I did another calibration run.

The result is image two below

The improvement is remarkable.

If only the clouds would go away I think I can do even better. It is difficult learning new methods when weather interrupts.

Bert

frolinmod

09-04-2012, 06:17 AM

Wow, I don't know why I didn't notice it before, but I just now noticed that beautifully functional side-by-side plate setup. That looks much more straight forward and functional than the ADM Accessories equivalent. Nice!

avandonk

09-04-2012, 07:09 AM

Yes it is very rigid and easy to adjust for balance. All dovetails are gripped by the full length of the clamping bits. So very little force is needed for a secure adjustment.

In the picture below you can see the bit that slides sideways (dovetail plate) without a dovetail bar for a scope. The clamping on the main bar is controlled by the lever which has a rachet mechanism so the lever can be parked out of the way.

Luke Belleni of StarStuff made it for me. You can see his products here.

http://www.starstuff.com.au/

and here

http://www.starstuff.com.au/eqsbskits.html

He also made the double dovetail so his side by side fits directly to a Paramount ME or MX Versa Plate.

Bert

Paul Haese

09-04-2012, 03:27 PM

Next step is to get the camera doing the run and taking around 200 points for final pointing to all parts of the sky. You will still get it to around 9" for pointing and then you can use the sky function to map and plan out your mosaics.

Looking good so far.

avandonk

12-04-2012, 12:21 PM

Recieved the last two filters yesterday. I assembled the whole system last night.

Everything works and below you can see a sky flat taken with the 3nm HA filter this morning. The camera was at ambient. I do not think that 3nm NB will be a problem with this fast F3 system as predicted.

You can now see the almost perfect colour match between the PMX mount and RH200.

First light tonight and I will stick with the program and do some 3nm HA and NII of the Carina Nebula.

I having a cold one after all of this strain.

Bert

CDKPhil

12-04-2012, 12:57 PM

Looks like you have been very busy.
I hope the weather is ok for you tonight.

Cheers
Phil

cventer

12-04-2012, 02:29 PM

Bert

Looking good. I would suggest you do something however with all those cables. A mount hub pro will help you remove most of that cable clutter.

You can use pre wired internal cable to run 12 volts to mount hub. You plug mount hub USB into one of the USB plugs on the back of the dovetail panel which is also then internally wired. You can then connect your dew heaters, your atlas focuser, filter wheel and into the mount hub USB hub. You connect your proline to the 2nd usb port on dovetail panel. You can then control it all from the one USB cable that connects the mx to your pc. This includes individually setting different dew heaters temps and remote control of power on USB hub for any fans or cameras and filter wheel power.

I have this setup on mine and it works great.

avandonk

13-04-2012, 04:23 AM

Thanks Chris and Phil, at the moment I am using the cables I have. Once everything is working and it seems to be will tidy up all the cables. Where does one get one of these mount hub pro.

Looks like the adapter that Luke made is a bit too thick. We need to go in further to get focus. We did expect it as it is easier to machine off metal than to add it.

Below is a couple of out of focus images of Carina. First is taken with 3nm HA 120s. Second is 3NM NII 120s. Both autostretched in images plus. Looks as if about half of Carina's HA is really NII. What happens at the fine detail level should be interesting.

Note that the star annuli show very little vignetting near the corners. You can also get an idea of the field of this system 3.5 X 3.5 degrees.

Luke is machining the adapter today. I also ordered a Lodestar autoguider that should arrive today. Tonights the night then. :)

Bert

Paul Haese

13-04-2012, 09:32 AM

The mount hub pro can be purchased either from the Australian distributor (http://www.sirius-optics.com.au/)or through the manufacturer (http://www.hitecastro.co.uk/index.php?option=com_content&view=article&id=48:mount-hub-pro&catid=36:mount-hub-pro&Itemid=54). I have two and had one adapted with breaks and connectors in the cables only 6 inches from the unit. That way I could put the cables through the mount and change the telescopes off easily without having to find a place to store the hub. It cost me about 30 pounds more to get that done but it works well. Each telescope has its own hub. These things are worth the money and I recommend you get one. It carrys a lot of options from USB ports to power and focusing ports. Very good idea.

Things are looking good but I still think you need an OAG rather than your current guiding solution.