The Golden Prawn - with AG12

[strongmanmike]

This is my first deepish image with teh 12" F3.8 astrograph.

After spending quite a while trying to tweek the colllimation on-camera using trial and error :screwy:and basically going around in circles :rolleyes:...I got lost so pulled the camera and corrector off and just recollimated with the Catseye tools....it's pretty close

Anyway..corner stars not perfect but everything else went well at least and after the high cloud cleared on Saturday night around midnight, I grabbed this reasonably deep image of the Prawn Nebula with just 60min each of SII, Ha and OIII...The Prawn region is not that bright really and I couldn't have gone this deep this easily with the Starfire :thumbsup:

Full frame images 1.8deg X 1.8deg field of view

Large image (http://www.pbase.com/strongmanmike2002/image/134534431/original)(use your browser to shrink it if you like)

Small image (http://www.pbase.com/strongmanmike2002/image/134534180/original)

Crops

Slight crop (http://www.pbase.com/strongmanmike2002/image/134570546/original) for a tighter composition

Just the Prawn (http://www.pbase.com/strongmanmike2002/image/134570335/original)

Tested out the dew prevention too as the night was dew laden, the AG12 OTA has a heater molded into the tube just above the primary mirror and a heater pad is mounted behind the secondary so with the three rear mounted fans sucking air down the tube all night no dew formed on the primary, secondary or the corrector, so that was a possitive - see the photos of the scope in the morning here (http://www.pbase.com/strongmanmike2002/image/134534743/original) and here (http://www.pbase.com/strongmanmike2002/image/134534735/original)

Sadly although I have resisted and hoped it wouldn't be necessary...I need an off axis guider :doh: or at least need to try stabilising and shortening my guide scope-camera setup (see above photo), 5min subs is all I can get and even that shows some trailing at times :mad2:...lucky she is big and fast! :thumbsup:...all part of the learning curve :rolleyes:

Hope you liked the darstedly narrow band colour pallet this time :)

Mike

[gregbradley]

Wonderful image Mike. Got to be happy with that. I like the tiny stars. I think apart from getting deep fast that will be a very nice aspect of these AG12 images. These fast Newts seem to get smaller stars than APOs. Lots of detail in the faint background nebula. This would be a great scope to pick up integrated flux nebulas.

Offaxis guiding is totally the way to go. You have more prospect of flex with this setup than your AP with its rigid tube and solid focuser. I tried to use a guide scope on the CDK17 and no way Jose. I just did a run of imaging using a MMOAG on the TEC180 and got rid of the guide scope. What a difference. Fabulous. Plus my setup requires one less counterweight. I saved on the weight of the guide scope, rings. Plus a guide scope makes the setup top heavy which affects balance differently at different angles. The scope is now easier to balance. The MMOAG setup I use is about 55mm thick all told with the adapters.

http://www.pbase.com/gregbradley/image/134562827/large

As far as elongated stars in the corners (not noticeable in the image really unless you super look for it) I imagine that is either a spacing issue or the corrector is not correcting all the way to the edges. I have an FS152 4 inch reducer and it starts to affect corner stars even with the ML8300 chip which is smaller than a DSLR. I could be wrong but I don't think collimation causes elongated stars at the corners. What's your experience with this? I have seen incorrect spacing cause this. I have an AP155TCC corrector/reducer for the AP140. I had it slightly off on one setup (its very sensitive to correct spacing +/- 1mm) and it caused elongated corner stars.

Greg.

[SkyViking]

What a great image Mike, the stars look pretty sharp to me and both the target and composition and colours are just wonderful. Definitely a nice achievement for the new scope I reckon.
I wonder what it would look like if you swung it over to Centaurus A and did an Ultra Deep Field... maybe we get to see that in the not too distant future :)

Although I'm sorry to hear that your guiding setup is not up to handle the new OTA it is somewhat comforting for me to learn that OAG is apparently the way to go, since I'm leaning towards the QSI with inbuilt OAG, as you know. I hope you find a solid OAG soon so you can take those deep fields :)

Thanks for the view, it looks very promising!

[gbeal]

Nice shot Mike, and good to see a few of the New Lambton Observatory as well, nice looking setup.
While I too am leaning towards an OAG, maybe you could try the finder-guider setup like I have. Converted 50mm finder, with (in my case) a Lodestar or ExView guider fitted, solidly. Mounts close in on the saddle, and is a "fixture" with the saddle and mount, regardless of the imaging scope.
Worth a shot anyway.
Gary

[multiweb]

Great prawn mate! Sizzled to perfection. :thumbsup: Good on you to brave the dew. It's driving me nuts lately. I'm interested in your primary heating system. Where exactly is it located? Between the fan and the primary or between the primary and the secondary? On the tube or the primary cell itself?

[marc4darkskies]

Yooouuuuu're baaaaaack! :welcome:

Lovely image Mike! For a NB image that is ;) ... I like the colours you've mapped - very appealing. :thumbsup:

Yeah - I reckon you need to ditch the guidescope so you can go for longer subs. You'd make some really deep images from a dark sky!

In spite of Gregs comments I'm not sure your stars are as tight as they could be given the image scale (?) Was the seeing a bit off? Maybe a bit of decon needed? Their shape looks dead on though. If anything only a slight probs at the corners but not worth worrying about IMO.

Cheers, Marcus

[Stevec35]

Lovely image Mike. Tiny stars and nice colours.

Cheers

Steve

[TrevorW]

Fine image that, and I like the colour composition

[jenchris]

When you post a pic like that, I feel totally demoralised - since not only is the image superlative, the jargon surrounding it isn't recognisable -- integrated flux nebula -- what's that, back to the future??

It is beautiful and I don't even know where it is in the sky or even if my scope can see it, which makes me an ignorant tart I guess.

[Paul Haese]

Great stuff Mike. Colour is lovely, stars on axis are very good and image brightness is superb.

OAG will help you greatly. I will never go back to a guide scope again if I can help it. The benefits out weigh the frustrations by miles.

That is not collimation as a problem in the corners. You have field curvature there. As Greg said spacing needs to be sorted. When you get that right your stars will be pin sharp all the way to the corners.

Excellent start.

[Hagar]

Great start Mike. Can't say I like the colours myself but the detail is great. A few small reflections on some of the bright stars but that is one of the bains of using filters. I can't believe the detail you have captured with just 60 minutes of each filter.
I have been playing around with a cheap Orion OAG and think this is the way to go. I now want something a bit bigger but will have to make up some adapters for whatever I buy. No one seems to make an OAG with 54mm adapters built in to fit either Atik or QHY filterwheels or cameras.
They certainly are a bugger to setup but the gains outway the problems of setup. Once you have all the spacing setup it's quite easy then. Just one focuser to worry about.
12 months back I wouldn't have contemplated an OAG and now would struggle to go back to the separate guide scope.

Keep them comming Mate. Great to see you getting some use from this new beast. Looking forward to some great RGB.

[renormalised]

Yum.....done in lemon butter!!!. Not bad for a first try of the deep fried prawn :) That 12" "astrobarbie" is a good one to throw a few prawns on :):P

[Tom Davis]

Love it, Mike! This is a great image :thumbsup:

Tom

[DavidU]

Ooooh, that's a big fat bright image. Lovely.

[richardo]

Ah Mike, this is just lovely!!
Great to get the detail and signal in so fast... aint it!!;)
Love the palette choice.... just what this area needs I reckon.
When I've imaged it, it always look very flat with BB filters, even with Ha thrown in...

I too love the small stars that the NB has brought to the image and I also like the bubble/ halos about the brighter stars.. i think it's a non issue.

For 160' worth of data.... this is very smooth and detailed!.

As for the small issues.... hell, who needs 10' plus subs, fast reflectors will do great with less:D

All in all, lovely image mate... big congrats with the scope!!
Ps love that focuser.... I've got a new Feather touch coming in a few days... think this will solve my flex issues..(every thing else is rock solid but the ML) but I did price the PDF...:eyepop:then I quickly changed websites to a more affordable focuser:lol:
'If I had money, I'll tell ya what I'd do, I go down town and by a...... hell of a lot of very very expensive astro things:rofl:

All the best for now
Rich

[strongmanmike]

I agree, I am now pretty sure the star issues is a spacing problem, must be very slightly too long or two short, probably only a mmm or two?.. not sure how t happened either as I used all the right measurments and the adpater made by OO measures up to the specs I supplied :shrug:

Yep looking seriously at the MOAG and the Mitsobusi (sp?) unit from Hutech now...I think I might just cut to the chase rather then stuff around with shortening the guide scope etc..? more money though :help:



Cheers Rolf, yes preliminary results are very promising, once I have the outer stars perfect and the guiding back to AP like standards this will be a killer scope for sure!! it's already pretty good :thumbsup: Off axis huh?...never thought I'd need it :doh:oh well at least it all seems to be on track.



Cheers Gary

May be..?..I'm just thinking if I bite the bullet and go down the off axis route to start with I may be taking those 20min subs at F3.8 :eyepop: a little sooner :D



Thnaks Marc

The heater strap is molded into the tube in-line with the primary mirror.
You can see it here at the back of teh tube (mirro removed) http://www.pbase.com/strongmanmike2002/image/132998033/original


Glad you liked it, couldn't let you have ALL the glory with that mediocre TOA shot of Cen A :whistle: :thumbsup:

Agree re the stars but I think they are close: http://www.pbase.com/strongmanmike2002/image/134190322/original
;)

But as you say the seeing wasn't perfect either.



Thanks Steve so far on track :thumbsup:



Thanks Trevor, colour was thought about very carefully this time after the Eta trials :P



Glad you enjoyed the vire Jennifer :thumbsup: this nebula is right near the first bend in the Scorpions tail :)



Cheers Paul, as I have said above, agree re the stars just had to play a process of elimiation and collimation tweeks don''t improve or evn chnage it so it must be the spacing :question:



Thanks Doug, appreciate your considered comments and I think I agree with them :thumbsup:



Thanks Carl, yeh it looks like buttered prawns huh? :thumbsup:



Cheers Tom, not quite an AP RH :eyepop: but once tuned I think the AG will be formidable too and a geat dust buster..? :thumbsup:



Cheers Dave, fat man - fat nebula :P



Thanks so much Richard, we are brothers now :love2:...must get that OAG though, imagine 20min subs with 12" at F3.8 under a dark sky...the mind boggles :)

Mike

[John Hothersall]

Thats a wonderfully rich image and would love to see Centaurus A given the AG treatment. Star halos come from the OIII which is Astronomiks worst offender for halos with mirror scopes, there new low reflection Ha filter was not as bad but the OIII showed little improvement.

Hopefully you'll have a good winter and an OAG will give you those long SII exposures some objects demand. Lodestars are difficult to get as SX seem to be struggling to supply so you'll need to reserve one with the Australian dealer (663AUD).

John.

[strongmanmike]

Cheers Johnny

Thanks for the compliments on the image, I'm getting there...
Thanks for the tip re the Loadstar ...I do have the SXV-H9 though and while a bit bigger in the body than the load star it is still pretty small so I am hoping it will be suitable - much better little camera :thumbsup:

Mike

[sjastro]

Very fine image Mike.

Steven

[gregbradley]

I wonder if there is a way to tell if you need to space it further out or closer in? Perhaps CCD Inspector
Greg

[Doomsayer]

really promising Mike - I had little success on the same night in newcastle at shorter FL - seeing was pretty ordinary so that makes your image even better. Very tantalising prospect to go deep with ths rig as you say. I'd imagine getting an OAG in the train is not plug and play. Another pair of special adapters on the way I guess.....

as said elsewhere, the MMOAG is a good one to consider. very solid.

guy

[strongmanmike]

Thanks Steve ...there is better yet in her I am sure :thumbsup:



My thoughts exactly...some emails will go out ;)



Hey thanks Guy, so far things are on track at least :prey:...had I not had the perfect correction of the Starfire drilled into my brain I would probably be over the moon with these stars :lol:, they aren't bad but obvuiously when it is sorted they can only be better :thumbsup:

Sorry to hear you ahd bad weather your way or did you mean you had probs with the gear?

Mike

[Doomsayer]

No gear issues here - the FSQ rig is fine - just persistent thin cloud. Better than the more normal rain or cloud on the coast we seem to suffer most of the time. Hence my RC will hopefully be on line soon in darker skies with better weather. I use an ST402 and an e-finder with the FSQ. Maybe you could consider something like an e-finder, rather than an OAG, as an e-finder will cope with 2m FL guiding no problem with the NJP.

[Peter Ward]

Very nice image! ....my guess is it will have a $15 entry fee attached to it :)

[bmitchell82]

Love the details in the image Mike although the colouring isn't up my ally. 12"s of love really has its place in my heart though :P. As for OAG, it will be the best thing you ever invest your $$$ in the difference is unbelievable! to say the least.

I Just finished making my 3" version that screws directly into the draw tube of the 3" FT and my images went from wobbly stars to perfect guiding instantly and of all things a lowly EQ6. I have some comparisons of Guide scope to OAG on my blog if you scroll down, plus there is images of the process though making it. Good luck!

[Bassnut]

Excellent Mike. Tight as and very detailed.
Do homework on OAG, cant see you need it based on this pic. The MOAG takes 50mm , seems you have 79mm back focus to the image plane total. OAG is a pain without a rotator. All looking a bit difficult IMO.

[bokglob]

Thats impressive narrowband considering your exposure time and short subs. Looking forward to seeing what you can achieve with this new setup you've got:thumbsup:

[avandonk]

I would be working out a way to control the anti dew heating of your optics. A very good thermostat or PID that only allowed heating to a few degrees above ambient would be a start. The differential cooling/heating of the metal and glass in the last part of the optic train with ambient temperature fluctuations would make adjusting spacing a nightmare. You are forever chasing a changing configuration. Fast optics come with a price! I would go for a thermostatically controlled temperature using a PID (proportional integral differential) controller. Air currents due to convection in the last part of the optical train are not as critical to aberration. Multi element correctors and spacers will come to equilibrium with constant temperature.

Just a few thoughts Mike. I am not as mad as you think. It would be a set and forget as the conditions are under your control. Not driven by the vagaries of ambient temperatures and all the hystereses that hides the real cause. Have a yarn to the manufacturers as they just do not realize what huge temperature fluctuations we experience here in Australia.

I will not comment on your image as it is not too bad for a beginner with a new optic.

Bert

[Octane]

Dribble.

Superb image, man. And, for such short exposure duration, too. I guess we have to bear in mind that it is an insanely fast scope, too. :)

Looking forward to more from this winning combination.

H

[atalas]

Yep looks great Mike.

[strongmanmike]

I am (temporarily) set up in New Lambton now and yes the thin cloud started to disipate as midnight approached so I went for it .What is most pleasing is that I was able to get a multi filter image down that went this deep, in the space of just 4 or 5 hours including flats and flat darks for every filter and even a meridian flip in the middle. This was the leap I wanted over the beautiful Starfire :thumbsup:

An e-finder huh?..hmmm? Tom Davis seems to think it is quite good for his AP 12" F3.8 for at least 10min exposures :question:...of course the OAG should allow indefinite exposures...ahhh decisions decisions...:sadeyes:



Thanks Peter..?...I dunno, David probably won't like it...at $15 a pop one must choose wisely ;)



Glad you liked it Mr Mitchell, I'll check out your blog..but as Fred says below they can be a pain too.



Oh I need something, 5min was showing regular trailling, however when the two scopes pointed overhead it improved (sure sign of diff flex) look at how long the end of my silly guide scope is though, best at least improve there...deffinitely need to do something, I want to be able to do 15 - 20min subs but as you say, I will deffinitely do some homework, cheers :thumbsup:

Mike

[telemarker]

Hey Mike,
A grand colour scheme for a narrowband christening. Sweet :thumbsup:

Obsequious Prawn was very forlorn
and didn't know what to do.
His reason to fret ?
He'd been caught in a net,
and was heading for somebody's stew!

I'll echo the comments of the others, it's looking good.

Regards
Keith

[Star Catcher]

whoa! Mike that is a great field and love the detail you've captured with the scope

Ted

[Paul Haese]

Mike just looking at the star images all are pointing towards the center and I think these are all pretty much the same length. That means that collimation is less of an issue (maybe just a really really small tad if anything at all) and being pointed to center it is pretty certain that field curvature is the culprit there. I spent a heap of time on this very issue a year or so ago now. Learnt what to recognise. I guess you can narrow it all done if you want but I think going straight to the spacing will do something more for your stars. Just my opinion. I am sure you will nut it out. Let me know though once you find the culprit.:)

[Bassnut]

Ive banged on long and hard about guider stiffness, that maybe the key, makes ALL the difference. Anyway, PM me if you have backfocus limitations that make OAG impracticle.

[h0ughy]

Nice tiddler Mike - i take it you will be out tonight moon and all as it is clear in newcastle tonight..........

[avandonk]

Bolt a lightweight Mak to the scope at the rear Mike as a guidescope. The short configuration of the Mak will minimise 'flexure' with orientation.

Bert

[strongmanmike]

Thanks for the advice Fred, Bert and Paul appreciate the feedback and ideas :thumbsup:

Thanks also Keith and Ted, nice poetry Keith ;)

Dave, I am about to go to bed, yes it is clear but I have been up late two nights in a row processing the Prawn :rolleyes:..so I am a bit tired, Thursday is looking good so fingers crossed I can get out and get another take-away instant deep image :thumbsup:

Mike

[strongmanmike]

Cheers Humi Darell and Big Louie, glad you liked the scene

Yes the aperture and speed were exactly why I went this OTA route ...once I have the field flattness/stars perfectly sorted and the guiding under control the sky will literally be the limit :thumbsup:

Mike

[alan meehan]

Just beautifull Mike really sharp and lots dust,love it
AL

[bmitchell82]

they can be a pain in the arse when you don't have the right set up from what i have seen. I have not hit a snag yet and its not even focused to the main ccd, I will post up what im guiding on so you can pee yourself laughing! but hey its representative of the stars and if it moves it corrects and the stars are round. :) your setup is just a wee bit better than mine :) so you shouldn't have a issue.

[strongmanmike]

I had a look at your OAG - very nice job...I couldn't see much difference between the before and after photos though :shrug: so I must have been looking at something else..? :question:

I want to go down the OAG path but I need to nail the correct spacing first so I know what Orion needs to make me exactly.

Mike

[bmitchell82]

Non OAG
http://brendanmitchell.net/wp-content/uploads/2011/04/Non-OAG-guiding-animation.gif

OAG
http://brendanmitchell.net/wp-content/uploads/2011/04/OAG-guiding-animation.gif

Like i said this is the white polished turd at work with massive PE at best!

This is what OAG has enabled me to do

http://brendanmitchell.net/wp-content/uploads/2011/05/NGC-6729-120_25_25_30.jpg

Vs This

http://brendanmitchell.net/?page_id=10&album=2&photo=126&occur=1

Its worth the screwing around but yeah at the moment im guiding not on banana stars but comets with tails! :)

[multiweb]

Interesting to see it's fitted under the lining. Is it bulging or coming off the wall with the heat or do you regulate it so it's just warmish? So I understand it just warms the primary glass by proximity? Doesn't transfer any heat to the mirror by touching it right?

[strongmanmike]

The broad pad is molded onto the inside surface of the tube. It is designed to gently warm the air in the area in fornt of the mirror, warmer air can hold more moisture and thus slow or prevent the formation of dew, the moving air caused by the rear fans also helps here too and produces a laminar air flow .

Mike

[strongmanmike]

OK I didn't look at your pages properly (I was at work) those results are quite telling....

I guess you haven't been using it for long but so far how easy has it been to find a guide star..?

More thinking to do :question: :help:

Mike

[mill]

Very nice Mike :)
Love the color and sharpness of the picture.
Gotta love narrowband :P
On the subject of off axis guiders, sometimes it is a pita to find a good guide star :(
But normally you would find one good enough.

[bmitchell82]

If you run a high quality guide camera, for example SX Lodestar and what im using at the moment is a SBIG 402-me, I haven't had a issue with finding a guide star yet. If worse comes to worse run it at bin 2x2.

And yes I have only just finished it mid last month, but I am convinced that it works as described and kills all flexure which big newts are renowned for. The thing that will make it hard for you is the back focus from the whynn corrector and fitting everything in between that and the sensor.

[strongmanmike]

No worries there I use an SXV-H9 and it is excellent, very small and compact.



Yes but I thiiiink I can squeeze one in...? :question:

I'm going to try stiffening up my guide scope first..then, we'll see :)

Even consitent 10min with 12" at F3.8 would go very deep :thumbsup:

Mike

[Phil Hart]

Did you allow for the optical thickness of the filters and ccd sensor glass when you calculated all that? As I recall, if you have a filter 2mm thick that's only equivalent to 2/3 the amount of air.. say 1.3mm. If not you could move in by 1mm and see if that helps? Or maybe you figured all that already.

Your extreme corner stars are the same shape as mine on the Tak E160 f3.3.. but I'm using much smaller sensor. Tweaking spacing may help but you may be close to the limit of what you can achieve at f3.8.. it is a compromise after all!

And I understand what you mean by going round in circles trying to collimate using the camera.. you make one tiny adjustment and then the star has moved and you have to be looking at a star right in the centre of the frame so then you have to recentre.. blah.. impossible i say! i gave up too..

Phil

[bmitchell82]

well like i have shown, since doing that mod, its been keep 3 out of 12 odd images because of bad guiding and even those images where pretty average. now i keep everything bar the meridian flips images :D.

Im even going to start moving out to 15 min Lum and possibly 10min rgb because of the confidence i have with it now.

[strongmanmike]

Hi Phil

I extended the distance 1mm (with a gasket made from plastic bucket lid :P) and the corners are deffinitely better :thumbsup:..so it (predominantly)wasn't a collimation issue, hence the going around in circles when collimting on camera :rolleyes:. Yes the 16803 sensor at F3.8 is a challenge but worth the trouble I think. The design of the fast Newt, even with mega bracing, is pushed to the limit with a camera like the PL16803 and CFW-5-7 attached!..variations in star shapes across the sky as a result of tiny amounts of flexure is probably inevitable and hard to eliminate 100%..? In the end the massive field of view at good image scale with a high incoming flux density were the two main reasons for going down this route - I have a Starfire after all and that is hard to beat for imaging resolution :thumbsup:





If you read this Brendo I am up now so ring me! :)

Mike

[gregbradley]

Interesting Mike. So that means you need to extend out further. I got some spacing rings from Astrodon for my MMOAG. Each one is 5mm. Something like that would be handy as its all black anodised aluminium and slides over the threaded fittings to pack it out the right distance.

If you experiment with any sort of packing material and get the exact distance you could then get a more permanent solution with one of these rings made up. Moog could probably make one for you cheaply or Precise Parts - more expensive but its correct every time.

Greg.