(member)

07/04/09 01:13 PM

rube goldberg M31

Just getting started connecting my DSLR with my telescopes, and I think I could learn to like this. My son and I sat in the back yard taking this session with M31, and the equipment arrangement reads like a Rube Goldberg contraption.

We used my AT66 ED for imaging (64 shots, 30 secs each, unguided), and this telescope was piggybacked onto my Ultima-11's already-overloaded mount. Every breath of wind makes this arrangement move, but luckily, we had little wind on July 2-3, so the frames came out fine.

But 30 seconds was the maximum we could manage from the mount, as it's barely up to visual imaging, so anything longer constitutes pushing one's luck.

This was stacked and stretched in Nebulosity, and except for a bit of red gradient that I have to learn to get rid of (M31 was situated right above a neighborhood sodium vapor street lamp), things turned out pretty well. The moon was up, the wind kept threatening to shut us down, and high clouds periodically obscured most of the sky, but so far, so good!

Constructive comments and suggestions are appreciated. This is only my second full night of digital astrophotography, so I can use all the help I can get (well, that and a GEM, too!).

(member)

07/04/09 01:15 PM

Re: rube goldberg M31

Probably ought to attach the image, too... sorry about that!

(Post Laureate)

07/04/09 02:30 PM

Re: rube goldberg M31

Nice round stars - nice galaxy. Not bad at all!

But you are right - you won't get much further without a better mount as you really need exposures upto 5 minutes to get teh faint outer reaches of the galaxy arms.

You have a good set of data for the bright bits - keep them and combine with stuff you get when you can go longer

I recon with the stars as round as you have them, that you might get lucky and have success upto 1 minute

Only critique I can offer is that you have lost colour somewhere in your processing. Ther are nice orange stars in this field and you don't have them

(member)

07/04/09 03:13 PM

Re: rube goldberg M31

Tony:

Thanks for the words of encouragement, and for this:

Quote:

Only critique I can offer is that you have lost colour somewhere in your processing. Ther are nice orange stars in this field and you don't have them

I do minimal processing, and don't touch the color adjustments in general (I'm new at this, and prefer to confuse one issue at a time). But the first step in all of my Nebulosity processing is the "adjust color background" process, because there's plenty of sodium vapor lamps near my house, and their color pervades almost every image taken hereabouts.

So I'd wager that the orange and yellow colors in the images are disappearing as collateral damage from the removal of the local light pollution. One of these days when I pick up a real mount for my nascent astrophotography attempts, I'll get out of town to some darker skies away from all these orange-colored streetlights!

Is it ok (given your location) to wish you a happy Independence Day?

(Carpal Tunnel)

07/04/09 04:59 PM

Re: rube goldberg M31

I think you did a super job for 30 second subs and all else you had to contend with. You can see some nice dust lanes in towards the core, and you held up the blue tone in the outer arms. There's a lot you can shoot with 30 sec subs, especially if you speed up the WO 66mm with a focal reduer/corrector. But even without, just shoot gobs of subs, and choose bright targets.

And I'd have to pay my son to sit with me through an astrophotography session.

So fine job to the both of you!

(Post Laureate)

07/04/09 05:01 PM

Re: rube goldberg M31

Quote:

So I'd wager that the orange and yellow colors in the images are disappearing as collateral damage from the removal of the local light pollution.

No - this won't be the case as LP colour cast removal measures the colour cast of the background areas and subtracts this uniformly over the whole image. The original colour of the stars will be preserved - as long as the stars are themselves not over exposed. OK the brightest stars in your image will be overexposed but the majority will not.

Actually you are right. Preserving star colour is a skill that has to be learnt - it is usually best done in photoshop. In fact I'm currently writing my own PS plugin to manage star colour preservation

(Post Laureate)

07/04/09 08:45 PM

Re: rube goldberg M31

Well M31 is back , nice work.

(super member)

07/05/09 06:54 AM

Re: rube goldberg M31

Have to say thats a great shot with only just over 30 minutes of data, and at 30 seconds each.
Great attempt, can't wait to see what you can do with longer subs....

Regards, Neil.

(member)

07/05/09 11:27 AM

Re: rube goldberg M31

Quote:

And I'd have to pay my son to sit with me through an astrophotography session. So fine job to the both of you!

My son got me started on hooking up a digital camera (an XS in my case, a D70S in his) to my telescopes -- my interest has always been in the visual arena, not the photographic one. The last week has been our first serious attempt to make this digital astrophotography enterprise work, e.g., taking the time to perform a decent drift alignment, getting serious about focusing, etc.

So he's my digital mentor, and I doubt I could keep him away from the telescope if I tried!

Thanks for the words of encouragement.

(Carpal Tunnel)

07/05/09 07:30 PM

Re: rube goldberg M31

Rube would be proud! You got the job done!

(Vendor (DSLR-AstroMod))

07/08/09 02:03 AM

Re: rube goldberg M31

Nicely done Mish on an excellent 1st image!!, and welcome to the wacky wonderful and at times frustating world of DSLR astro imaging!

(scholastic sledgehammer)

07/08/09 02:17 AM

Re: rube goldberg M31

Nice image Mish,Keep up the good work

Bob

(member)

07/08/09 11:19 AM

Re: rube goldberg M31

Mish:

Personally, if I had something that good, I would see no reason to improve on it.

Very nice!

(sage)

07/08/09 11:46 AM

Re: rube goldberg M31

Very nice!
I figured you had the camera duct taped to the telescope with a water fed gravity assisted cable release.

(Carpal Tunnel)

07/08/09 09:04 PM

Re: rube goldberg M31

good start, better than my first effort!

(Carpal Tunnel)

07/09/09 12:53 AM

Re: rube goldberg M31

Quote:

good start, better than my first effort!

Very nice first image, my first stuff was laughable. And I have yet to nail the big galaxy.

(member)

07/09/09 06:51 PM

Re: rube goldberg M31

Quote:

I figured you had the camera duct taped to the telescope with a water fed gravity assisted cable release.

My first few times out with the Ultima-11 did involve a lot of duct tape, as I didn't have any counterweights and the fork mount really needs balancing due to that big primary mirror. So I filled a couple heavy bags with 16d nails and duct-taped them to the front of the scope.

And I do use a gravity-assist mechanism, but thankfully, there's no water involved. I have so much gear hanging on this overloaded mount that I adjust the counterweight on the bottom rail so that gravity is driving the Byers gearing, so all that thing has to do is govern the speed of the right ascension motion -- it doesn't actually have to move the telescope.

So far, it working out well. But it's been really windy for the last few nights, and I've got no cure for the wind's effect on my images. I wonder what Rube would do about that...

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