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Astrophotography and Sketching >> Beginning and Intermediate Imaging

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Madratter
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Reged: 01/14/13

Re: Detail in the Soul Nebula new [Re: Madratter]
      #6258635 - 12/17/13 05:39 PM

I should add that I definitely could have used more aggressive noise reduction but then you have the problem with things looking artificial and plastic like.

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jbalsam
sage
*****

Reged: 07/06/12

Loc: Darnestown, MD
Re: Detail in the Soul Nebula new [Re: Madratter]
      #6258658 - 12/17/13 05:53 PM

Agreed, Madratter - too much denoising makes things look far worse.

I'm curious about why you are limited to 5min exposures with a guide scope. What problems are you seeing at longer exposures?


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Madratter
Post Laureate


Reged: 01/14/13

Re: Detail in the Soul Nebula new [Re: jbalsam]
      #6258728 - 12/17/13 06:32 PM

I have enough flexure in the system that stars go noticeably out of round in reasonable seeing after that amount of time. I actually could go longer with my C8 despite mirror flop. My guess is that the flexure in the AT8RC is from the way the focuser is mounted to the primary. Just .2 arc-second of movement a minute leads to an error of 2 arc-seconds which is easily noticeable after 10 minutes. I hate eggs. Hence why I will probably be getting a OAG soon.

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jbalsam
sage
*****

Reged: 07/06/12

Loc: Darnestown, MD
Re: Detail in the Soul Nebula new [Re: Madratter]
      #6258744 - 12/17/13 06:40 PM

Weird. It does look like most people on AstroBin who use the AT8RC use an OAG. I see a few examples of people taking 10min images with guidescopes, but they are few and far between.

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terry59
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Reged: 07/18/11

Loc: Colorado, USA
Re: Detail in the Soul Nebula new [Re: Madratter]
      #6258759 - 12/17/13 06:47 PM

Quote:

My guess is that the ideal exposure where read noise gets overwhelmed is probably at least ten and more probably twenty plus minutes. Unfortunately, until I get OAG going, I need to live with five minute exposures. That is fine for LRGB where it does hit or come close to ideal exposure times.

My telescope is running at roughly f/5.8.




Hmmm....I'm shooting 10 and 15 min subs now in NB.I should probably try 30 but I'd hate to lose any of those!


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DrDispatch
sage
*****

Reged: 10/26/12

Loc: Spf, Mo
Re: Detail in the Soul Nebula new [Re: terry59]
      #6258799 - 12/17/13 07:08 PM

i can go 20 min most times, almost every time i go 30 min something happens.
also I do not see much gain on my system above 15-20 min.


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SergeC
scholastic sledgehammer
*****

Reged: 03/23/12

Loc: Gainesville, FL
Re: Detail in the Soul Nebula new [Re: jbalsam]
      #6258811 - 12/17/13 07:16 PM

Quote:

Agreed, Madratter - too much denoising makes things look far worse.

I'm curious about why you are limited to 5min exposures with a guide scope. What problems are you seeing at longer exposures?



Me, too. I'm over the half-max load on my CGEM, and can get 15min at 800mm focal length, guiding with a Mag-Mini, and not have to throw away any subs (last night I shot 4 hours worth at 15min each, kept 'em all).


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jbalsam
sage
*****

Reged: 07/06/12

Loc: Darnestown, MD
Re: Detail in the Soul Nebula new [Re: SergeC]
      #6258830 - 12/17/13 07:28 PM

Well... Madratter is using a heavier camera than you are, Serge. Maybe that's causing additional flexure in the focuser/mirror cell connection?

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Madratter
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Reged: 01/14/13

Re: Detail in the Soul Nebula new [Re: jbalsam]
      #6258895 - 12/17/13 08:19 PM

Serge is shooting the AT8IN, not the AT8RC so he doesn't have the same problem in terms of the mounting of the mirror cell. And the heaviness of the camera is probably a factor.

Edited by Madratter (12/17/13 08:20 PM)


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SergeC
scholastic sledgehammer
*****

Reged: 03/23/12

Loc: Gainesville, FL
Re: Detail in the Soul Nebula new [Re: Madratter]
      #6259064 - 12/17/13 09:56 PM

OK, that makes sense.

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Madratter
Post Laureate


Reged: 01/14/13

Re: Detail in the Soul Nebula new [Re: rigel123]
      #6259079 - 12/17/13 10:07 PM

Quote:

That's close to the same FOV I used for my image of this one, great job!




Thanks! I went looking for yours. Very nice.


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Madratter
Post Laureate


Reged: 01/14/13

Re: Detail in the Soul Nebula new [Re: Madratter]
      #6261032 - 12/18/13 10:31 PM Attachment (3 downloads)

Well we are dancing in the moonlight tonight gathering some more data for this. Actually, I already have all the subs and have switched to another target. I got some color data but more importantly, I got some 10m subs that look pretty good. As far as ideal exposure time, SGP was telling me 15.7 minutes for Ha at 2x2.

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hytham
scholastic sledgehammer
*****

Reged: 12/25/12

Loc: Canadian in the US
Re: Detail in the Soul Nebula new [Re: Madratter]
      #6261185 - 12/19/13 12:59 AM

What State do you live in?

I haven't had a clear sky in weeks.


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Madratter
Post Laureate


Reged: 01/14/13

Re: Detail in the Soul Nebula new [Re: hytham]
      #6261245 - 12/19/13 02:39 AM

Maryland. I don't have the best skies in the world, but far from the worst.

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terry59
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Reged: 07/18/11

Loc: Colorado, USA
Re: Detail in the Soul Nebula new [Re: Madratter]
      #6261361 - 12/19/13 06:55 AM

Quote:

Maryland. I don't have the best skies in the world, but far from the worst.




I think you live in an alternate universe!


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jbalsam
sage
*****

Reged: 07/06/12

Loc: Darnestown, MD
Re: Detail in the Soul Nebula new [Re: terry59]
      #6262025 - 12/19/13 02:18 PM

I'm in MD, too (Montgomery County). Isn't it great how the clear nights always seem to land near the full moon?

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Madratter
Post Laureate


Reged: 01/14/13

Re: Detail in the Soul Nebula new [Re: jbalsam]
      #6262035 - 12/19/13 02:23 PM

It does seem to work out that way.

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Madratter
Post Laureate


Reged: 01/14/13

Re: Detail in the Soul Nebula new [Re: Madratter]
      #6262504 - 12/19/13 07:19 PM Attachment (3 downloads)

As mentioned, I got some more data last night: RGB of 30, 30, and 35 minutes, plus another 110 minutes of Ha. 90 of that was with 10 minute exposures, which really helped. Total integration time is now 380 minutes (6 hours 20 minutes).

The color version can be found here:



And here is a crop of the processed HA data.

Edited by Madratter (12/19/13 07:22 PM)


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terry59
Post Laureate
*****

Reged: 07/18/11

Loc: Colorado, USA
Re: Detail in the Soul Nebula new [Re: Madratter]
      #6262539 - 12/19/13 07:41 PM

The additional Ha smoothed the faint stuff and the blend went very well.

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CounterWeight
Postmaster
*****

Reged: 10/05/08

Loc: Palo alto, CA.
Re: Detail in the Soul Nebula new [Re: terry59]
      #6262573 - 12/19/13 08:03 PM

Madratter that is nice stuff, very nice! I'd love to see a mosaic at this resolution projected on a wall screen .

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