M31 Andromeda

[Celestron]

This is another stack of images of M31 . Lacks lot's detail . 35x1-mins with the 70-200mm f/4L USM & XSi piggyback my 8" SCT . Can't seem to get much out of this but Cs'&Cs' welcome .

[TC_Fenua]

Hmm , which ISO did you use , 100 ? I would try 500 or 800 max . To bad , because you got a steady guiding/tracking.

[jmx]

35 minutes at f/4 should have been plenty for detail. Can you post a 16bit tiff somewhere?

Here's a shot I took of 50 x 1 minute at f/5 for comparison (at 750mm rather than 200).
http://jmx.ls1howto.com/pics/m31_1280.jpg

It may just come down to processing?

[Adrena1in]

Lacks lot's detail.

That is seriously lacking if you were using 1-minute subs at f/4. I guess that asking you to check the ISO is like asking a Granny to suck eggs, but it's the only thinkg I can think of too. My only half-successful shot of M31 (http://img501.imageshack.us/img501/2601/andromedajpgspp2td6.jpg) was a stack of one 1-minute sub and six 2-minute ones, at 400mm and f/5, ISO 800 or 1600, can't remember. If they'd all been 1-minute I don't think there would have been a lot of difference.

EDIT: Downloading your image and using my limited editing tools here at work I can see there is more data in your image than is shown above. I expect someone else here can extract a bit more from it.

[Celestron]

I'll try to post a TIF on my website if i have room but it will be late tonight . Not able to at the moment . this has a mixture or 800 & 1600 ISO . Mostly 1600 ISO .

[VIGER]

35x1-mins ????

How did you stack these?

[Celestron]

????

How did you stack these?


DeepSkyStacker (http://deepskystacker.free.fr/english/index.html)

[VIGER]

Stange. Can we see a single frame?

[Celestron]

Stange. Can we see a single frame?


I'll try tonight . I'm at work now and on a different computer .

[Celestron]

Ok a quik one at lunch . I went back and counted all my stacked images and sorry but i was wrong on the timing for a few :( . Turns out i had 2x30-sec@1600 ISO , 1x120-sec@1600 ISO , 11x30-sec@800 ISO . But it totals 31.5-mins so short a few mins . Sorry ! Below is 1 @ 60 @ 1600 ISO , and 1 @ 120 @ 1600 ISO . Had to reduce them to post them , sorry ! My website won't let me upload a TIF format so don't know how i can do that at the moment.

[VIGER]

To me it's a staking issue. I can see more data in that frame thatn the stack final.

That using a cheap monitor from work ....

[TC_Fenua]

I concur , it has to be a stacking issue. Did you ever tried to use Iris software ? Kinda hard to understand how it works at first but once you get used to it , it's a great tool.

[Celestron]

I've started all over again but haven't got to stacking part yet . I keep running out of time :( .

[Nighthound]

This is exactly what I would expect from 31 minutes of data collected at f/4 under moderately light polluted skies (assuming you shot from home).

Very good work Ron. Your color balance is great, histogram is nice with black point not clipped. As you know I shoot at f/4 with both scopes(haven't tried the 500L-f/4 yet) and I didn't see a large jump in detail or brightness in the outer regions until I hit the two hour mark on M31. In my experience 3 hours, like with many DSOs is when things really start to happen with a DSLR.

I don't use DSS so I can't make any suggestions in that part of the processing.

Your single biggest drawback here is the length of your sub exposures which I realize are limited by various factors like skies, and tracking limits. My subs are between 4 and 5 minutes each under mag 4.5 to 6 skies. That seems to be the sweet spot for the 20D and my mount. There are nights when I can go longer when autoguiding but I don't see a drastic beneficial gain in data and start losing usable subs to excess noise and light pollution/sky glow. My point is for you to gather the majority of the preferred 2-3 hours in short subs simply won't amount to that resulting from longer subs. You need to grab the faintest stuff in every frame to see it in the end, and with M31 there's a lot of faint stuff, as you know. Of course, the darkness of the skies you image under makes a big impact on what I just stated. Much more usable data can be gathered in a minute when LP isn't eating up the faint stuff.

jmx did an awesome job with 50 minutes of data using 1 minute subs (great work jmx). His processing skills really dug out the most from his files. Certainly your image has more that can be coaxed out too, stretching carefully in PS using curves.

With all that aside, as I always say: Get the most you can with what you have and keep it fun.

I'm envious that you've been able to set up and enjoy the hobby. I've been shut out for 10 months due to bad skies on imaging weekends. I hope when I do get out that I can still remember how to polar align.

Great work buddy, keep 'em coming.

[VIGER]

http://i106.photobucket.com/albums/m271/MLaframboise/IMG_3085_B.jpg

This is what I get from it using your one frame. I rest my case. I did not even used Photoshop if I did I could of probably get more.

:p :eek:

[VIGER]

http://photography-on-the.net/forum/showthread.php?t=763083

Have you seen this tread ?

Cheers bud.

[Celestron]

http://photography-on-the.net/forum/showthread.php?t=763083

Have you seen this tread ?

Cheers bud.

Forgot that one . Have to re-read it when time given !