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nmoushon

8hrs - M31 & M42

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Here are my winter projects so far. It's been a very cloudy winter here near Chicago this year and very busy one too so haven't been out too much. I used ED80+450D on Sirius EQ-G for both images. I just got a QHY5-II for guiding but didnt have it for these two targets so these are both unguided. For both targets I used primarily 120sec subs with a small 15/30 sec subs for the core and the trapezium area for a total amount of 8 hours of data for both targets. I used darks, flats and bias as well.

I'm still struggling to get layer masking down to control the trap area of M42 and especially the core of M31. If anyone knows any good tutorials or can give some pointers that would be awesome. For both images the post processing was JUST with levels and curves and 1 small high pass filter. Thats it.

One reason I went for 8 hrs of data was because of a thread a couple of months ago that started the F/ratio vs total time vs depth of the image. So I decided to find out what exactly I would get in 8 hrs of data instead of the normal 2-3 hrs people usually shoot for both of these bright objects. They both have fainter detail that can be brought out as well. After 8hrs of 120sec subs and my decent attempt at processing I was not able to bring out any of the fainter detail or halo of M31 and was JUST bairly bringing out the fainter part of the nebula surrounding M42 but the data is not strong enough to really even look good to be brought out. You can just see it coming out in the bottom right corner of the uncropped M42. So my concluded, what I originally thought, that yes you can increase the depth of an image with short subs and large amounts of subs but you would really need a lot of subs. I would guess I would need another 8hr on M42 to be able to get the fainter nebula to even look decent. So as I originally thought that you either need longer single subs or a faster f/ratio to be able to get greater depth in your data. Without driving you insane that is. The one thing that 8hr did do was REALLY cut down on noise. Especially with a noisy 450D it really improves your image. So if you have the time and patients to get the extra hours in I think its well worth it.

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Edited by nmoushon
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Fantastic images, especially m31 , well done !

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Absolutely excellent !!!!!!

I know there is a neutral density filter that can be shaped in Photoshop but I have never used it myself I know there were also preset shapes too, I only use the drop down type to darken the sky, but for sure there is a tool that you could darken the Trapezium area with.

Alan.

Edited by alan potts

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Nice shots. Nice to see what you can get unguided (my current mount has no guide port, so there is hope :)). I hope to point my EOS 450D at the sky with the APM 80mm some time, but I do not think I have had 8 hours of clear skies in total this winter.

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Thanks for the suggestion Alan I'll have to look into that and give it a try.

Michael I did not take these in one night or even two. It took 4-5 nights for each image and they where spread out over 3 months! I've had horrible skies this winter as well. So its defiinately duable if you have the patients. You can get great images with half the time I spent. I honestly did not use as much darks as I usually do. Only have about 3hrs worth of darks data. I usually aim for at least half the total exposure time(that's just my personal preferance). So you can bring down the noise with doing more darks which you can do when it clouds over and not have to waiste the clear skies.

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Very nice images. I agree that its really worth picking one or two projects a season and taking the time to capture loads of data. The results speak for themselves. Its all to easy to grab as many targets as you can but not do them justice due to a lack of data. Depends what result you're aiming for i guess, but i'm with you.

Keep up the good work!

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Great set of images nicely done if you want some help on layering the core check out my blog and tube channel were I posted a set of processing tutorials ;)

Sent from my Scroll Plus using Tapatalk 2

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Very nice indeed :)

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http://www.astropix.com/HTML/J_DIGIT/LAYMASK.HTM That's a great tutorial on how to layer mask, and it uses M42 as the example. It's the way I do it and gives a nice result, I'd say. It will do wonders for your M42. Don't over stretch your short subs.

Colour balance is great in Andromeda. In M42 you have too much green. Look at the histograms for the three colours. Clip the black points to get the top left of the peak aligned in all channels. If green still dominates try downloading the free/donation Hasta La Vista Green on the Deep Sky Colors website or try SCNR Green if you have Pixinsight.

Olly.

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Great set of images nicely done if you want some help on layering the core check out my blog and tube channel were I posted a set of processing tutorials ;)

Sent from my Scroll Plus using Tapatalk 2

I really love this quote.  I will check out the photoshop instructions.  Thanks this is a great site

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need

Here are my winter projects so far. It's been a very cloudy winter here near Chicago this year and very busy one too so haven't been out too much. I used ED80+450D on Sirius EQ-G for both images. I just got a QHY5-II for guiding but didnt have it for these two targets so these are both unguided. For both targets I used primarily 120sec subs with a small 15/30 sec subs for the core and the trapezium area for a total amount of 8 hours of data for both targets. I used darks, flats and bias as well.

I'm still struggling to get layer masking down to control the trap area of M42 and especially the core of M31. If anyone knows any good tutorials or can give some pointers that would be awesome. For both images the post processing was JUST with levels and curves and 1 small high pass filter. Thats it.

One reason I went for 8 hrs of data was because of a thread a couple of months ago that started the F/ratio vs total time vs depth of the image. So I decided to find out what exactly I would get in 8 hrs of data instead of the normal 2-3 hrs people usually shoot for both of these bright objects. They both have fainter detail that can be brought out as well. After 8hrs of 120sec subs and my decent attempt at processing I was not able to bring out any of the fainter detail or halo of M31 and was JUST bairly bringing out the fainter part of the nebula surrounding M42 but the data is not strong enough to really even look good to be brought out. You can just see it coming out in the bottom right corner of the uncropped M42. So my concluded, what I originally thought, that yes you can increase the depth of an image with short subs and large amounts of subs but you would really need a lot of subs. I would guess I would need another 8hr on M42 to be able to get the fainter nebula to even look decent. So as I originally thought that you either need longer single subs or a faster f/ratio to be able to get greater depth in your data. Without driving you insane that is. The one thing that 8hr did do was REALLY cut down on noise. Especially with a noisy 450D it really improves your image. So if you have the time and patients to get the extra hours in I think its well worth it.

Hi,

Nice captures, just follow Olly's advice for removing the green cast. As for the myth of 60 X 2 minutes exposure = 20 X 6 minutes exposure, as  you have found out this is not true. You need the longer exposures to bring out the faint details subject to the seeing conditions and the level of LP for your site, there is the law of deminishing returns after all. The larger the number of the subs the smoother the final stacked image but that does not mean  extra detail. A DSLR will always require a much larger number of frames to overcome the build up of noise compared to a cooled CCD plus the mandetory large number of the dark frames.

Regards,

A.G

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I enjoyed looking at your pics.  I only hope to obtain results any where near to yours within the next few months.

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