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1st and 2nd try Processing M31

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#1 Slice1969

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Posted 24 January 2020 - 10:11 PM

This is my 2nd ever astrophoto, so please be gentle.

 

I didn't spend too much time on the first one, but I have been working on the 2nd image off and on all day.  I have mostly been experimenting with Photoshop, which is also new to me.

 

This is 2.5 hours of integration time.  50 x 180s at ISO800.  I used all the subs on the 1st one, and the best 80% on the second. 

 

They are stacked with darks, flats, and bias frames.

 

Taken with a modded Canon T3i, and an 80mm triple APO with a flattener/reducer.

 

My biggest question is does the 2nd image look like it has been overprocessed?

 

All constructive criticism is welcome.  Thanks

 

 

My first try:

get.jpg?insecure

 

The Second:

get.jpg?insecure

 

 

 

 


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#2 Alen K

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Posted 24 January 2020 - 10:18 PM

Only your second astrophoto? Impressive. The second one is much better. About the only thing I can critique for that one is that the black level may be a little low. 


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#3 Slice1969

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Posted 24 January 2020 - 10:58 PM

Thanks.  Getting the black level right has been a challenge so far. 



#4 Cfreerksen

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Posted 24 January 2020 - 11:01 PM

I would second the first critique. Impressive. Don't crush the blacks. Make it a very dark grey. You may be leaving some nice details in that black. Try and give it a touch more blue to bring out some of the stars.

 

Nice job.

 

Chris



#5 lambermo

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Posted 25 January 2020 - 09:33 AM

The galaxy contrast, dynamic range and the colors in it have been much improved. The stars in the second image are not, those are worse than in the first image.

Both are very impressive for your second image !



#6 RedLionNJ

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Posted 25 January 2020 - 12:22 PM

Nice results.

 

As mentioned above, there's quite a bit of black-clipping present. Don't be so harsh in that direction.

 

The colors could pop a little more (without being scary vivid). You could do a Lab transformation and apply an S-curve to see the effect.  Experiment a bit with this.  The colors of the unsaturated stars could stand out a bit more, too.

 

The contrast of the dust lanes could be a little more severe, but not so much as to look phony.

 

Great 2nd attempt. You can play with this stuff for days or weeks.



#7 Slice1969

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Posted 25 January 2020 - 12:48 PM

Thanks for all the feedback.  There is certainly a lot to work with there.

 

I will spend some more time with it today, and see what I can do.

 

It's tricky when you start experimenting... you get an effect you like, but then mess it up with something else, tinker some more.  After an hour or two, you realize it looks worse than what you started with! 

 

The post process has definitely got the steepest learning curve for me.  



#8 Alen K

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Posted 25 January 2020 - 01:02 PM

The galaxy contrast, dynamic range and the colors in it have been much improved. The stars in the second image are not, those are worse than in the first image.

I think that is just a result of more severe black clipping. The natural "tails" of the Gaussian profiles are more severely clipped. Note that M31 also extends outward more in the first image and there is some red glow (amp glow?) On the leftmost third of the bottom edge and along the left side itself. I would bet that lowering the black level was an attempt to clip that off. The histograms of both images show clipping but the second one is worse. Besides the "amp glow" and the black clipping the worst problem with the first image is saturation of M31's core along with the red ring around it (looks like red clipped first). In both images there is a general lack of star colors, which is another indication of saturation but the first image is worse in that regard. I'm not sure if the 3-minute exposures were a tad too long but I think some of the star colors could be recovered in processing.

 

However, none of this critique is intended to take away from what is a fine accomplishment! 


Edited by Alen K, 25 January 2020 - 08:14 PM.


#9 Simon D.

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Posted 25 January 2020 - 06:37 PM

Looks great.  Not much to add other than possibly a cooler white balance would make the core less yellow and add a nice blue fringe around the edge of the galaxy.  Excellent work!



#10 Slice1969

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Posted 25 January 2020 - 07:59 PM

I'm still working on M31.  I haven't been able to get it right to my liking yet, but all of the advice has helped greatly.  In the meantime, I gave my wife the choice of 3 objects for my session last night.  She picked the Rosette Nebula.

 

I got my black level better on this one, I think.

 

get.jpg?insecure




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