Another Elephant Trunk

Mike Lewis

Mike Lewis

Staff Member
So I have never come close to spending as much time on an object as I did on this one, both in the data collection AND in the processing. The ~25 hours of data collection were partially the result of how this was placed in the night sky, making it a great target to start imaging and then let run as I slept a few hours before dawn. The long processing was due to the fact that I had a certain look I wanted to get out of my narrowband palette, and it stubbornly refused to come. Eventually, after a number of hours fooling with the color mix I got something that at least is in the spirit of what I was hoping for. The processing had my trying out a number of techniques I had not used before - removing stars and mixing starless images from each filter, and then adding back in RGB stars from some very small stacks of RGB data I had taken along with the multiple hours of narrowband data. I utilized all 3 of my typical software packages too. Pixinsight did all the preprocessing and much of the post processing work, Photoshop was used extensively when experimenting, but ultimately was primarily used for the combination of the RGB stars to the starless NB data, plus a bunch of minor tweaks to the color mix, and Lightroom did the final sharpening, NR, and conversion to jpg files.

Narrowband processing at least for me remains a difficult process, but I did learn a bit on this journey. I am quite certain the processing hours exceeded the 25 hours of data collection by a noticeable margin, although I mercifully did not keep track of that :)

Comments and critiques welcome, and thanks for looking!

LRCC_sRGB_FW_ElephantTrunk_LRGB_PSCC.jpg


Collection Details

Light Frames:
Ha - 97 x 300 secs
SII - 103 x 300 secs
OIII - 88 x 300 secs
Red - 47 x 30 secs
Green - 47 x 30 secs
Blue - 46 x 30 secs

OTA: Stellarvue SVQ100 580mm f/5.8 refractor
Camera: ZWO ASI1600MM-cool, gain 200, Offset 50, Temp -20C
Mount: Software Bisque Paramount MyT
Guiding: Most unguided, but last data collect using Innovations Foresight ONAG for Guiding and focusing
Software: TheSkyX, SkyGuard ONAG software for some of the latter frames

Total 25 hrs, 10 mins


ML
 
JimFox

JimFox

Moderator
Staff member
This looks super cool Mike!

Though I know you had to work hard on the processing of this, it certainly paid off as I think the result of this is something for you to be proud of. This certainly stands up to the best of the Elephant Trunk images that I have seen so far in my short Astrophotography career. :)

One small question on your workflow. If all you did in LR is sharpen, NR and save to jpg, why didn't you just do it in Photoshop since you were already using it? There is nothing that LR does that Photoshop can't do.
 
Mike Lewis

Mike Lewis

Staff Member
JimFox said:
This looks super cool Mike!

Though I know you had to work hard on the processing of this, it certainly paid off as I think the result of this is something for you to be proud of. This certainly stands up to the best of the Elephant Trunk images that I have seen so far in my short Astrophotography career. :)

One small question on your workflow. If all you did in LR is sharpen, NR and save to jpg, why didn't you just do it in Photoshop since you were already using it? There is nothing that LR does that Photoshop can't do.
Click to expand...

Jim,

Thanks for the positive feedback! I think one always sees places that the results could be improved, but certainly after all the work I am pretty happy with this result!

The reason to use Lightroom is simply twofold - I am more familiar with it and so can make the adjustments needed more confidently there, and because Lightroom imports your images (essentially putting them into a database) I then have all the non-destructive edits, keywording and image location info in an easily looked up location where I can manage it in the future. You can probably accomplish a lot of the same think by using Bridge with Photoshop, but I like the way that is all baked into Lightroom in a native way.

ML
 
Mike Lewis

Mike Lewis

Staff Member
Ben Egbert said:
What strikes me here is how clean it looks, Very nice results.
Click to expand...
Ben,

Thanks for the nice comments! The results start to 'clean-up' as a result of stacking more frames. In addition to the extra signal that is integrated, the random portion of the noise contribution averages out as more frames are stacked. If one dithers (makes tiny little movements of the mount in between images) even the fixed pattern noise can then also be somewhat averaged out as well.

ML
 
Colorado CJ

Colorado CJ

Well-Known Member
Looks great to me, very "smooth" result!

Images like this make me want to break down and buy PixInsight. I just feel I might be missing something with just using Photoshop.

Awesome shot!
 
JimFox

JimFox

Moderator
Staff member
Mike Lewis said:
Jim,

Thanks for the positive feedback! I think one always sees places that the results could be improved, but certainly after all the work I am pretty happy with this result!

The reason to use Lightroom is simply twofold - I am more familiar with it and so can make the adjustments needed more confidently there, and because Lightroom imports your images (essentially putting them into a database) I then have all the non-destructive edits, keywording and image location info in an easily looked up location where I can manage it in the future. You can probably accomplish a lot of the same think by using Bridge with Photoshop, but I like the way that is all baked into Lightroom in a native way.

ML
Click to expand...
Gotcha, thanks for the explanation.
 
Mike Lewis

Mike Lewis

Staff Member
Colorado CJ said:
Looks great to me, very "smooth" result!

Images like this make me want to break down and buy PixInsight. I just feel I might be missing something with just using Photoshop.

Awesome shot!
Click to expand...

Andrew,

Thanks for the response. Your post-processing skills just using Photoshop are excellent - I wish I was as skilled with that program. That being said, I do think that PI really brings a lot to the table for this stuff, and it is really pretty cost effective considering all the constant updating they do to it. PI has a reputation for being hard to learn, but seeing how quickly you rose up the astrophotography ladder I feel confident in saying you would have no issues with it at all in a very short time. And in truth, using PI along with Photoshop (and also Lightroom as I did here) really gives you the best of everything because as you know, for many desired results, there are many different post processing ways to get there.

PI has no upgrade policy which also scares some folks away because when they do a major upgrade you have to buy the product again. However, in the 10+ years I have been using it, they have added lots of tools and scripts, and still have not called any updates a major upgrade, so I think they are pretty conservative on that. At this point my total cost averaged over the 10 years for the one time cost I have paid so far is about $26 - I wish everything I spent money on in this hobby was as smart a purchase as this was for me :)

ML
 
Nilo Photography

Nilo Photography

Well-Known Member
Mike Lewis said:
So I have never come close to spending as much time on an object as I did on this one, both in the data collection AND in the processing. The ~25 hours of data collection were partially the result of how this was placed in the night sky, making it a great target to start imaging and then let run as I slept a few hours before dawn. The long processing was due to the fact that I had a certain look I wanted to get out of my narrowband palette, and it stubbornly refused to come. Eventually, after a number of hours fooling with the color mix I got something that at least is in the spirit of what I was hoping for. The processing had my trying out a number of techniques I had not used before - removing stars and mixing starless images from each filter, and then adding back in RGB stars from some very small stacks of RGB data I had taken along with the multiple hours of narrowband data. I utilized all 3 of my typical software packages too. Pixinsight did all the preprocessing and much of the post processing work, Photoshop was used extensively when experimenting, but ultimately was primarily used for the combination of the RGB stars to the starless NB data, plus a bunch of minor tweaks to the color mix, and Lightroom did the final sharpening, NR, and conversion to jpg files.

Narrowband processing at least for me remains a difficult process, but I did learn a bit on this journey. I am quite certain the processing hours exceeded the 25 hours of data collection by a noticeable margin, although I mercifully did not keep track of that :)

Comments and critiques welcome, and thanks for looking!

View attachment 29435

Collection Details

Light Frames:
Ha - 97 x 300 secs
SII - 103 x 300 secs
OIII - 88 x 300 secs
Red - 47 x 30 secs
Green - 47 x 30 secs
Blue - 46 x 30 secs

OTA: Stellarvue SVQ100 580mm f/5.8 refractor
Camera: ZWO ASI1600MM-cool, gain 200, Offset 50, Temp -20C
Mount: Software Bisque Paramount MyT
Guiding: Most unguided, but last data collect using Innovations Foresight ONAG for Guiding and focusing
Software: TheSkyX, SkyGuard ONAG software for some of the latter frames

Total 25 hrs, 10 mins


ML
Click to expand...
Absolutely amazing shot!
 
Mike Lewis

Mike Lewis

Staff Member
Jim,

Well, of course, astro cameras do not have ISO settings per se. Many older CCD astro cameras have a fixed gain, while many newer CMOS cameras do have variable gain (so the same thing as ISO) but not specified that way. In the case of this image, all the subframes were shot at gain setting 200, which is just a number. Gain setting 139 on my astro camera equates to unity gain, and gain setting of 200 is about twice that. So if a setting of 139 means 1 count per detected photon, then gain setting of 200 means 2 counts per detected photon. If you know what ISO creates unity gain for your DSLR, then you could obviously double that ISO and have an equivalent gain. Of course, another point to be made here is that my current astro camera only has a 12 bit ADC, unlike many DSLRs which typically run at more like 14 bits. So there is a 4 fold increase in counts there. But the concepts are still the same I think...

Hope that helps,

ML
 
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