M51, The Whirlpool Galaxy, In LRGB plus Hα

[Mike Lewis]

I am enjoying going back to some of my previously imaged galaxies and getting a much closer and more detailed view using this longer focal length telescope.

This iconic target is one of the most mesmerizing objects in the night sky. First discovered by Charles Messier in 1773, M51 contains 2 interacting galaxies, the larger NGC 5194 face on spiral, and the smaller NGC 5195 galaxy (the yellow object to the right of the spiral in this image). These objects are bright enough to be detected with binoculars under dark skies, and reside approximately 31 million light years distant in the Canes Venatici constellation.

This was imaged in LRGB filters with additional Hα data added in to accentuate the reddish pink star forming regions. I have a rendition shot with my 580mm refractor and a much shorter duration which was my only previous image of this object that I am including for comparison. As always, comments and critiques are welcome, and thanks for looking!

Previously captured version (only 48 mins total integration):

Capture Details (For Larger Version)

Software:
PHD2 Guiding Software
NINA Astroimaging Software
Pixinsight Commercial Version 1.8
Software Bisque TheSkyX
Lightroom CC
Photoshop CC

Light Frames:
Luminance: 27 x 180 (1 hr 21 mins)
Red: 32 x 300 secs (2 hrs 40 mins)
Red: 32 x 30 secs (16 mins)
Green: 32 x 300 secs (2 hrs 40 mins)
Green: 32 x 30secs (16 mins)
Blue: 30 x 300 secs (2 hrs 30 mins)
Blue: 32 x 30 secs (16 mins)
Hα: 37 x 420 secs (4 hrs 19 mins)

14 hrs 18 mins total

Dark Frames:
10 x 30 secs, RGB (5 mins)
10 x 180 secs, RGB (30 mins)
10 x 300 secs, RGB (50 mins)

Bias Frames:
60

Flat Frames:
10 each filter

 

[JimFox]

Hey Mike,

M51 is one of the big ones we all image. It's up there with Rosette and Orion nebulas in terms of popularity. And you nailed it. The difference between the two images is startling, even though it should be expected, it's still amazing.

 

[Mike Lewis]

tweaked the black level on this one, I think it looks a little better.

And funny story around that. I was not only wanting to reduce the black level a bit, but i thought I saw a red cast to the image on one side too. I figured reducing the black level would help with that as well. Once I had adjusted it and exported the result, lo and behold if the reddish cast didn't almost seem more pronounced. Well long story short, I finally realized it was the bright orange T-shirt I was wearing, reflecting off the monitor screen, which became even more obvious once the background was darker. I could have chased that problem for QUITE some time, and really messed up the image in the process. Probably should wear black when editing photos, especially astro images apparently

Here is the new edit, let me know if you like it better. I think it accentuates the faint details a little better, while still preserving most of them.

ML

 

[JimFox]

Ha ha..... Now that's funny with your orange T-shirt. I wouldn't have even thought of that. Fortunately I typically where more gray and dull colors, but I hope I haven't had a similar issue and just didn't know it.

I definitely like the edit better. I think that would make for a great finished image.

One comment or thought now that I have gotten done running the grandkids around and can really look at this. The stars. I know you are shooting them in RGB and you image less for them so that they don't blow out. Now, maybe it's because I am so used to my stars being blown out, and so it might just be me. But it almost looks a bit odd with all of the stars being different colors. Now I know they are really different colors. But when I look up into the night sky, I don't see colored stars, I see bright white stars. So maybe that's why my blown out stars don't bother me.

And I am not saying these stars you have are bad, they actually are probably perfect. But I am speaking as more of a newbie where I am wondering if you wouldn't have wanted just some stars being white? Again, I had never thought about that before and I have seen lot's of processed images similar to yours, but it's just something that popped into my mind right now.

 

[Mike Lewis]

Ha ha..... Now that's funny with your orange T-shirt. I wouldn't have even thought of that. Fortunately I typically where more gray and dull colors, but I hope I haven't had a similar issue and just didn't know it.

I definitely like the edit better. I think that would make for a great finished image.

One comment or thought now that I have gotten done running the grandkids around and can really look at this. The stars. I know you are shooting them in RGB and you image less for them so that they don't blow out. Now, maybe it's because I am so used to my stars being blown out, and so it might just be me. But it almost looks a bit odd with all of the stars being different colors. Now I know they are really different colors. But when I look up into the night sky, I don't see colored stars, I see bright white stars. So maybe that's why my blown out stars don't bother me.

And I am not saying these stars you have are bad, they actually are probably perfect. But I am speaking as more of a newbie where I am wondering if you wouldn't have wanted just some stars being white? Again, I had never thought about that before and I have seen lot's of processed images similar to yours, but it's just something that popped into my mind right now.

Jim,

Thanks for the feedback. That is a good observation. I think stars like this is a matter of taste, pretty much like the different narrowband mixes are. Once you go beyond a very few very bright targets, none of this stuff is naked eye visible anyway, so it gets artistic from there. I am going for bringing out the color in the stars so I guess that is what I am getting.

But, all that having been said, I actually agree with you and feel that the stars as included here are not quite what I would like... I do think a couple of brighter white stars along with just a few more stars in general would be welcome and perhaps give things a more natural look. I am taking separate data for the stars as I do find that using the existing stars, even if I remove them and replace them is giving me some issues. So then these stars collected with less integration are what I am using instead. Even with less integration though I find that stretching them too much brings up the galaxy (even using small stacks of 30 second subs) and then getting that to not interfere with the starless galaxy colors that I have already worked on and gotten to my liking is a bit complicated. But on top of that, an even bigger potential problem is that I see some somewhat strange non-uniform colors on parts of some of the stars, and that gets to be more visible when bringing the star brightness up too far as well. I am not sure what that is, although I will say that I also see that with my friend's data captured with his larger EdgeHD 11" scope and a OSC camera, so maybe something in the scope or perhaps some kind of atmospheric dispersion effect?

But in point of fact, I do agree that the stars could have a better mix of colored and white, and actually be a bit larger too (a seemingly strange complaint) to make things look maybe a little less processed as far as the stars go. I may go back with this image and just try to play with that some more to see what I might get. Worth some more time to tinker with. So far it is the stars that are the only thing I am not quite satisfied with when imaging with this new setup.

 

[JimFox]

Jim,

Thanks for the feedback. That is a good observation. I think stars like this is a matter of taste, pretty much like the different narrowband mixes are. Once you go beyond a very few very bright targets, none of this stuff is naked eye visible anyway, so it gets artistic from there. I am going for bringing out the color in the stars so I guess that is what I am getting.

But, all that having been said, I actually agree with you and feel that the stars as included here are not quite what I would like... I do think a couple of brighter white stars along with just a few more stars in general would be welcome and perhaps give things a more natural look. I am taking separate data for the stars as I do find that using the existing stars, even if I remove them and replace them is giving me some issues. So then these stars collected with less integration are what I am using instead. Even with less integration though I find that stretching them too much brings up the galaxy (even using small stacks of 30 second subs) and then getting that to not interfere with the starless galaxy colors that I have already worked on and gotten to my liking is a bit complicated. But on top of that, an even bigger potential problem is that I see some somewhat strange non-uniform colors on parts of some of the stars, and that gets to be more visible when bringing the star brightness up too far as well. I am not sure what that is, although I will say that I also see that with my friend's data captured with his larger EdgeHD 11" scope and a OSC camera, so maybe something in the scope or perhaps some kind of atmospheric dispersion effect?

But in point of fact, I do agree that the stars could have a better mix of colored and white, and actually be a bit larger too (a seemingly strange complaint) to make things look maybe a little less processed as far as the stars go. I may go back with this image and just try to play with that some more to see what I might get. Worth some more time to tinker with. So far it is the stars that are the only thing I am not quite satisfied with when imaging with this new setup.

I totally agree with you that stars, and how many, or how bright or dim, or none at all comes down to artistic taste. That's why I was being not hesitant, but careful in my wording that there wasn't necessarily anything wrong with your stars, I had just observed they were a bit dim and all were colored. I appreciate you taking my comments as just a conversation and thinking back and forth as we all learn, and especially as I learn more being pretty new to Astro.

I don't know if you have looked at any of Lukomatico's video's on YouTube, but he has some really awesome stuff. Quite a bit of it is in regards to OSC cameras, which you might find helpful as you step your toes back into that realm this summer. But in terms of stars, he has an awesome Star routine that plays off of StarXterminator. So he has a set of 3 routines for placing stars back in. It's so painless to do. I am not sure which video it was, but it was within the last year.

 

[Mike Lewis]

So edited with Jim's comments in mind. As expected I had to work a little to keep the more aggressively stretched star layer from affecting the galaxy and the tidal tails that I had worked on without the stars present. Probably would have not been an issue if I started with these stars, but going back into that part of the process with this new star layer and the old image to try to match made it a bit tweaky. Definitely produces a different look. I think I like it, but for those not already sick of this progression of images who want to weigh in on this latest edit I would be interested to hear your take.

I am going to refrain from updating the file on my website and on my Astrobin site for a few days to think about which I like and to collect feedback from others. A good exercise though so very glad for the suggestion regardless of which I decide I like the best.

ML

 

[JimFox]

It looks better Mike, but could be pushed a bit more I think. Though maybe sit on it for a day to see.

You should remove the stars from the more aggressively pushed image, that way you aren't dealing with an overly stretched galaxy, and then just add those stars into your existing properly stretched image.

 

[Mike Lewis]

Jim,

That's what I did, but the extra stretch of the star layer can raise the background level and also bring up non-star portions of the galaxy even though the galaxy was removed from the stars. This then can introduce subtle changes to the galaxy luminance level and add some artifacts. Also in this case I had introduced some color palette tweaks and level tweaks after the stars were introduced in the original image, so getting those back in quickly meant some additional interactions with the brighter star layer. Again, if the star layer had been processed appropriately the first time around and all of the color and level tweaks had been done to the starless image before the stars were added all of this would have been easier. But in this case I only went and looked critically at the colors of other awarded Astrobin versions of M51 after I had combined everything and at that point decided my version was a little bit too green. Not the best workflow and not my usual approach.

As far as this result goes, I think pushing the stars beyond this level not only starts to lose too much many of the colored stars but then enters into the range where the stars start to overpower the galaxy and one needs to mess with star reduction so I feel like it is this version or the previous one for me, but of course it is good to have feedback. Will be interesting to see what others on FocalWorld might think, and also to hear the consensus tomorrow on my astrophotography Zoom meeeting with my fellow astrophotographers.

Thanks so much for the feedback it is most appreciated!

 

[JimFox]

Jim,

That's what I did, but the extra stretch of the star layer can raise the background level and also bring up non-star portions of the galaxy even though the galaxy was removed from the stars. This then can introduce subtle changes to the galaxy luminance level and add some artifacts. Also in this case I had introduced some color palette tweaks and level tweaks after the stars were introduced in the original image, so getting those back in quickly meant some additional interactions with the brighter star layer. Again, if the star layer had been processed appropriately the first time around and all of the color and level tweaks had been done to the starless image before the stars were added all of this would have been easier. But in this case I only went and looked critically at the colors of other awarded Astrobin versions of M51 after I had combined everything and at that point decided my version was a little bit too green. Not the best workflow and not my usual approach.

As far as this result goes, I think pushing the stars beyond this level not only starts to lose too much many of the colored stars but then enters into the range where the stars start to overpower the galaxy and one needs to mess with star reduction so I feel like it is this version or the previous one for me, but of course it is good to have feedback. Will be interesting to see what others on FocalWorld might think, and also to hear the consensus tomorrow on my astrophotography Zoom meeeting with my fellow astrophotographers.

Thanks so much for the feedback it is most appreciated!

Thanks for the explanation. I haven't seen that so far in mine, but of course my stars are almost always plenty bright since at this point I am not shooting separate for the stars, though I have thought about doing that a couple of times when using the L-Enhance filter.

 

[Comet Hunter]

It never ceases to amaze me how we can, with consumer grade equipment, image the marvels of the universe from our back yard (or driveway in my case)

And this is a excellent example of that very thing. Such a fun hobby

Nicely done.

 

[Mike Lewis]

It never ceases to amaze me how we can, with consumer grade equipment, image the marvels of the universe from our back yard (or driveway in my case)

And this is a excellent example of that very thing. Such a fun hobby

Nicely done.

Could not agree more. It is really incredible to compare amateur results of today to the BEST results using the largest telescopes on planet earth, back when film was the only medium for capture. The improvements once digital sensors entered the scene are mid blowing, and now having all that tech available to amateurs it just makes the hobby so rewarding. Thanks for your kind and insightful comments.

ML

 

[Dan Moorehead]

Wonderful