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Would love any comments and or critiques of my First light with the Rokinon 135mm paired with my asi 294mm at 2.3um 1x1 bin with eaf focusing, all riding in a celestron avx mount. https://www.astrobin.com/52x6em/C/ |
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Ok let honesty start. Actually, with a pretty darn good looking overall image! I thought I gave my thoughts in bullets, easier for me 😊. What I like: 1. I think the overall color assignment is well chosen, you dared to leave some green in here, and personally I think it is a lovely choice. I actually liked this image when I saw it right away 😊. 2. The inclusion of Heart and Soul in one image is a great choice. What I do not like: 1. I would get rid of the upper and lower parts of the image, they really do not add a lot to the image and distract from the main targets. 2. Too many stars. I would try to reduce them so that they do not distract from the nebula. This is one of the more difficult processes to achieve. Star Reduction is usually not good enough, I would try to get a starless image and then integrate a lower stretched star image into it. 3. For me there is still too much noise in the image, especially outside of the 2 nebulas. So I would either increase the integration time (which is for noise reduction and not to get more details!) or try to apply some noise reduction routines. 4. Not enough contrast. The darker areas did not come out as well as they should be. Maybe a bit too harsh of a stretch. In general this one is hard to judge for me since I do not have any experience with the Rokinon, and from other images I can see that the results of this camera are not that easy to process or that the scope has just some limits. One should not forget, just 135mm. With that I am still amazed how well it is performing. As a (previous) submitter I probably would not have marked this one for further recognition, but it would have been close. Ok, let me know what you think. Was I too hard, or wrong? Open discussions is the theme of this forum. Uwe P.S.: if you would have cropped a bit more your coma problems at the edges (which almost everybody has ) would not be visible 😊. And yes please: never not use flats, maybe most important addition of all. |
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Uwe Thank you for your gracious words!!! I have always been grateful for the astrophotography community's help to improve my work over the past 2.5 years. SHO color palette images are very touchy for my Left Brain way of thinking. I am just not that artistic and finding a balance is always difficult. The green battle is one a I attempt to fine tune for each image. I like to leave in more green then the majority of the community in order to show more gas delineation, but it is always hard to get correct. I too live through bullet points whether charting at work, public speaking notes, or just getting my thoughts together. I will try to answer each of your critiques in order: 1. Yes, 100% I would normally crop this image. I chose not to in this case because I wanted to show how flat the field was using the ring/gear method focus with the ASI EAF with the 135 mm lens. Obviously not a perfectly flat field and will continue to work on focus and getting flats more fine tuned. 2. I feel the stars definitely drown out the nebula signal. I fight over reducing stars a leaving tiny gray blobs that look like noise. This is only the second 135 mm image I have edited, the other was a quick OSC of Rho Ophucus from last May: https://www.astrobin.com/jqtgyd/B/. I have fought the same battel with my RASA8 at 400 mm focal length. My H+OSC image of the Lagon Nebula shows some of my attempts compared: https://www.astrobin.com/4ywcop/B/ using masking and range selection. I did the same process with my SHO version of the lagon, but did not take the comparison clips. There are also more comparisons of my 2020 vs 2021 version of the Heart Nebula in OSC and Ha+OSC. That said, I love the concept of a softer stretch star image and placing those stars into a starless version of starnet. Thankfully, starnet runs so quicly through a GPU acceleration method of my machine that I learned from another member of the community. I will probably try this method tonight as the clouds as always are more than predicted. 3. I agree again, way to much noise in the image for me. I need to go back with a more thorough attack and not just run TGV denoise once at the end. I will also probably suppress the black point further to hide more of it on my next edit. Do you have preferred denoising plan for your images? I have definitely enjoyed all of your latest work! 4. I need to adjust the curves here again and darken some of the more faint gas to give better contrast. On this run, I wasn't sure how far I could push the contrast with data collect with a lens. 5. Finally, I think your comments were great and what this group was designed to do. I chose this image because it was it's first run for me using 1x1 bin 2.3 um pixels on the ASI 294 MM. The files sizes are little silly at 90mb a peice. I am going to need a another external SSD just for this camera binning. And yes, flats are a definite! I just ran out of initial storage after image capturing to get 30 flat subs for each filter that added up to 8.1 gbs. ( I use 30 as number simply because in statistical methods you need 30 occurrences of an event to have enough power to determine random vs nonrandom outcomes) Thanks again and sorry for such a long reply. I am going to post again to the group regarding my combined Lum+SHO rosette and would love to hear your feed back on it as well. CS! - Brandon |
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Hi Brandon, happy to see that my comments came across well. Overall you have to see that this image is really nice, and that is 1st of all the most important thing 😉. Interesting for me was that you used TGV denoise and now that I know it makes actually sense what I see with the noise level in the background. I moved away from this method since I was never really satisfied in what it produced. I strongly assume that this is because I do not do it quite right, there are so many parameters and techniques that one can use, and it is always difficult to find the best setting for each image. I watched a bunch of YouTube videos about it, and they pretty much confirm this, very different suggestions what to apply and what not to. Right now (and this can change at any time if I see some other technique that I like) I dominantly use the Multiscale Median Transform routine. There are also a LOT of different settings for this one, and I experimented quite a bit. All in all I found a setting that I like most, not too aggressive but still working well. You might want to give that one a try:  The mask for this is an STF stretched image (inverted) that was stretched even further to roughly 3/4 of the Histogramm at the peak. The mask is important since it tones down the aggressiveness. The blotches with Starnet are always a menace, did and do not like them, who does 😉? I found out that the StarXTerminator tool produces at least for me a better starless image, but has also the problem of the leaving behind those blotches. Those can be handled though with Topaz very nicely, I just found that out recently since I do not have Topaz for long. One has to be very careful with this tool since one can overdo it very quickly. But to get rid of those artifacts from star removal it looks like that it works really well. CS!! Uwe |
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| Thanks Uwe! I'm absorbing all this also. Just this first thread has made this group worth it! |
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Uve, how is your life coaching? Because your astrophotography critiques and recommendations are remarkable!!!! Thank you so very much for taking time and sharing your denoise process. After fiddling around with MMT setting for my images, it made an incredible difference without taking way from the high SNR areas. Also, adding a less stretched star image is an absolutely brilliant way to limit the small stars that overwhelm the field. Here is a more blue toned version of my previous Heart and Soul Image cropped with your recommendations. Thank you again for your assistance! -CS!!! -Brandon https://www.astrobin.com/1qox8p/B/ |
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| No problem Brandon, this is all what it is about. Love to help, makes me happy! Don't forget, this is just the beginning, I am still way behind a lot of others here, I call them the Pros 😊😊😊. But as I wrote before, most important is that you like the image. When I look over mine I am always amazed how much we can do from the backyard!! I started Astronomy when I was 10 years old, inspired by an image in a book of the Trifid Nebula. And if my memory does not trick me, I think my image now that I took last year is so much better, amazing the progress in technique. I wonder what it will be in another 50 years. This experience at that age determined my life, I knew that I would study Astronomy already at that time, and as a stubborn German (as my (American) wife always says 😊) I did not let go. Was a great decision, never regretted it! I will look out for your next images! |
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| One thing I do like about this avocation of a lifetime is that we will never get to the finish line...there will always be something to learn, study and enjoy! Thank you all for being a part of the journey. -john |
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Another thing worth looking at is the EZ processing suite of tools in pixinsight. They can save you a lot of time with all the settings and allow you to try different approaches without getting lost in all the details, but you can go get pretty deep into them if you want. They do use tgv denoise and MLT for denoise but you can change the settings quickly and detune one thing or push another, but a lot of those boring steps are done for you. It makes the trial and error process less tiresome. For deconvolution, the EZ suite doesn't have de-ringing so if you have an image with big problems you have to go back and do it manually. For adding a little contrast, look into the script under utilities darkstructureenhance. Sometimes it can punch up some of the dark details. Of course, the colormask script is another favorite of mine. It allows you to choose more specific colors to enhance or diminish. I agree that StarXterminator is much better than Starnet, but not completely perfect either. There's still things to work out when you have bright star halos. The GAME mask creation script can help mask those (which you invert) allowing you to focus on fixing them. I think you have a nice image and you've done a nice job with it. I look forward to seeing what you do with it. CS Tom |
