Icesheet

Bear with me here there were a lot of firsts for me for this image. First galaxies imaged outside of M31. First full workflow with all pre-processing and processing done in PixInsight. A lot of new processes, pixel math etc. First time analysing FWHM and eccentricity. I'm not unhappy with the outcome(s) but I'm sure there's more to be had from the data as well. Data captured with Esprit 100ED and Zwo ASI1600mm Cool. L: 100x45s RGB: 20x120s Ha: 8x300s ~4hrs integration Calibrated with Darks, Flats and dark Flats Workflow (followed basic workflow outlined in Mastering PixInsight book): Weighted Batch Preprocessing Crop DBE (on each individual channel) Combine RGB Colour balance and Background Neutralisation Stretch RGB, L and Ha Curves and Colour saturation LRGB combination SCNR to remove green Noise reduction HDR compression Pixel Math to add Ha to Red channel The biggest issues I have had were with Dynamic Background Extraction. There were apparently some crazy gradients (see below). I struggled with it a long time until I found something I could live with but that came at the expense of some background detail I could see was there. I've now since learned that it may be because of the IFN in the area. Can anyone comment if the background model below might show that and if there is anything I can do in DBE about it? I saw similar in all channels. It would be great if I could recover some of the background detail. Maybe I can't get the IFN but I think I could bring out more of Holmberg IX (?) just below M81. I actually have another 4hrs of data from the night before but I left focus the same all night and it drifted quite a bit with temperature changes maybe i could add that too. Also can anyone comment on the FWHM and eccentricity plots. I've read anything under 0.4 eccentricity is considered good but does the distribution of it across my sensor tell me anything bad or good? My FWHM seems to drift from left to right. The next biggest issue was adding the Ha data and perhaps I should have added it earlier. I could not get all the stars removed using PixelMath. It has definitely added something to the galaxies, not as much as I had hoped but it's there. Unfortunately it has affected star colour to the extent that I think I prefer the LRGB version. If anyone has any tips on adding the Ha I would appreciate it. Finally, if anyone is really interested you can have the data to play with. I'd be really interested to see what someone with more experience could get from it. Thanks for looking and please let me know what else I could do.

In case anyone else has this question Zwo support replied to me. Hello Chris Recommend to use the same specification（all mounted or all unmounted ）

Good luck with it!

There is a link on the ZWO ASIAir Pro page to a GitHub page where someone has seemingly found a solution to problems communicating with the EQ6R. Not sure if this is the same problem with you but worth a try I guess. https://gist.github.com/timucingelici/217ac492bc2b127c6645ce033463d265

Wasn’t sure where to put this but I’m wondering if anyone knows if it’s possible to mix unmounted and mounted filters in the ZWO filter wheels which accept both? I have a full set of 31mm unmounted filters which you have to secure with some screws and washers but then it looks like it would not be possible to thread a mounted 1.25” filter due to overlap of the washer and screw. Wondering if anyone knows if this is possible or if there is a solution to it if it isn’t? Picture below that might help If I’m not being clear.

I’m not familiar with the Altair range but if they are basically the same as the ZWO equivalents then I think they will be very well suited to the RASA. I’m sure Altair would be able to confirm 👍🏻

Edit. Deleted just realised this was an old post

I actually think I know what happened now. It seems I used the STF auto stretch on the histogram transformation process. However, for some reason this stretch pulled the midtones all the way over to the left of the data. It didn’t look like that on the image on screen though and not being familiar with the histogram on PI I didn’t notice this. At least that’s my working theory just now.

I’m looking forward to learning more despite my mishap! Plus I’ll always have PS anyway as my wife uses it for her photography so should have best of both worlds. Have now also ordered the Warren Keller book and the new Rogelio Andreo one so will have plenty to keep me going!

Thank you! I'm glad you were honest as now I know something has gone wrong somewhere and I don't need to worry about blinding everyone with my pictures 😉

I think that is what I may well have done. Just looked back at the tutorial I was following and it mentions removing the STF autostretch before applying histogram transformation. It looks like I probably didn't. Back to the drawing board.

Thanks. I'll definitely look into that book. I can already see it has unbelievable functionality. I also read most people use it along with photoshop, I will need to try and find a PI/PS workflow. I actually just saved as TIFF from PI and opened in PS. Wow. I nearly burned my eyes out with the core and the histogram is way to the right. I've obviously done something wrong somewhere. Lesson learned, check these things before you post them!

Hmm I just checked on my computer. On PI it looks good. For sure the Galaxy is a bit brighter along with background sky but overall a lot more detail and better colour. I opened the jpg I saved and it’s noticeably brighter there and here on my phone it’s even brighter again. The jpg of my earlier version on the computer lacks detail and contrast and seems to have a purple cast in the background sky. Here on the phone it actually looks much better. I have no idea what’s going on. As long as you like one of them I’m happy 😉

No it’s not haha 😆 it’s the bottom one! But, I loaded this on the computer and there it looks completely different. Looking on my phone now, I agree that the top one is better. Can I ask if you’re on a mobile device or a desktop? I’ve sometimes noticed differences before but nothing like this

I have been avoiding PixInsight since I started with astrophotography. Partly because of the price and partly because PS was a big enough learning curve for me along with everything else. Well, I decided to take the trial and see what I could do with existing data. M31 has been my reference point since it was my first ever attempt. In a little under 2 hours I produced, what I believe to be a better final product than all the fiddling I could do in PS. It's still not perfect, blown the core out more here, but to my eyes a definite overall improvement, especially with colour balance. Let me know what you think. Looks like I'll need to dig deep for another astro related purchase!

Wow! This is mesmerising. Absolutely the best image of this area I have seen. I now feel completely inferior having just posted my inadequate version before seeing this 😂🙈 Congratulations you have completed astrophotography!

First attempt at an HaRGB image and really struggled coping with the halos and microlens effect when merging Ha to the RGB. You can see the early result here. Tweaked away, failed at using starnet as was suggested but I have come up this now. I also think this is my longest total integration at 6hrs so all in all I’m happy for now. Definitely coming back to it later though! Any feedback welcome especially about the massive halos 🤬 50x180s Ha 70x60s for each filter in RGB Esprit 100 with Zwo ASI1600mm

Thanks for the reply. I have never used starnet actually but I will definitely give that a try. Yeah those halos are from the Ha filter but I can see micro lens effect in the RGB although that is a lot less intrusive than the halos. I also don’t like to overcook it but I think this just needs a little more. I’ll see how it turns out after trying starnet.

Ok thanks! As long as it’s not the equipment I’m happy. If I see it again at least I have can try to narrow it down a bit

Yes my target was rising as I was shooting. What effect could that be having? Something to do with changes in the atmosphere? Yeah I’m hoping it’s nothing to do with my equipment. I’ll maybe leave it all out for an extra hour before starting to shoot next time.

I’m wondering if anyone has a method to remove these horrible halos in photoshop? They are caused by my HA filter (camera ASI1600), a well known issue. My RGB image and colour looks ok but as soon as I paste the Ha as a luminance layer the halos and background take on a garish purple blue colour and tint that I can’t control. It’s also limiting how vibrant I can make the red/pink of the nebula. Anyone got some good tips?

When I set up last night I appeared to have developed some sort of aberration in my images that I hadn’t seen before. Almost like little tails on the stars all in the same direction. I spent quite some time checking everything to see what was causing the issue. In the end up I gave up and just decided to start imaging as it was only really noticeable when pixel peeping. When I checked my images later in the night I noticed they were gone. See below for a before and after crop. Could this be due to the optics not being cooled or could there actually be some sort of issue?

Thanks. I’ll look to see how much variation there is on temp on the FITS headers then. I need to shoot some new master darks so I might as well shoot them for -10 and see how it goes as you say. I’ll need to remember that next time I’m out.

I was imaging last night and set the cooler on my camera to -10deg as usual. However, towards the end of my session I noticed the camera thermometer was showing -13deg. Sure enough it was colder than -10 last night. I was planning on shooting darks today but should I shoot them at -10 or at -13? Anyone had this issue before?

I think it's fantastic that this service is offered, and it would really give me peace of mind but I must say I'm surprised that there is nothing official supplied with the scope to confirm this. Not that I would expect a detailed optical report but even just a piece of paper with the serial number of the scope saying 'Bench tested by Es Reid' with one of those digitised signatures. I wouldn't think that's too much to ask?