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Looking at your layers you don't appear to have any curves, try adding some adjustment layers for curves and stretching the data by very gently dragging the curve upwards and slightly to the left. Stacking multiple adjustment layers is better than making big changes in one layer. Post the file up if you like, there are plenty folks on here happy to play about with it and let you know what they did. Ed.

That's a great image, well done. Welcome to Astrophotography Ed.

Beautiful Olly. 'Dunno what you are talkin 'bout, but beautiful

I just processed the "other" subs and I think I can see that at least one of the other two sets is out as well, not by as much, but noticeably. I left everything as luminance in APP just to get an idea. now I just need a clear sky to work out the correct offsets! Ed.

ah! I just found this....

Thanks for the input all. What do we mean by "offsets" ? is that separate focus settings for each filter? The optical chain I am using is an Altair Astro 102mm Refractor, then a field flattener then the filter wheel, then the ZWO 1600MM The focus controller is a Pegasus unit and I have it set up for various temperatures and equipment, I was thinking that I should use these settings for R, G and B prime focus and set the auto temperature compensation options I had set up auto temperature compensation on the last session by taking the motor position at 16c (25565) and the motor position at 13c (25385) subtracting the two (180) then dividing by 3 to get 60 steps per degree of change in temperature. Was this the right way to go about it? Other than this, I don't think ZWO ASI Imaging can control the Pegasus focus motor, at least it does not see it in the options, not that I have spent much time looking into it.

I have just finished removing and refitting the filter wheel, and to my surprise the channels were wrong, R,G and B in the filter software ( ASI ) did not map to R, G and B in the wheel, so that's obviously one problem, but more generally, do I need to be refocusing per-filter to account for the different wavelengths? Ed.

Hey folks. So I am starting my 2021 season with the ZWO 1600 mono that I got at the tail end of last season, I never really managed to give it a good run out at the beginning of the year. This morning I have 10 x 300 second exposures on M31 in L R G and B. I figured I would try something relatively easy to get the gear dialled in again as I have added a bunch of toys over the summer including a pier and a polemaster so I am happy with longer exposures, Combining these in APP there's a horrid green halo around everything and if I look at the subs the G channel does indeed appear to be out of focus by some margin. The problem is the last blue frame and the first green frame were taken back to back, the focuser is on auto-compensate, dew straps are on and most critically I am at this point asleep in bed grabbing some Z's and waiting on an alarm to tell me its done. Any ideas? I am going to pull the filter wheel out and look for smudges and grease on the green filter but are there any more experienced folks able to come up with more technical explanations as to why two back to back frames look so different? I have attached the last blue frame and the first green frame for reference. Cheers. Ed. Light_M31_300sec_Bin1_filter-Green_-10.0C_gain0_2021-08-29_001855_frame0001.fit Light_M31_300sec_Bin1_filter-Blue_-10.0C_gain0_2021-08-29_015857_frame0010.fit

Nothing to be ashamed of there mate. much better than my first attempts at Jupiter! in fact I never really went back, focused on more deep sky stuff. Ed.

here we go. this is from APP -> FITS Liberator -> PS and I am fairly happy with is as a first stab at LRGB. Source data needs to be better but for that I need September to come rolling around Just practice I guess. On AstroStace's channel she downloaded some public data from AstroBin but it seems thats either moved or been taken away. anyone know where there's a raw public LRGB data repository?

Ahha, ok so I have used the ESA Fits liberator software to get the individual stacked channels into TIFF's that photoshop can read and I can clearly see that the Luminance and Green channels are out of focus. Red is ok, blue is not too bad, G & L are blurred. Thanks for the pointers. I also managed to work out why "merge channels" is inactive, you need multiple images open in PS before it enables that option. another win! Ed.

Fair enough, thanks. IIRC I shot red first, then green, then blue then luminance the next night. I don't think I re-checked focus between and the temperatures would have changed a bit. That possibly explains why red is cleanest. This object also moves behind a tree later in the sessions so I am not 100% sure that there's not a leaf or two interfering. If you can get that result out of that data though, it's obviously mainly something in my processing, my first time with APP, I used DSS for all the Nikon NEF shots so I freely admit I have no idea what I am doing in APP. AstroStace on YouTube has been helpful but, steep curve! Which processing package did you use for that image? is that Pixinsight? I can see from your sig you have plenty options to go with Ed.

On AstroNoodles thread on first images Iapa suggested processing a picture from your rig in it's polar aligned home position to check your alignment. As it happens I had such an image from the other night and the processing has come back with this: Astrometry.net submission 4459787 Erm, what does it all mean?? Ed.

hey folks. I recently got myself a ZWO 1600 mono and filter set to up my game from the Nikon D800E I had been using. I have only had one real opportunity to capture some data with it given the longer days but in processing that data I seem to be running into a problem I have attached the stacked FITS files, I am using astropixel processor and when I get to the stage of combining the RGB channels it's creating this which is, well its very green! is there something wrong with my source data perhaps? or a focus problem with the green data maybe? Obviously this is a new camera, new processing software, new workflow so I am not under any illusion this is going to be a one-click process, and I have very little data to work with but can anyone see anything fundamentally wrong in the individual channels? Ed. M101-ZWO-LRGB4-Blue-session_1.fits M101-ZWO-LRGB4-Green-session_1.fits M101-ZWO-LRGB4-Luminance-session_1.fits M101-ZWO-LRGB4-Red-session_1.fits

bit more like this?

Re-stacked in Astro Pixel Processor... I think this one actually is better..

Ah! I wondered what that was for! so, where I have captured an hour each of R, G and B on my M101, I should also add to that a few hours of Luminance? that might go some way to explaining the trouble I am having processing.

When you say 2 hours Lum, what is "Lum" ? is that the fourth filter that came in the RGB set? Sorry for the daft question. I only got my camera bundle a couple of days ago. amazing image btw!

it looks like, possibly, I don't need to check the reference frame, it keeps that little "I am a reference frame" asterisk when unchecked but I will see..... After work.....

ok so if I am interpreting this right, I am stacking all the red channel images and picking my best red frame ( for sake of argument ) and using that as a reference frame, then stacking all my blue channel images but with the one single red frame checked and set to reference, then repeat that with green channel to get three separate images, R, G and B channels that are aligned to the reference. That's what I am trying now

oh yeah and it's well worth mentioning that the max recommended cable length for USB3 is about 3M, but the max length of Cat5 ethernet is closer to 100M so, if you run ethernet back to the inside to your router from the laptop outside then you can just save directly onto the main machine with a writeable share.

If you are using Backyard Nikon or Backyard EOS as your capture for the DSLR you can simply tell it to save them to the main laptop inside anyway: I don't know if this is what you are doing, but there is no need to save them onto an SD card? Maybe I have this wrong, and you have a "disposable" laptop outside that you save onto... Ed.

Hey folks. I made the jump last week to a ZWO mono camera and filter wheel setup and I am quite pleased with the new, cliff like learning curve ahead of me, however I am now looking for some suggestions on how to align the stacked images. Searching these forums there are a couple of threads on it but nothing conclusive so far. I have installed Siril ( not a clue what's going on there ) and the ZWO ASI software ( seems pretty basic ) but neither of these packages has enabled me to line up the R, G and B channels to get into photoshop. The three stacked TIFF's are attached, you can see that they are not lining up correctly, I did 60 Red, then 60 green, then 60 blue, so, as this is unguided, there's some drift in the images. So, 1. What software options are there to align these three images and keep them separate, obviously I can stack them in DSS but that then means I can't get to the colour information? 2. Why is the green channel so much brighter than the other two? Blue.tif Green.tif Red.tif

+1 for those active USB repeater cables, exact same product I have, although I do use the power supply that came with it.

Is it still behaving oddly this morning? Another thing I did was get a sky app on a spare mobile then fettle a way of bolting it to the mount so I could see very roughly what the mount was pointing at. this allowed me to do alignment and slew-to tests during the day.