Amp glow not removed
For some reason amp glow is not calibrated out of the final integration image.
My data set has Light, Dark, DarkFlat, Flat, Bias frames.
Camera: ASI 294MM Pro. All frames were shot at Temp=-20C, Gain=250.
I provided the link to download master files and final integration. Amp glow is on both sides of the image due to meridian flip. I also included integration created in DeepSkyStacker which also has amp glow.
Please help me find what the issue is. I'm happy to reshoot dark and bias frames again if necessary.
I chose cosmetic correction (hot pixel kappa=3, cold column kappa=8, hot column kappa=8), 32-bit masters, Scale MasterDark and Scale MasterFlat, Adaptive Pedestal=on. Let me know if additional files are needed.
software version 1.08.3 beta 2
Hi Maxim, I'll have a look. Thanks for sharing the data!
Adding to that, can you upload like 20 light subs at least? Just 1 won't work very well I think for calibration purposes.
@vincent-mod Hi, Vincent. Are you trying to reproduce it? I thought you can tell what's wrong just by looking at the FITS headers...
I uploaded all Ha-subs in a ZIP file. It's rather large at 1.7GB. Same link.
FYI all master files were created using "automatic" integration; cosmetic correction (hot pixel kappa=3, cold column kappa=8, hot column kappa=8), 32-bit masters, Scale MasterDark and Scale MasterFlat, Adaptive Pedestal=on.
Yes, I'm trying to recreate and see what's happening. 🙂 Thanks for uploading. Please allow for a day as it's rather busy at the moment, but hope to have an answer faster. And just for my clarification; you created the master files on automatic mode right? The other settings you post are what you did afterwards. Scaling means you didn't have darks for the exposure you used I guess then. That may be the problem as amp-glow is not behaving linear and scaling that doesn't work well.
And apart from that, I don't see a MasterDark?
My bad. Here you go.
Thanks, will have a closer look at it today.
Ok, had a look and I'm not seeing a big issue. I loaded in 15 of your first lights, added the master calibration files and loaded 1 light to check how the correction is working (top of APP window, switching the view from linear(l) to l-calibrated) and that showed this;
Linear, non calibrated view of a single sub:
Calibrated view of a single sub:
And then the integration of all 15 lights:
What? How? Did you use different settings than me? Can you try stacking all subs? Maybe there are a few than throw off the averages... I'm getting
for my Ha, O3, S2 stacks 🙁
Try stacking the first 15, those I tried. I simply loaded those in, added the master bias, master dark and master flat, went to tab 6 and pressed integrate. 🙂 I'll try all the subs.
All subs you send from just Ha:
So must be a setting you changed I think. Or a workflow issue.
@vincent-mod And that was with "automatic" integration or "average" with local normalisation? Adaptive Pedestal on or off? "Align channels" and/or "Remove Light Pollution"? Normalisation: "regular with multi-scale and BWMV" and "neutralize background"? MBB and LNC? No under/overshoot?
I can try "automatic" since I don't have any satellites or meteors in the subs so may not need sigma clipping... But I thought it's just the ADU difference between MD and Light frames or MD, MB and Light frames.
I'll try smaller stacks too.
@vincent-mod Am I doing something stupid then? Do I need to uncheck all calibration frames and leave only masters checked because maybe it's over-correcting when both calibration frames and masters are checked?
Completely automatic, standard settings, no LNC or MBB even. Sigma clipping is also done automatically, you never have to change that, unless you still see a trail for instance. Adaptive pedestal is also standard on, so no need to change anything.
So to recap;
0. Start APP (restart if already open to reset settings)
1. Load all H-alpha lights and master calibration files (use the master buttons)
2. Go to tab 6, press integrate
Thanks. I could not work out what setting was causing this. When I have only light frames and Master calibration frames selected the integrated stack image comes out clean just like you had. My hunch is that I initially had both masters and individual calibration frames selected which caused over- or under-correction.
I was able to reproduce it by checking "Scale MasterDark", "Scale MasterDarkFlat" and "align channels" and "split channels" boxes, having subs for all 3 filters selected along with corresponding master calibration frames.
Is this a bug or a feature?
That may be, why are you scaling the darks in those cases? As I mentioned, scaling a dark doesn't work for amp-glow as that doesn't behave properly in a way that APP could calculate what it would be. To make sure you prevent this, I would work on each filtered data separately and then use the final integrations (without calibration data) to combine.
@vincent-mod I guess I misunderstood the tooltip on “scale MasterDarks” box - it seemed like scaling improves the matching. Thanks for the explanation.
No, scaling is for the case that you have lights that have a different exposure time than the darks. When the dark has no amp glow, you can scale it to still work.
And, you're welcome!