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Cant get rid of Amp Glow ?
Hi, I've been using APP for 18months or so with no issues, but over the last couple of days I've come across a problem. I use a ZWO ASI294MC Pro with a CLS/CCD filter, and never normally have an issue. A couple of nights ago I shot M101, with 19 Light frames at 300 sec, gain 120, and also 60 flats, 30 dark flats and 16 Dark frames, at the same exposure, gain and temperature and processed the lot in APP Ver 1.079.
No matter what I do I can't get rid of the Amp glow. I've attached a couple of files from un-processed files to show you.
I use an iMac 2010, with 16gb of ram and OS version 10-13-6 (High Sierra)
Any thoughts as to what I/The software is doing ?
Obvious things first: Did you check temp, gain, exposure time on the darks to ensure they're the same as your lights? Is "adaptive pedestal/reduce amp-glow" checked in the Calibration tab? (Unlikely long shot: Are your darks current?)
I'm running the 1.083 beta on Mac OS, but I haven't seen an issue once I learned to be scrupulous about those particular issues, and the 183 sensor has HORRENDOUS glow.
Your second image looks as if it's offset from the dark -- you can see two amp glow flowers in it. Don't know what might cause that but it's sure suspicious.
@rickwayne Thanks for coming back, the Lights and darks were all 300 sec at 120 gain, at -10 degrees . The darks were shot the following morning, in a dark box, to avoid any light spill.
I have checked the calibration tab and I do have the "adaptive pedestal/reduce amp-glow" ticked.
OK, that's my expertise-wad pretty completely shot. Moderators?
Another thing I've thought of - When I rotated the scope to take the flats and dark frames, the camera dropped off the back (no damage though) as the 2" adaptor needed more tightening (it's a new scope to me, still learning its ways !) I put the camera back in the same position, with the filter wheel in the same rotational angle, but any change to the optical train wouldn't affect the dark frames, which influence the Amp glow - at least that's my understanding. What controls the Amp Glow is Dark frames, or am I wrong ?
@grahamdevenishgmail-com You're right. Amp glow is affected by darks and the orientation or even the presence of a telescope won't affect those (apart from possible light leakage). Would you mind uploading your data to
using upload2 as username and password? Please create a directory called grahamdevenishgmail-com_amp_glow so we can have a look and help you figure out what's happening. Thanks!
@wvreeven Thanks, do you want the full set of lights, darks, dark flats and flats, or just a sample of a few? - or just the lights and the master files created ?
@wvreeven Hi, I've just uploaded 5 files of each Lights, Flats and Darks, and 9 Dark flats, named Bias. Do I need to send an email to support as well or can I assume youve got it ?
Thanks for your help, Graham
@grahamdevenishgmail-com Got it, thanks!
Hi, have you managed to have a look at this at all yet ? I had another go with M101 last night, with my TS71 APO Refractor, 9 lights at 600 secs, just with Dark frames. I noticed a couple of things, when selecting lights the APP defaults to Sulphur II Session 1, even though I haven't selected this as a channel ( I used to just hit return and APP auto selected "something ??".
Second, I've attached a .jpeg of last nights efforts, and I know its not the best and it needs flat frames, but there is no evidence of amp glow ! (Also cropped slightly as it vignetted).
The other thing is this time APP ran in about 10 mins, with the other data submitted to you it took hours !!
Both were with the same camera, a ZWO 294MCpro, through ASIAIR.
Hope this helps ?
@grahamdevenishgmail-com I have asked Mabula to have a look and unfortunately he hasn't had the time yet.
As for APP selecting SII, that should only happen if the FILTER keyword in the FITS header is set to SII.
The amp glow indeed looks much better processed so that indicates an issue with the flats.
@wvreeven Hi again, after you mentioning that the Flats could be an issue, I reran the original data without flats, it ran end to end in 10 mins and no amp glow - Looks like the quality of my flats was the issue !!
Thanks for your help !
@grahamdevenishgmail-com Hi Graham. Great, I am glad to read that you sorted out the issue.