MD not created even though Darks present  

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(@rowland-f-archer-jr)
Main Sequence Star Customer
Joined: 1 year  ago
Posts: 45
July 16, 2018 23:52  

I have a rather large project loaded - 861 Lights, 167 Flats, 125 Darks, a MasterBias and a BPM.

There are five sessions and 7 channels - LRGB and SHO. 

There are four exposure lengths in use:  1 second, 10 sec, 60 sec, 300 sec.  The object is M42 and I shot some 1 sec L's to try and get some definition in the bright core.

I had 10s, 60s and 300s darks and they are all loaded.  The darks are assigned to All Sessions and All Channels.  I didn't have 1 sec darks so decided to give it a try and when prompted, told APP to use the 10s darks.

I clicked Calibrate.

Although I shot all light and calibration frames with Gain=200, APP prompted me to ask which dark frames to use, saying the Light was Gain zero.  I assigned the appropriate dark frames for the 10s and 300s lights.  When APP prompted me for the 60s RGB frames, it only offered the choice of a 300s or a 10s MasterDark.  I assigned the 300s MasterDark, and when the calibrate step finished, it showed the 60s frames with this 300s MD assigned, and scaled.

My question is - why wasn't a 60sec MasterDark created and used?   I have not closed the project so if there's anything I can provide to help, let me know.

Thanks,

60s darks loaded and selected
No 60s MD available to assign
no 60s md created

Rowland


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(@mabula-admin)
Quasar Admin
Joined: 2 years  ago
Posts: 1799
July 19, 2018 22:47  

Hi Rowland @rowland-f-archer-jr,

If you load darks and assign them to the same channel and session, they will be combined to 1 Masterdark for all darks that have the same ISO/gain.

I notice from your screenshots that not all darks have the same gain: 200 & 201, so since you assigned all darks to the same channel and session, APP created 2 Masterdarks, one for gain 200 and 1 for gain 201. So the 60sec darks should have been integrated into the 201 gain Masterdark together with the 10s darks.

If you want to have a 10s, 60s and 300s masterdark to be used for all sessions, perhaps, it's best to simply create them first before starting with the multi-channel /session workflow.

Regarding the gain reported for the light, does APP correctly show the gain for the light frame in the frame list panel? Or does it show 0 as well ? (perhaps a small bug here)

Cheers,

Mabula

Main developer of Astro Pixel Processor and owner of Aries Productions


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(@rowland-f-archer-jr)
Main Sequence Star Customer
Joined: 1 year  ago
Posts: 45
July 19, 2018 23:37  

Thanks Mabula. 

Good question about GAIN in the FITS header.  I've never used GAIN = zero with the ASI1600MM so I was surprised to see that show up in APP.  I looked at the FITS header and MaximDL recorded an "eGAIN" value of 1.0, but there was no GAIN tag in the FITS header.  Last summer when I was using SGP, the GAIN value was recorded, but it looks like MaximDL is not recording GAIN.  I'm assuming APP decided that no value for GAIN meant GAIN = zero, a reasonable assumption.

I'll have to investigate what MaximDL is doing.  I always include the GAIN value in my filenames so I have it there for reference, although I know APP can't use that.

Regarding the GAIN value of 201, I can't seem to get the slider in the ZWO Ascom driver to settle on 200, so I left it at 201 as the closest value.  Looks like some earlier frames were shot at 200.  

Thanks,
Rowland


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