Anomalous L channel...
 
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Anomalous L channel integration - suspect normalisation issue


(@mestutters)
Red Giant Customer
Joined: 5 years ago
Posts: 137
Topic starter  

Hi,

I was processing a set of LRGB subs yesterday evening and encountered an odd result in the L channel.  R, G and B all look OK.

Screenshot 2021 04 23 07.50.23

 

While checking my input L subs I observe an issue with a few (c10-15  of 58) of them, when changing the viewer mode from 'l-c-registered' to 'l-c-r-normalised', so I suspect something is going amiss during Normalisation.

L-C-Registered:

Screenshot 2021 04 23 08.00.22

L-C-R-Normalised:

Screenshot 2021 04 23 07.59.58

I have processed c60% of the input subs previously without issue but managed to grab a few more during a recent clear night.   The calibration frame have all been used previously with other images without issue.  I ran the integration a second time with the same result.  Prior to starting this integration, I had done another target without issue and had simply cleared the previous subs and changed the working directory before starting NGC4244. 

I plan shortly to re-boot my lap-top and do a further rerun to see if the issue is still present.  


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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4736
 

Could you check the offset you used for the subs and the calibration data?


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(@mestutters)
Red Giant Customer
Joined: 5 years ago
Posts: 137
Topic starter  

Hi Vincent,

Having rebooted and restarted APP the integration the results now look as expected. 

Screenshot 2021 04 23 10.06.05

I have no idea why it was only the L channel that had this odd result, or why it seemed to be only a small number of L subs that displayed very high contrast when switched to L-C-R-Normalised mode.

I guess there must have been some sort of initialisation or other transient issue as a result of switching targets without first restarting APP.

I have a CCD camera so offset is not something that I can set.

Regards

Mike


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