📷 L.jpg
Weird cross pattern showing up only in the Luminance data, This is about 9 hours of data, 300 s subs, 585 sensor, on the quattro 150p scope calibrated with flats and darks.
Anyone got a solution?
Cross pattern in Luminance channel
Engaging
It is a calibration issue. Check the consistency of your calibration masters, in particular between bias, dark and flats. You also have additive signal there.
andrea tasselli · May 2, 2026, 05:33 AM
It is a calibration issue. Check the consistency of your calibration masters, in particular between bias, dark and flats. You also have additive signal there.
I am not using Bias frames, only darks and Flats.
For flats i am using SkyFlats without any diffuser in between like a T shirt. The exposure time is 0.2s per flat.
Are your flats dark-subtracted?
andrea tasselli · May 2, 2026, 05:39 AM
Are your flats dark-subtracted?
You mean dark Flats?
No did not use dark flats
The problem is i never had this issue with any color camera.
Hassaan Zaheer · May 2, 2026, 05:42 AM
You mean dark Flats?
No did not use dark flats
You should. Always. Or bias.
And much longer flats for this particular sensor.
andrea tasselli · May 2, 2026, 05:46 AM
And much longer flats for this particular sensor.
Got it.
ill try longer flats
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