Thread: Spider Season.
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Old 03-12-2023, 10:13 PM
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Peter Ward
Galaxy hitchhiking guide

Peter Ward is offline
 
Join Date: Dec 2007
Location: The Shire
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Quote:
Originally Posted by alpal View Post
Hi Peter,
no -
I put each of all 5 stacked and registered frames into NASA FITS Liberator
to do the stretching for me.
I suppose that normalises the output due to high compression?

Did you allow for the sensor's spectral sensitivity and filter transmission?
Most sensors drop away from the peak quantum efficiency for Blue and Red.
So anyway -
I am now looking at 5 pictures of LRGB Ha
and they all have strong signal.
I think I would know if the output was wrong as
the White balance would be out?
Bright stars come out as White - usually - although
that can be from exceeding the well depth.

cheers
Allan
I didn't invent the physics. It was tried and tested long ago.

You've already noted that blue and red ends of a sensor have lower QE...hence you need exposures to account for this get a correctly balanced colour exposure.

As I mentioned, shoot and process a colour test chart and get a handle on both filter curves and sensor QE. You may be surprised how colours don't match the chart when its held next to a monitor.
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