Having some problems again with wipe.
After doing autodev, I get this uneven glow (see attached) that doesn't look like vignetting or gradient, both gradient and vignette wipe given strange uneven results.
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Bortle 8-9 zone
Tracked with star adventurer
Sony a6000, ISO400
Lights: 66 x 60secs
Darks: 20 x 60secs
Flats: 20
Bias: 24
Hi
First thing to do when you first load an image is to:
BIn (optional)
Autodev (it will not look pretty yet but will reveal stacking artifacts)
CROP (mandatory to remove stacking artifacts)
now you can WIPE
Well done for taking flats but if you make effort then do take dark flats ([put the lens cap back on and shield the lens (I shove a lens bag over it)
@happy-kat
Yes that's the process I followed to process this image. Do you know for the wipe modules, would a gradient wipe or a vignette wipe be more suitable?
I also did take dark frames with a lens cap on.
Thank you for uploading the dataset - it is very helpful!
I got a feeling the flats are not doing their job correctly. It is quite rare for a well calibrated image of the night sky to show increasing gradients towards the edges of the frame, though it is theoretically possible under special circumstances (placement of light domes) under heavy polluted skies like yours.
What does the dataset look like without any calibration frames? (e.g. just the lights)
I can't get Wipe to output anything useful and it yield "shadows for bright objects - it is almost like you stacked some lights along with the flats when you were creating the master flat?
Ivo Jager StarTools creator and astronomy enthusiast
admin wrote:Thank you for uploading the dataset - it is very helpful!
I got a feeling the flats are not doing their job correctly. It is quite rare for a well calibrated image of the night sky to show increasing gradients towards the edges of the frame, though it is theoretically possible under special circumstances (placement of light domes) under heavy polluted skies like yours.
What does the dataset look like without any calibration frames? (e.g. just the lights)
I can't get Wipe to output anything useful and it yield "shadows for bright objects - it is almost like you stacked some lights along with the flats when you were creating the master flat?
@Ivo: I think you're right! The 'light frames only' autodev looks more even now without the flat frames!
But it revealed lots of dust spots on wipe.
Is it worth it to retake flat frames now?
celeron787 wrote:
@Ivo: I think you're right! The 'light frames only' autodev looks more even now without the flat frames!
But it revealed lots of dust spots on wipe.
Is it worth it to retake flat frames now?
I think you are using a DSLR lens, correct? Then it should be safe re-taking flats, else you can only take flats if your camera is still attached to your scope in the same position when you took the light frames.
It'd be good to figure out what went wrong with the original flats though...
Especially since they almost - I could be wrong - seem to include signal from the lights, as if you accidentally included light frames into your flat frame stack.
Ivo Jager StarTools creator and astronomy enthusiast
