Did I get a bad R filter from Antlia? - Forums

Topic starter

Oct 21, 2024

I just got a LRGB set of Antlia V-Pro filters (1.25") and put them in my PlayerOne filter wheel.

I put my flat panel on top of my telescope and I ran the Nina auto exposure flat wizard and it came up with the following exposure times for my filters:

L: 0.60 seconds
R: 6.13 seconds
G: 1.88 seconds
B: 2.51 seconds
Now bear in mind this is a constant brightness light source from a flat panel.

I would expect all 3 RGB Antlia V-Pro filters to have roughly the same exposure time to reach 50% ADU since their bandwidths are fairly equal in size.

Do other people experience the too or do I have a bad R filter?

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Andrew Ford

Oct 21, 2024

I think this is some quirk of the QE/sensitivity curve of your sensor. They are not uniformly sensitive across the entire visible spectrum.

See diagram below I picked off google as an example for the 294MM and 1600MM

Miguel T.

Oct 21, 2024

I have to expose my Chroma R filter a little more than the others too.

Not only the sensor as mentioned, but how sure are you that your flat panel is sending equal signal across all wavelengths.

Brian Puhl

IOTD Staff

Oct 21, 2024

Probably your light source. Doubt it has anything to do with your filters.

John Stone

Topic starter

Oct 21, 2024

I've got the Player One Ares M Pro

Jonny Bravo

Oct 21, 2024

Your assumption that all filters should reach 50% in the same amount of time is incorrect. You need to consider the QE curve of the sensor as well as the light source for your flats. For example, I have the Poseidon-M and Astronomik Deep Sky RGB filters. I use a Gerd Neumann Aurora flat panel. LRGB flats I took:

L - 0.30"
R - 2.35"
G - 0.83"
B - 0.71"

The variation you're experiencing is perfectly normal. Nothing wrong with your filters

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Tony Gondola

Frequent contributor

Oct 21, 2024

You are looking for a problem where none exists, just start imaging.