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Filter sizes for photometry

MatthiasK
Affiliation
Bundesdeutsche Arbeitsgemeinschaft fur Veranderliche Sterne e.V.(Germany) (BAV)
Mon, 08/15/2022 - 14:57

Hello,

 

I've been doing DSLR photometry for a while but now want to also use V and other filters with my astro camera. Chip size is 16.05x12.61 mm.

I wonder if I would better invest in 2" filters or use 1,25". I have a V filter of that size and it seems to work well, but maybe I miss anything. Before I buy more filters I want to understand potential impact on photometry.

Thanks for any recommendations,

Matthias

Peter Bealo
Affiliation
American Association of Variable Star Observers (AAVSO)
Mon, 08/15/2022 - 17:09
I would think you'd use the…

I would think you'd use the same filter size that you use in your astrophotography. Unless you're thinking of upgrading to a larger sensor in the moderate future. The diagonal of the chip is 20mm, so a 1.25" filter may be sufficient.

Peter

spp
Affiliation
American Association of Variable Star Observers (AAVSO)
Mon, 08/15/2022 - 23:45
Filter size

Matt,

I'd suggest you stick with 1.25 inch filters for your current camera.   Buy a B (maybe also an I), then just start doing photometry.   I doubt that larger filters would make much (if any) difference with your current camera.

If you get new 1.25 inch filters try to get the same brand and type (colored glass vs interference filter) as your current V filter.  Search the AAVSO forums for more information on picking filters.  

Someday you may decide to get a new camera with a larger chip.  The experience you gain using your current equipment will allow you to make better decisions when the time comes to buy new equipment. 

Phil