Filter question ... - Forums

Topic starter

Sep 30, 2023

Filter question: I have an astronomik h-alpha 12 nm filter for use with my (unmodified) canon 70d dslr camera. Will this work with my asiair mini? or will everything be so dark that the guide camera wont be able to see enough stars for polar aligning and plate solving.
Thx for reading.

Rodrigo Roesch

Sep 30, 2023

Most likely it won’t work since most of the Ha will be rejected by the stock filter that is in front of the sensor. So the small amount of Ha that passes will also depend on what telescope you are using, but also will require longer exposures. You may want to do your Pa without the filter, but focusing with the Ha on may be a challenge.

Sean Mc

Sep 30, 2023

I say give it a try. It’s a full moon so you have nothing to lose.

Bob Lockwood

Sep 30, 2023

Not that I would know, but a 12nm Ha is about as light as they get, you may be surprised what will pass through it.
Try it, and if it works, your good to go.

Oscar

Sep 30, 2023

Firstly, unless you are using an OAG, the guide camera is unrelated to your main telescope; that means a NB filter would not affect guiding performance for the guide camera. Secondly, and most importantly, It's not a good idea to use an H-a specific filter or even a broader dual narrowband filter like an L-enhance with a stock DSLR (stock means unmodified). The built in IR filter of the unmodded DSLR will block most of the Ha from coming through.

Read this forum post and thread https://www.cloudynights.com/topic/845755-filter-ideas-for-a-stock-dslr/#:~:text=A%20narrowband%20filter%20will%20not,the%20Ha%20from%20coming%20through.

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