1.25" filter wheel and the ASI183

[harry1969]

Hello, I'm  experimenting with a DIY filter wheel for an ASI183. I currently have the MC version but am considering getting the ASI183MM so am trying to save a few pennies by building my own filter wheel. I've mounted a stepper motor directly to the shaft of a manual 5 filter wheel but the motor placement means I need to add an extension tube so the camera doesn't foul the motor. Does anyone know how far away from the filter wheel the camera can be before it causes problems with vignetting?

 

Thanks.

[JamesF]

2 minutes ago, harry1969 said:

Hello, I'm  experimenting with a DIY filter wheel for an ASI183. I currently have the MC version but am considering getting the ASI183MM so am trying to save a few pennies by building my own filter wheel. I've mounted a stepper motor directly to the shaft of a manual 5 filter wheel but the motor placement means I need to add an extension tube so the camera doesn't foul the motor. Does anyone know how far away from the filter wheel the camera can be before it causes problems with vignetting?

I'm fairly sure it depends on the focal ratio of the OTA.

Could you not mount the motor on the other side of the wheel?  Or perhaps drive the edge of the wheel rather than the centre?

James

[The Lazy Astronomer]

Input your details here: https://astronomy.tools/calculators/ccd_filter_size

Remember that the clear aperture for 1.25" filters is less than than 1.25" (measure your filters).

I had a play around with some numbers, and you could probably get away with around 60-70mm filter to sensor distance (at a fairly typical focal ratio of f6).

[harry1969]

On 04/02/2021 at 01:00, The Lazy Astronomer said:

Input your details here: https://astronomy.tools/calculators/ccd_filter_size

Remember that the clear aperture for 1.25" filters is less than than 1.25" (measure your filters).

I had a play around with some numbers, and you could probably get away with around 60-70mm filter to sensor distance (at a fairly typical focal ratio of f6).

Thanks, that's perfect. I have a good bit of headroom to play with re. filter size - I'll not have to move my motor.

Edited February 5, 2021 by harry1969