Is 1,25" EFW compatible with ASI294MM?

Hara

I have now ASI183MM and 1,25" 8 slot EFW. I am planning to update the 183 to ASI294MM. Is the 1,25" EFW compatible with it, or does it cause vignetting? do I have to sell it and filters too and buy 2" ones?

Tech@ZWO

Hara It also lies on your telescope.
Here for your reference.

Hara

If I read this table correctly, it is not compatible using my Sky-Watcher Esprit 100 f:5.5 and Sky-Watcher Quattro 200 f:4? you mean with maximum that f-number must be bigger than that in table?
But if I use in same filter wheel with 31mm frameless filters, instead of 1,25" filters with frame, it IS compatible? both filters, 1,25" and 31mm, can be installed into that EFW....

Tech@ZWO

Hara If the focal ratio of your telescope is f/5.5 or f/4, it may has vignetting when you use ASI294 and 1.25" filter.

Hara But if I use in same filter wheel with 31mm frameless filters, instead of 1,25" filters with frame, it IS compatible? both filters, 1,25" and 31mm, can be installed into that EFW.

Yes, 31mm filters can work with ASI294 on an f/3.7 telescope without vignetting.

tareqphoto

If i read the table correctly it means that 1.25" filters is ok with ASI294MM as long you can get them closer to the sensor, if you using a filter wheel that is not much closer, if you use one filter then place it on the camera AR window and you are like having 31mm there, because the edge mounted of 1.25" is going to introduce vignetting at that distance from camera with filter wheel, 31mm will be fine at that distance and filter wheel, in both cases even if you use 1.25" you can easily remove vignetting with flat frames.

Hara

tareqphoto
Filter wheel is/will be located as close to the camera as technically possible. Camera is threaded directly into it. My narrow band filters are framed 1,25" versions, so those must be changed into frameless 31mm versions when updating the camera to ASI294MM.