Is my ASI174MM fitted with an IR filter

drrobin

Hi,

If I hold my ASI174MM up to the light and reflect light off the optical window it appears slightly red, whereas my ASI120MM-S has no red reflection, so it looks like my ASI174MM is fitted with an IR filter.

Should I see a slight red tint with reflected light from an ASI174MM?

The reason I ask is that when using it for Halpha, I see an uneven field, rotating the camera on the Halpha scope and the uneven field rotates with the camera, so it isn't the scope.

Thanks

Robin

Sam@ZWO

Hi Robin

AR coated window reflect a little red too in some angle

you can get the protect window out and test again if you suspect it is the reason of uneven filed