Does the zwo 120mm mini have an ir cut filter over the sensor?

[alacant]

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Edited April 25, 2020 by alacant

[Tomatobro]

No

[PEMS]

It seems that as a genarallity the mono ones have an anti reflection coated glass cover and the colour ones have an IR cut filter as standard.

Makes sense as your OIII should not be passing IR through to the sensor, and if you wanted to obtain IR images then you do not want an IR cut filter in place. lso saves ZWO money I would expect.

[alacant]

My 60mm guide telescope produces fat stars. The uv-ir cut filter reduces their size. 

I wondered if filters were necessary.

Thanks

[vlaiv]

21 minutes ago, alacant said:

My 60mm guide telescope produces fat stars. The uv-ir cut filter reduces their size. 

I wondered if filters were necessary.

Thanks

For guiding only - not really. Guiding may even work better if there is more light and that light is spread over more pixels.

Sometimes one can benefit from slightly defocusing guide star - that is the same thing as not using IR/UV cut as IR and UV light is out of focus

[david_taurus83]

I have a small 32mm guidescope. It produced fat but also dim stars. I added a cheap ZWO ir/uv filter to the 120 nosepiece and it tightened up the stars nicely.

[alacant]

1 hour ago, david_taurus83 said:

dim stars

Thanks, yes. In PHD2, in my case HFD 5 to 6 to  -> 3 to 4. The screen is now noise free too.