Would my guide cam benefit from an IR Cut filter?

[Skipper Billy]

I am using a ZWO ASI 290MM (full size) camera on a SW Evostar ED72 as my guide scope.

Would it benefit from an IR Cut filter in front of it ??

It would have to be a T2 size filter as its an all screw together train. (Hard to find!?)

[vlaiv]

In principle it might. Longer the wavelength of light - less bending there is, so in IR you should be affected by seeing the least. You will loose some of camera sensitivity, but that should not be an issue with longer guide exposures.

You don't need any special T2 size filter - regular 1.25" filter is enough, you only need an adapter like this:

https://www.firstlightoptics.com/zwo-filters/zwo-t2-to-125-filter-holder.html

In fact, you might have received one with your camera already (I know I did for one of my ZWO cameras).

[vlaiv]

Ah sorry

I thought you were asking about IR pass filter (did not read what you've written properly).

No, IR cut will not be much of a use for guiding. Even if stars are a bit bloated it does not matter for guiding.

Anyway, you can use one of those adapters if you still want to try some sort of filtering on your guide scope (either IR/UV cut or IR pass filter).

 

[Skipper Billy]

@vlaiv Thank you 🙂 

[Merlin66]

I found to get better star images (for plate solving) that I had to fit a UV-IR filter to my ol' DMK cameras when used as an efinder on the 60mm finder.

A couple of exposures will quickly show the difference, if any.