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Filters, filter wheels and filter sizes


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I have a ZWO ASI1600mm PRO camera and I'd like to start using it with photometric filters in a filter wheel.  I would like to use a manual filter wheel but they all seem to be for 1.25 inch filters which look too small to go with the ASI1600. I actually took one out of it's mount and the actual piece of glass was 27.75mm diameter rather than 31.75mm so a bit smaller than 1.25inches. What size filters do other people use with the ASI1600?


The filter wheels seem to take unmounted filters but most filters for sale seem to be mounted so does that mean you have to take the filter element out of mount?





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Never heard of any-one removing the filter from it's mounting.  They are either Mounted filters, or unmounted filters.  I have had both types over the years.  1.25" is certainly a lot cheaper.


I have also tried manual filterwheels.  They do work OK, but the drawbacks are:


1. Having to change filter manually and this is not always easy in the dark, and sometimes depending on the position of your scope you cannot see without being a contortionist (I even had to lay on the floor once to see what filter I was changing too!!!).  


2.  Because of the hole for the wheel to select which filter you are using, they can leak light.  Generally this is not a problem at night, but if you want to take Flats in the daytime, you will need to cover up your filterwheel. 


If you're only going to be taking one filter per night then it will work just fine.





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The link that Terry sent me showed that the 1.25" would be too small so I think I'll need the 31mm ones.


The filters I'm interested in are the Baader Photometric and the photo on the FLO website shows all sizes mounted so I contacted FLO about it. They said the 1.25" are mounted but the 31mm and 36mm come unmounted despite what the photo showed. 




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