They say the sensor on the ZWO ASI2600 has an IR Cut filter.  I took it to mean it is just IR and not UV also so I use the IR-UV filter.  I would like to know if anyone knows if an IR Cut filter is all you need with a refractor or if you also need the UV part.  My understanding is that you only need these filters with a refractor but if you use a catadioptric scope with a field flattener or tele-compressor that the glass elements of those additions also require it.  I would love to not use the extra filter.  My FSQ definitely needs a filter for bright stars.