Basically what it's about Asi is; I've been having trouble getting the colour balance right with my SAC 4.2, as you can see by the non-filtered images here and
here. The problem appears to be, for my simple mind, the infared "bleeds" into the green channel causing difficulties in balancing colour and reducing image sharpness.
I posed the question
here on which is the prefered filter, Baader UltraViolet and Infared blocking filter or an Astronomik Infared only filter. The outcome was inconclusive as it seems selection is based in personal preference. Also the graphs I posted on the second thread link show very little difference between the blocking characteristics of the two types of filters.
Anyway, in the end I decided to go for the Baader filter, as I could find the most information about it in regards to durability and scratch resistance, even though the cutoff profile was similar and the Baader was more expensive.
However after ordering the filter I realized I already had an IR filter that came with my DSI. So I thought I'd put it in the SAC and see if it made a difference. Hence the purpose of this thread. It really did make a difference in my situation. Once I get the UV/IR I will post comparison shots. The real test will come with imaging Saturn and Jupiter during their next apparitions.