Which IR pass filter to get ??

[beamish]

..........with an 8" aperture ought I to get the 742nm or the 807nm Astronomik filter, I know I need one but which would you planetary imagers suggest ?

[beamish]

bumpity bump ???

[red dwalf]

i was told get any one making sure it has uv and ir filtering, i think that the baader ones, which i bought second hand look very good but you can buy other makes for about £25

[johnh]

Karlo for the 8" 742nm is best I have a larger scope and 742nm does me as the 807nm is too dim and does not seem to show more contrast with Moon/Mars/Venus or Mercury for which the IR pass filter is used. The 742 with Mars is noisy with my 350mm Newt so 807nm would be very noisy!

John.

[riklaunim]

I have 150/750 Newtonian and Pro Planet 742 nm is very good with DMK21 and that scope. Astronomik advise 742 for 5" and more, and 804 from 10" and more.

[beamish]

Many thanks chaps- I thought the 742nm would be okay but pleased I asked to get some confirmation- Much appreciated !

PS Red Dwarf, I think you might be thinking of the UV/IR block filter, the IR pass is w/length specific and helps when seeing isn't too great, but thanks for answering