Any old will do for public viewing
but if you want to eekk out every last photon you can't go past an AstronomiK brand. I did an exhaustive test with Graham Longs UHC Lumi and the Astronomik beat it hands down! I think Bintel are agents. When you get the 2" variety I'll have to have ( as Ron says) a shooffty???
Cheers Zub