Yes Trev the 150mm f5 had CA , but to me I found its sharp views of Jupiter at about 90x made up for it , very sharp otics that one .
I had a feeling you were looking at that f11 , 4 incher . Nice scope .
I beileve it would give very good luna planetary views with minimal CA , especially if you choose your eyepieces carefully and use a prisim (Tak or Zeiss ) diagonal , Orthos will show CA quite bad ( but super sharp ! ) , Plossls will be better,
but in my opinion TelVue Radians are the best high power eyepieces made for when you want the best natural colour free views thru an achromat .
Some say they impart a yellowish ting on bright objects when using a reflector , but that's a good thing , again my opinion , I love mine in my 127mm Istar , very clean , natural views .
Good luck Trev on what you decide .
Brian.
Quote:
Originally Posted by Regulus
I laughed. It did make sense once I rearranged a few word :-)
I am looking at a 100 f11 and wondering if I will be overly disappointed with CA on bright planetary, and Lunar viewing.
I understand the fringe-killer filter is quite good and was wondering how much they effect contrast (eg Jupiter cloud bands and Saturn's rings).
I am surprised to read that a large f6.5 achro isn't badly plagued by CA and can only think the lenses must be very well made and coated.
The 150 f5 that Brian had was a demon for CA, extreme on the Moon and Jupiter/Venus etc.
If, as I have seen on some 100MM achros, the fringe is minimal then I think I will buy it since the price is good. It's just to bad that I cannot try before I buy, but that's a common problem everywhere - and worse in Tasmania.
It would still work photographically using RGB filters and Ha OIII
Thx everyone for you comments
Trevor
|