|
Hi Stefan
Depends a bit as to how much chromatic aberration is present in the refractor. For a fast achromat a Baader contrast booster will help with chromatic aberration and light pollution (better contrast with viewing). A refractor with minimal CA the semi apo would be good and again helps with light pollution (with little perceptible change in colour tone). For visual in dark skies the Baader 495 is hard to beat but no real effect on light pollution here and bright stars look a little yellow.
Another option is the Baader UHCS which is a very good light pollution filter and reduces blue flinging pretty well. If you are mainly using for imaging this may be a good option from the burbs. There are other good LP filters that are very similar - check the transmission curves.
Cheap and cheerful for general viewing a Wratten 11works very well with pretty good transmission and is much overlooked. Not as much transmission as a Wratten 8 but much better blue and red fringing correction. For a smaller refractor the Wratten 8 may have the edge due to better transmission.
Regards
David
|