Quote:
Originally Posted by alistairsam
slightly off topic, I plan to get an OIII filter as well to use with my 8" F4 scope, but am stuck between choosing a 1.25" and 2" EP, both 68deg AFOV.
A 20mm 1.25 GSO superview EP or a 30mm 2" GSO superview. Not sure of the numbers, but the 20mm would provide reasonably better sized objects than the 30mm as the scope is only an F4 and as its 68deg, should be comfortable enough for viewing.
The 2" would be far better and you wouldn't have to shift your eye to cover the whole FOV, but then objects would be smaller.
|
Hello ---- I don't know your first name?
My 2c worth...
Go the 20mm GSO- at that f/length, it will be used a lot. Your 30mm probably won't get a lot of use (I know mine doesn't), tho still a useful addition to the kit never-the-less. The 30mm is mainly good for w/field views for finding things. So if you are going to filter anything, I'd be throwing the filter on the 1 1/4 eyepieces. I find the 14mm range also a necessary focal length which I use mostly.
Regarding an OIII filter on M42 (The Orion Neb.), in my experience from having used both the UHC and the OIII, I find the UHC does a better job with contrast and bringing out the dark structures. The OIII made it brighter (I believe that's the oxygen rich area thru the middle of the neb
)- but didn't offer the best contrast, re: structure of the wings and fish's mouth. This nebula has an awesome greeny tinge at lower powers. My next obs of, I have to see if I can hunt down some pink in it- apparently it's there!