2" eyepieces

Hi

I am just looking into the possibility of going into 2" eyepieces. After a bit of research I found out that there is a 1.25" baffel behind the backplate of my scope which limits the possible size of an eyepiece.

Basically the field stop of the eyepiece needs to be between 30 and 34 cm. If it is less then then 30 I am not making the most use of the available FOV and if it is more then not all of the eyepiece will be illuminated thus there will be vinietting (and I will be wasting money unless I decide to get a bigger scope later on).

I have had a look around and I have discovered that the field stop of an eyepiece is not something that is always readily advertised. Does anyone here know a reliable place to find out the field stop of a selection of 2" eyepieces that is upto date with those eyepieces currently available. Or is the vinietting something that you tend to live with?

Ta
db

Personally I didn't bother with 2" eyepieces until I had a scope with a 2" focuser. I'm not completely au fait with the geometry but looking at the three I have (30, 40 and 50mm) I think that you would get vignetting on all of them in which case you may be better off saving that money for your next scope upgrade.

Remember that it's only in longer focal lengths (typically longer than 26-28mm) that you can take advantage of a 2" design. As a general rule 2" barrels on shorter focal length eyepieces just make them more expensive.

Dave,
do you think with an 8" reflector scope you'd get much benefit from a 2" eyepiece? That would be my question I'd ask before buying. I mean, the larger the scope, the better the FOV with 2" EP's of course, but where does one draw the line?

Seanie.

I have used 2" Hyperions on my 8" sct. Even with a 1.25" diagonal the difference in FOV is very noticable. I can find DSOs with a 21mm eyepiece and a telrad quite easily-I could never do this with a 20mm plossl.
Definitely worth it with 8" of aperture.

So you reckon even a 1.25 inch Hyperions with AFOV of 68 deg c beats a 20 mmPlossel in a 8 inch SCT. What about say 25 or 32 mm. As you can see I am also looking for eyepieces (for a C9.25).

Regards Donal Mc

Comparable to a standard budget 1.25" 40mm plossl I reckon (not wide angle though) in terms of FOV at the eyepiece. I dont have a 32mm so I can't compare.