I recently purchased a Kendrick Baader solar filter for a 12" LX200 from Hands on Optics. It was represented as a "full aperture" but turned out to be a Off Axis type when recieved. After some thoughtI wonder if I may be better off with this than the " full aperture" I expected. Can anyone expand on the pro's and con's of each type and comment as to which may be best for the casual observer?
Off Axis Solar filter
Started by David W, 04/26/2002 02:50AM
Posted 04/26/2002 02:50AM
Opening Post
Posted 04/26/2002 04:20AM
#1
I got a 3" piece of Baader material from Draco Productions not too long ago and built an off axis filter out of it and some cardboard and duct tape for my 8" dob. I don't have a full aperture filter to compare it to but I've been happy with the results. I can usually get about 120x with a 10mm plossl with good results but the jump from that eyepiece to my 6mm at 200x is a little too much, generally at that magnification the image gets a bit hard to focus and won't really get as sharp as I'd like.
That doesn't bother me at all though because from what I've observed the most interesting views are low magnification anyway. I generally use a 25mm plossl for most of my solar viewing and rarely even bother putting the 10mm in.
I would think the only benefit of the full aperture filter would be a gain in sharpness at higher magnifications in which case I see no point. Maybe there's more to it, so I'll watch this thread to see what people who have compared the two side by side say but on something as bright as the sun I can't imagine why anything more than 3 inches of aperture would be necessary. Plus it would seem to me that the larger aperture would make low magnification viewing a bit uncomfortable because of the increased brightness.
My thoughts~
---Daniel
That doesn't bother me at all though because from what I've observed the most interesting views are low magnification anyway. I generally use a 25mm plossl for most of my solar viewing and rarely even bother putting the 10mm in.
I would think the only benefit of the full aperture filter would be a gain in sharpness at higher magnifications in which case I see no point. Maybe there's more to it, so I'll watch this thread to see what people who have compared the two side by side say but on something as bright as the sun I can't imagine why anything more than 3 inches of aperture would be necessary. Plus it would seem to me that the larger aperture would make low magnification viewing a bit uncomfortable because of the increased brightness.
My thoughts~
---Daniel
Posted 04/26/2002 05:08AM
#2
Greater aperture = better resolution. And with a full-aperture filter, you can always make an off-axis mask to put over it, best of both worlds. If you are limited to only an off-axis filter, you will not be able to take advantage of those flashes of really good seeing.
You paid for a filter that was represented to be full aperture, you should insisit on getting what you paid for.
Paul Gustafson
You paid for a filter that was represented to be full aperture, you should insisit on getting what you paid for.
Paul Gustafson
Funding Member
