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Re: FS on 24mm Widefield

Started by jonisaacs, 05/17/2006 03:32PM
Posted 05/17/2006 03:32PM | Edited 05/17/2006 03:34PM Opening Post
Does anyone have the fieldstop diameter on the TV 24mm Widefield? I went to the "Ask Al" page at Televue and found some stat's on this NLA eyepiece but not the fieldstop.
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I have a 24mm Widefield and have measured the field stop reasonably carefully. I believe the number I measured was 24.8mm. I do know that what I measured correspond to an "effective AFoV of between 59 and 60 degrees.

The formula I used was

Effective AFoV= 57.3 x (Field stop/focal length)

I have 3 Widefields, the 15mm, the 24mm and the 32mm. They all seem to have effective AFoV's of between 59 and 60 degrees.

I should add that mine has the smooth sided barrel with the rubber eye shield.



jon
Posted 05/17/2006 11:52PM | Edited 05/17/2006 11:54PM #1
Tele Vue used to publish those figures on their web site up to a few years ago. Now I believe they only publish them on eyepiece models that are still in production.

Anyway, while I don't remember what the exact figure for the 24mm Wide Field was, I do remember that it was a little smaller than the 25mm field stop on the 22mm Panoptic and that in turn would correspond to a AFOV of 59.? degrees. So your measurement and AFOV estimate are either correct or very close to being correct.
Posted 05/18/2006 09:50AM #2
Jon
I apparently have a new model of the 24mm Widefield. The other day I marked out 320 feet and affixed a steel tape to a vertical board. At that distance my field of view was 65 inches which I translated into 59 minutes actual field of view. I was using a 12" Hardin dob.

I Yam What I Yam!