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Eyepieces for Fast Dobs

Started by Jud, 06/13/2006 12:43PM
Posted 06/13/2006 12:43PM | Edited 06/13/2006 12:44PM Opening Post
I am wondering if it would be uesful to have a Forum entitled Eyepieces for Fast Dobs? Particularly for a newbie or a novice like me, it is sometimes very tough to wade through the myriad of comments that mix scope types and focal lengths. It is doubly confusing when the type of scope is never mentioned. As a result it undoubtedly becomes difficult for the less informed to make reasonable decisions. Only by extensively following numerous threads, have I even begun to understand how to select eyepieces. It appears that there is a large enough contingent of observers using fast dobs who could benefit from a more focussed forum. If we can have a Forum with only 29 hits, certainly a Forum on Eyepieces for Fast Dobs can be justified. Yeah, I know, confusion brings more equipment to the classifieds so we all benefit. But, I can cite many parallel examples of that kind of marketing that we all have complained about.

I Yam What I Yam!
Posted 06/13/2006 05:12PM #1
Hi Jud,
Well maybe, but perhaps that would be a good subject line. Herb would have to decide on that one I think.
It would be very useful if the discussion posted were to be given a subject heading that would help with searches.
I also have been advocating that all should post what the scope was and what they were observing when making reviews or statements about EPs.
There would also be the possibility of that being a subject for the Dobsonian forum, but I think this forum is probably the proper place at this time.
There are so many things that influence the performance or perceived performance of an EP.
Field curvature can be canceled by a scope that has the opposite curvature and the EP and scope will perform to a higher degree.
Focal length will effect the EP in many ways so that an EP that performs well at f/10 is not too good at f/5.
Weight and size can also be a factor for some scopes.
Eye relief can be a big deal for some, and make an EP seem to perform better because it is more comfortable.
Some EPs look good at night but do not look good during the day. Chromatic aberration or Rectilinear distortion may show very badly under daytime conditions, but not so much at night.
So when, where and in what are real factors that need to be mentioned with talking performance .

[SIZE="Large"][/SIZE][COLOR="Blue"][/COLOR] Floyd Blue grin
Amateur Imager
Posted 06/13/2006 05:53PM #2
I'm with Floyd and Jon.
The most valuble discussions alway include focal ratio of the scope involved. If an ep review does not, then it is of little or no use to a fast newt owner, and really should be disregarded as a guide for ep's. That's kinda the hard truth of it. I too have waded through huge threads of so called wonder ep's, only to have the reviewer finally days later actually share that the scope involved was f6 or slower. If the review doesn't specify the f ratio and one has a fast scope, then skip it.