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(meteorobs) Rich Field Refractors
Lew;
I am the one that wrote you about my 6" f/5 Jaegers refractor. I am
encountering some problems with that but what I am really writing about
is your conversation with Malcolm which has raised some questions in my
mind about use of maps with the refractor. I've had several courses in
optics including a practical one in which the image formation was
covered in details that I have long forgotten.
The image you see in looking directly through a refractor without
erecting elements or diagonal is reverted or something like that, but
not simply inverted. I think of it like looking at the back side of the
negative of your camera where looking at the front side it is inverted,
or rotated if you prefer. This necessitates special star maps. I
somehow had the impression that the diagonal might correct this even
though it is an odd number of reflections, the opposite of a reflecting
telescope. Or is it like looking in the mirror when you shave where the
man in the mirror is left handed and you are right handed, but in this
case you would be more screwed up at the telescope ||8-).
The problem I am having with my Jaegers is that the eyepiece
holder is 2.7" in diameter made to hold the 1.5" EFL wide angle Erfle
with a 65o AFV. I do have an adapter for a 1.25" eyepiece but that
would limit the field with such a diagonal. I no longer have access to
a machine shop to make any such modifications.
Also the air spacing on the primary may be screwed up. I no longer
have access to a large flat, so I am waiting for a clear night and the
time to test that and hope I can somehow separate the elements of the
objective if necessary.
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