|
You need to get one of
the following:
(1) A Rochi grating / True Knife edge camera focuser
from Stellar Technologies,
(2) Construct one on your own: Make an 8" mask
out of cardboard (or use your dusk cover), cut two round holes in it, about 1.5"
in diameter, space them about two inches apart from the center, adjacent to each
other, tape onto corrector plaste end, when you look through your view
finder you will see two circles, focus until you see one circle. See
complete instruction on mapug.com
3 Create a "knife edge" for inside your
camera
In addition to the above, you can replace your
camera's focusing screen with a bright screen for this purpose, and
remove the camera's pentaprism and replace with a lupe
that will allow creater magnification of the film plane.
*****************************************
Ray Kilburn
Culpeper,
VA
USA
----- Original Message -----
Sent: Monday, September 03, 2001 12:24
PM
Subject: [APML] Lunar Photography
I have just experienced one of the more
frustrating lunar photography sessions of my short life and have a couple of
questions about the whole experience.
I have been using an 8" Meade
LX-200 and a Canon ELAN II (35mm SLR) doing prime focus (camera mounted
directly to the telescope with out an eye peice) and am finaly starting to get
some good results (for your viewing pleasure some of the more recent shots can
be found at http://www.manetheren.net/night). Focusing was a little off at first, and then I had some
issues with camera shake (the mirror wasn't tripping up prior to shooting) but
finaly worked those out.
So I figure I'm ready to try some eyepeice
projection. I throw in a 26mm super plossl (f/28.4), and right off the
bat I notice I can't find that "sweet spot" in the focus where everything is
crystal clear. As my camera's meter is fairly sensitive, I bracket some
of these shots on focus instead of shutter speed.
Then I decide to go for the gusto and throw in
a teleview 4.8mm Nagler (f/198.5). I couldn't even come close to getting
things in focus. Same results with my 9.7mm Super Plossl (f/94.3).
Everything is just a fuzzy gray and brown blur. I tried extending my
tele-extender all the way out and all the way back in. Didn't make a
diffrence.
I guess what I'm realy wondering is if those
focal ratios (and attendant maginifcations) are simply beyond the ability of
my scope and camera to handle.
Thanks,
Scott
"God does not play dice with the universe; He
plays an ineffible game of his own devising, which might be compared, from the
perspective of any of the other players, to being involved in an obscure and
complex version of poker in a pitch dark room, with blank cards, for infinite
stakes, with a dealer who will not tell you the rules, and smiles all the
time." -- Gaiman and Pratchett
|