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AZKick
super member
Reged: 02/25/08
Posts: 129
Loc: Phoenix, AZ
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Hi all, Being totally new to pictures with a telescope, I dont know if there is more (telephoto? zoom?) I can get out of what I have. I have the Meade ETX-80 and a Canon XTi. I glued the dust cover from the back of the scope to a body dust cover from the camera, drilled out the center, and it seams to work fine. I guess I made a T-mount adapter. My question is, if I made that adapter longer, moving the camera away from the front lens of the scope, do I get a bigger image in the frame? I don't plan on changing my setup just yet, more just trying to understand how this works.
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AZKick
super member
Reged: 02/25/08
Posts: 129
Loc: Phoenix, AZ
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Pic of the moon with this setup
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john D
All you have to do is ask!!
Reged: 08/05/07
Posts: 4966
Loc: Midlothian, VA
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thats a nice shot! cool how you got some stars in the shot with the moon! 
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Meade ETX-125
Meade LXD55 mount
Philips SPC900NC webcam
Seymour Solar filter
Backyard Observatory
 -Midlothian VA
--Land Of The Free Because Of The Brave--
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NeoDinian
Experienced Postmaster
Reged: 10/05/05
Posts: 12070
Loc: Rockford Illinois
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Moving the camera back further with Prime focus (What you have set up here) will NOT make the image bigger. It will only make you play with the focus more to reach focus...
Nice little Mod you did to get them to mate.. 
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Neo... (Jeff)
-=-=-=-=-=-=-
10" LX200-GPS/SMT UHTC "Draco"
 Rockford, Il.
NeoDinian's Eye on the Sky!
Coming soon:
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Charlie Hein
Postmaster
Reged: 11/02/03
Posts: 6579
Loc: 26.06.08N, +80.23.08W
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Hey, that's a really ingenious adaptation there...
Quote:
My question is, if I made that adapter longer, moving the camera away from the front lens of the scope, do I get a bigger image in the frame? I don't plan on changing my setup just yet, more just trying to understand how this works.
...to answer your question, you could use a barlow to enlarge the image on your camera like so:
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Weston CSC:
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AZKick
super member
Reged: 02/25/08
Posts: 129
Loc: Phoenix, AZ
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Thank you all for the coments. So I understand with my setup, prime focus is the lens striaght to the film/ccd without anything in between. And that is the reason I can only get that image size. The front lens has a set focal point/f stop so moving the camera back say 1 inch, I would have to move the lens back that same 1 inch to focus and get the same field of view. Understood (I think) Now the barlow, I remember 25 years ago useing a sears type refractor. If I put that barlow tube just bearly in the focuser tube, and put the eyepiece just bearly in the barlow, that would increase the image alot. But the barlow, I prosume, is acting like a lens group there.
Lots more question to follow, And thank you for the help
Scott
Edited by AZKick (04/14/08 12:44 AM)
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Charlie Hein
Postmaster
Reged: 11/02/03
Posts: 6579
Loc: 26.06.08N, +80.23.08W
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Quote:
I remember 25 years ago useing a sears type refractor. If I put that barlow tube just bearly in the focuser tube, and put the eyepiece just bearly in the barlow, that would increase the image alot. But the barlow, I prosume, is acting like a lens group there.
You've got it - you need the second lens(es) in order to make that happen.
Charlie
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Weston CSC:
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smasraum
sage
Reged: 01/13/08
Posts: 492
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A barlow is basically the astro equivalent of a 2x teleconverter in the photo world. It's a magnifying glass for the image that the front lens creates.
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Steve
Houston (Friendswood), TX
 Space Center Houston
8" Zhumell Dob - Woo Hoo!!
Celestron C102 f/5 - Thanks Tim!
21mm, 13mm Hyperion
2.5x TV Powermate
Canon Rebel XT
Nikon 7x35
Bushnell 10x50
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WarrenS
sage
Reged: 03/04/08
Posts: 324
Loc: Hudson Valley New York
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You were creative with your homemade adapter but I would not trust it to hold forever. I've glued plastic camera bayonet caps together in the past for other purposes and they can come apart. You don't want your camera to come crashing down to the ground one of these days. Buy a metal camera adapter with T mount. A heck of a lot less expensive than a DSLR.
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Warren
Astro-Tech 127EDT
Celestron Onyx 80ED
C8 (circa 1983 Orange Tube)
Atlas EQ-G
Canon 135mm F2.8
Canon 40D, Astronomik CLS clip filter
Leica, Minolta binos
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