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Raven911
Carpal Tunnel
Reged: 03/12/05
Posts: 1870
Loc: by Cloudcroft, NM
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I just want to get a consensus of what most folks use in their imaging train with an aftermarket crayford on thier sct. Do most people here mount the reducer directly on the back of the sct or do the mount the crayford on the sct and then the focal reducer?
I am using a C9.25 and have been thinking of getting an auxilliary crayford for it.
I am currently using the following imaging train on my sct:
C9.25/focal reducer/flip mirror/filter wheel/CCD
Does anyone else use anything different? If I add a crayford in there before the reducer, will it affect anything?
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http://smg.photobucket.com/albums/v287/Raven911/Astrophotos/
http://www.eye-of-the-raven.blogspot.com/
My list of second-hand and home-made stuff:
Celestron SC6
Celestron C9.25
100mm F6/76mm F4.5/80mm F5/SV NHII 80mm F6 Achros
SBIG ST7/Canon 300D/DSI Pro Mono/Starshoot DSCI
8 inch F7 Newt on Edmund EQ
8 inch F4.5 Project Astrograph
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geokolb
member
Reged: 07/10/07
Posts: 16
Loc: Phoenix, AZ
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Paul,
The answer is... it depends. The recommended spacing between the FR and the CCD is 105mm. If you go longer, the compression will be more and vice-versa. The problem is vignetting will get worse the longer you go. Add up the distance between the FR and your chip to determine if the FR should go before the crayford or after it. See this reference to FR compression at http://www.skyandtelescope.com/howto/astrophotography/3304356.html?page=3&c=y
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Raven911
Carpal Tunnel
Reged: 03/12/05
Posts: 1870
Loc: by Cloudcroft, NM
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I should have clarified it a bit. I am pretty well versed with the .63 reducer, but recently got a .33 reducer.
I am trying to work out a way to get less distance between the ccd chip and the reducer, while still being able to keep an option open for a crayford focuser, or maybe a flip mirror in front of the reducer.
Has anyone ever done anything like this?
--------------------
http://smg.photobucket.com/albums/v287/Raven911/Astrophotos/
http://www.eye-of-the-raven.blogspot.com/
My list of second-hand and home-made stuff:
Celestron SC6
Celestron C9.25
100mm F6/76mm F4.5/80mm F5/SV NHII 80mm F6 Achros
SBIG ST7/Canon 300D/DSI Pro Mono/Starshoot DSCI
8 inch F7 Newt on Edmund EQ
8 inch F4.5 Project Astrograph
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phanf4
super member
Reged: 07/31/07
Posts: 110
Loc: Over there in Chattanooga
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One option to consider is buying a focuser made to hold the FR which may get you dead on with the distance to CCD.
See link below.
http://www.focuser.com/cgi-bin/dman.cgi?page=productdetail&plugin=dstore.cgi&product=CS
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Tom,
CGE
1984 C8 'Orange' OTA remounted
Stellarvue 80mm
EPs and Powermate
Stuff and ...Stuff
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