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Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User
harbinjer
super member
Reged: 12/17/08
Posts: 127
Loc: Southeastern Minnesota
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I hope this is the right place to ask. Can a projection adapter(for a dslr) be used a a prime focus adapter if you leave out the eyepiece?
So if I have a refractor(no diagonal)->projection adapter(no eyepiece)-> dslr, will that likely work for prime focus? Or is there something I don't understand about this? Is it just a question of reaching focus?
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zerro1
member
Reged: 08/02/09
Posts: 53
Loc: NW
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it should just be a question of reaching focus. it's more a question of whether your scope has the range of focus. my refractor doesn't. my SCT does. you may be able to focus on terestrial objects but not celestial objects. good luck
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Jerry Lodriguss
Vendor
Reged: 07/19/08
Posts: 576
Loc: Voorhees, NJ
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Yes, if you can reach focus with it... however, if it is a 1.25 inch adapter on the end that goes into the focuser, you will almost certainly get severe vignetting with it.
Jerry
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A Beginner's Guide to DSLR Astrophotography
http://www.astropix.com
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harbinjer
super member
Reged: 12/17/08
Posts: 127
Loc: Southeastern Minnesota
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Jerry, is this even with a APS-c sized sensor(Canon Rebel XS)? Would a regular 1.25" prime focus adapter work fine, or would I need a 2".
What about a 1.25" barlow(with a prime adapter)? Will that vignette the view?
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Jerry Lodriguss
Vendor
Reged: 07/19/08
Posts: 576
Loc: Voorhees, NJ
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Yes, it would vignette even with an APS-c sensor.
A 1.25 inch regular prime focus adapter will vignette also.
A 1.25 inch barlow will probably vignette also.
You really need a 2 inch adapter.
It all depends on the distance of the 1.25 inch opening to the sensor, and the type of light cone entering the camera from the scope.
Jerry
--------------------
A Beginner's Guide to DSLR Astrophotography
http://www.astropix.com
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zerro1
member
Reged: 08/02/09
Posts: 53
Loc: NW
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Hello Jerry
Is that vignette problem only a refractor issue in this instance, or would it apply accross all types of scopes?
I have only experienced it with my LX50-8" SCT and canon XS/1000D, when using a 6.3 focal reducer. My adapter is a 1.25".
Thanks
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Ptarmigan
Carpal Tunnel
Reged: 09/23/04
Posts: 2366
Loc: Arctic
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The Meade eyepiece projector one have at the end that can be unscrewed to be a prime focus adopter with a T-ring. I have a 1.25 and have no issues with vignetting.
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Ptarmigans=Cute and Cuddly
Meade Starfinder 8
Nikon 10x50
Rebel XT
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Jerry Lodriguss
Vendor
Reged: 07/19/08
Posts: 576
Loc: Voorhees, NJ
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You might get away with it at f/10... why don't you just try it?
Jerry
--------------------
A Beginner's Guide to DSLR Astrophotography
http://www.astropix.com
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