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Old 05-05-2014, 10:05 PM
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Andy01 (Andy)
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Canon 40da FOV

Hi Folks,

I've loaned a modded/cooled Canon 40d SLR and am looking to plan some AP targets.
Can anyone help with the FOV of the Canon 40d when equipped with an 85mm lens?
Also the FOV when it's attached to a 770mm refractor with a .85 Flattener/reducer?

Thanks in advance

Cheers
Andy
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Old 06-05-2014, 06:03 AM
Dennis
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Hi Andy

Have a look at this site.

http://www.howardedin.com/articles/fov.html

Select your camera (40D) and enter your lens focal length and it provides the FOV.

For your telescope, the focal length will be 770 x 0.85 = 655.

Another very useful resource is:
http://www.wilmslowastro.com/software/formulae.htm

Cheers

Dennis
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Old 06-05-2014, 10:07 PM
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Andy01 (Andy)
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Quote:
Originally Posted by Dennis View Post
Hi Andy

Have a look at this site.

http://www.howardedin.com/articles/fov.html

Select your camera (40D) and enter your lens focal length and it provides the FOV.

For your telescope, the focal length will be 770 x 0.85 = 655.

Another very useful resource is:
http://www.wilmslowastro.com/software/formulae.htm

Cheers

Dennis
Awesome, that's most helpful!
Thanks heaps Dennis

Cheers
Andy
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Old 07-05-2014, 01:09 PM
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mithrandir (Andrew)
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Another excellent resource is CCDCalc. You do need to add your gear to the database.
Canon 40Da chip - 5.7um pixels and 3888x2592 array size.
Canon 85mm f1.8 USM - 47mm aperture and f1.8.
Those values give FOV 899.4x599.6 arcmin.

You didn't list an f ratio for the refractor. 770mm sounds like a 110mm f7 (eg William Optics Fluoro Star 110).
That gives FOV 98.8x65.9 arcmin without the flattener and 116.3x77.5 arcmin with the 0.85
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Old 07-05-2014, 04:03 PM
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Andy01 (Andy)
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You didn't list an f ratio for the refractor. 770mm sounds like a 110mm f7 (eg William Optics Fluoro Star 110).
That gives FOV 98.8x65.9 arcmin without the flattener and 116.3x77.5 arcmin with the 0.85[/QUOTE]

Oops! My bad, it is a William Optics FLT 110 f7.0 the reducer is actually .8 too.
Thx for the tip
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