Re: eyepiece projection
From: Ioannis (morpheus_at_olympus.mons)
Date: 09/03/04
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Date: Sat, 04 Sep 2004 00:35:49 +0300
miso wrote:
> Dumb question perhaps, but when you do eyepiece projection
> photography, can you focus by viewing at the eyepiece then mount the
> rest of the hardware to take the photograph? I just focus at the
> camera, but it seems that once the telescope is focused, the distance
> between the eyepiece and the film plane is just altering
> magnification. My gut feeling is no, because when you view at the
> eyepiece, you are also compensating for your eyesight.
If you focus your scope to infinity, ALSO assuming you have 20/20
eyesight (for the focusing eye), then you'd get enough slack to be able
to focus your camera AT the EP, without changing focus.
In this case, moving the camera away from the EP, doesn't change the
magnification, cause rays exiting the EP are parallel. This is not true
as you say, if you focus your scope for a myopic/hypermetropic eye, or
for closer than infinity. Then, you'd lose focus if you move the camera
away from the EP, since the rays between EP and camera lens won't be
parallel.
-- I. N. Galidakis http://users.forthnet.gr/ath/jgal/ ------------------------------------------ Eventually, _everything_ is understandable
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