Re: [ATM] Foucault test with Alaris webcam

["Nils Olof Carlin" <nilsolof.carlin@telia.com>]

Gilbert Gagne wrote:

> I'm using an Alaris "Weecam" mounted behind the KE to put an image of my
> 12" f/5.6 mirror into my laptop computer. I've removed the original lens
> and mounted a transfer lens about 0.5" ahead of the camera focal plane
> which generates an image to cover about 1/4 of the display area when
> everything is in focus. The 3/4" diam transfer lens is about 1/8" behind
> the KE. The saved image is 262K bytes but after cropping is only 15K
> bytes with not enough resolution. What kind of transfer lens do I need
> to produce a larger image?

One with about 4 times the focal length of what you have right now -
whatever that is.

Your mirror covers about 1/ (2*5.6), so the f.l should be no more than 11.2
times the width of the camera chip (you can crop the top and bottom of the
image).

Nils Olof

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