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Location: UFOUpDatesList.Com > 2005 > May > May 20

Re: Google Maps Captures UFO? - Ledger

From: Don Ledger <dledger.nul>
Date: Fri, 20 May 2005 10:23:17 -0300
Fwd Date: Fri, 20 May 2005 11:59:45 -0400
Subject: Re: Google Maps Captures UFO? - Ledger


>From: Bob Shell <bob.nul>
>To: ufoupdates.nul
>Date: Thu, 19 May 2005 10:24:17 -0400
>Subject: Re: Google Maps Captures UFO?

>>From: Don Ledger <dledger.nul>
>>To: ufoupdates.nul
>>Date: Wed, 18 May 2005 13:11:59 -0300
>>Subject: Re: Google Maps Captures UFO?

>>Usually crosshairs or right angled marks
>>- reticles or graticules, Latin or Fr. - are scribed right
>>into a thin glass between lenses. Note Lunar photos, etc.

>The crosshairs seen on the lunar photos and others are marked
>on a flat glass plate, called a reseau plate, which is right in
>front of the film and pressed against the film by spring
>pressure during the exposure. Reseau plates are used on metric
>cameras (mapping cameras) and are not reticles or graticules.

What are they called then?

>Reseau plates are never between lenses! If they were, there
>would be no focused image of them on the film.

>A digital mapping camera would have the + marks on a glass
>plate in front of (and in contact with) the digital sensor
>array.  This would produce sharp + marks, just as on a film
>camera.

Makes sense to me, now that you mention it. The astronauts on
the Moon were using Hasselblads with this feature.

>Personally, I think we're seeing some sort of high-altitude
>balloon, or balloons. The soft focus is because the balloon is
>much closer to the camera and outside of its field of sharp
>focus. We'd need to know the focal length of the lens, lens
>aperture, and sensor size to compute what the depth of field
>would be.

That's as I was suggesting with perhaps parallex accounting for
mutiplicity.


Don Ledger





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