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Location: UFOUpDatesList.Com > 2007 > Dec > Dec 7

Re: Skylab 3

From: James Smith <lunartravel.nul>
Date: Thu, 6 Dec 2007 12:48:17 -0500 (EST)
Archived: Fri, 07 Dec 2007 06:14:15 -0500
Subject: Re: Skylab 3

>From: Brad Sparks <RB47x.nul>
>To: ufoupdates.nul
>Date: Thu, 6 Dec 2007 07:48:34 EST
>Subject: Re: Skylab 3

>>From: James Smith <lunartravel.nul>
>>To: ufoupdates.nul
>>Date: Wed, 5 Dec 2007 14:31:20 -0500 (GMT-05:00)
>>Subject: Re: Skylab 3

>>>From: Bruce Maccabee <brumac.nul>
>>>To: <ufoupdates.nul>
>>>Date: Tue, 4 Dec 2007 23:32:09 -0500
>>>Subject: Re: Skylab 3

>>>>From: James Smith <lunartravel.nul>
>>>>To: ufoupdates.nul
>>>>Date: Mon, 3 Dec 2007 14:08:31 -0500 (EST)
>>>>Subject: Re: Skylab 3

>>>>Query: The second set of photos that we blew up we found
>>>>on the filmstrip, but they didn't come out; they were
>>>>underexposed. If I looked at the records correctly, they were
>>>>approximately an f/4.5 and the others were approximately a f/8.
>>>>They were also blurry so there might have been some movement
>>>>although the shutter speed was 1/500 of a second."
>>Could the 'structure' in the fourth be simply due to camera
>>jostle since no astronaut mentions it?

>If the exposure was 1/500 of a second then camera "jostle" would
>be virtually impossible, as that would mean the camera was
>jerked at a velocity of about 0.4 m/sec or about 1 ft/sec. The
>Y-shape of the 4th photo red object is not a continuous motion
>smear image. The camera motion would have to precisely retrace
>one branch of the Y-shape then move back up the other branch
>which is patently absurd.

Does f-stop truly relate to the exposure time? I remember in
Rutledge's book (Plate 9, 800mm lens, f/8 had a 1 minute
exposure) that he had time exposure images with standard f-
stops. I am a novice about photography. Is there some other
setting to keep the iris open for time lapse? Does the f-stop
affect over-under exposure?

The f-stop (f/4.5) mentioned was for the prior blurred laser
images. Of course, by my past logic it would make sense that
they keep the same f-stop but then it is possible for it to be
the f/8 (1/125 second). Seems pretty fast, but maybe slow enough
to catch a jostle, I haven't measured jostle speed before. How
much of a distance must the camera be jostled to replicate the
image using a single red dot?

For this camera, out of the about 600 frames of the 10 film
magazines, about 50 images were blurred (about 20 blurred images
occurred in the UFO sequence film magazine +the one prior),
about 10 out of focus (6 in the two film magazines), about 30
underexposed (3 in the two magazines), and 3 over exposed. So
blurred images seemed to occur more frequently for some reason
during these final two film magazines. Due to the nature of the
other blurred frames (not points of light in darkness, except
for the immediately prior blurred laser frames), the kind of
blur would be hard to see. Blur implies one axis of motion.

I know I have messed up alot of photos simply from pressing the
button on the camera without holding still enough. The blur in
my fouled up photos do not stand out as to the exact trajectory
of camera movement due to the large amount of complexity in the
image, but for a single point light source, it might be viewed.

>If the 300 mm lens was used then according to Bruce's
>measurement the image was only 2.9 milliradians or about 10
>arcminutes or about 1/3 Full Moon. That is not a prominent
>angular size, and given a 10-second cycle of brightening and
>dimming (or rotation where the full Y-shape was only seen
>briefly during the 10-second period) then there was not
>continuous visibility of the Y-shape.

If they looked through their camera to take the "structure"
image, then I assumed they could see the object with its
structure, even though it may not be visible to the naked eye.
The lens would make it visible to the photographer, as he took
his time to aim and shoot. But the photographer doesn't mention
any structure in his account. If it was spinning much faster (<1
sec/cycle?), then even looking in the camera lens would make the
structure not visible, except on film when the quick camera
speed captured the shape. But this is not the account. The other
possibility was two cycles of rotation somehow superimposed,
one, slow, which caused the general brightening and the other,
very fast, making it seem a circular blob.

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