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To answer several queries, the calculation I meant to suggest might go
something like this ==>
Notation:
V = speed of moon in its orbit
v = speed of person walking on earth
D = moon-lens distance
d = person-lens distance
f = camera lens focal length
U = speed of moon image across film
u = speed of image of walking person across film
Optics:
U = (f/D)V
u = (f/d)v
==> u/U = (D/d)(v/V)
Data:
D = 1,246,720,000
d = 6890 ft
V = 3356 ft/sec
v = 2 ft/sec
Result:
u/U = 108
ie., The walking person's image should move across the film about 108 times
as fast as the moon's image moves across the film.
Please improve, and correct any boo-boos - and do it in metric units ; )
-----Original Message----- From: Bob Sciamanda
Sent: Saturday, March 01, 2014 11:24 AM
To: PHYS-L
Subject: [Phys-L] Trick photography?
If you’ve never seen a tele-video of a distant terrestrial scene silhouetted
by a rising moon, look at==>
http://vimeo.com/58385453.
The casual observer often complains that this must be a manipulated
photoshop type trick.
It is an interesting exercise for students to investigate this by
calculating, and comparing, the speeds of the terrestrial and lunar images
across the camera film/digital sensor.
More than sufficient data is available from the video clip, its commentary,
and known lunar data.
Bob Sciamanda
Physics, Edinboro Univ of PA (Em)
treborsci@verizon.net
http://sciamanda.com
_______________________________________________
Forum for Physics Educators
Phys-l@phys-l.org
http://www.phys-l.org/mailman/listinfo/phys-l
Bob Sciamanda
Physics, Edinboro Univ of PA (Em)
treborsci@verizon.net
http://sciamanda.com
_______________________________________________
Forum for Physics Educators
Phys-l@phys-l.org
http://www.phys-l.org/mailman/listinfo/phys-l