Quote:
Originally Posted by RobF
Ok Dennis, just out of interest, how far left or right of the plane's course could Chris have been before the aircraft wouldn't have been reasonably centred in the pic? I wonder how many metres it would have to be?  |
Quote:
Originally Posted by hotspur
Now that Rob,is a excellent question,I have been thinking about this quite a bit. May be Dennis and ChrisM and others might like to have a graph or similar to let us know.
Cheers Chris
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Okay, I’ve approached this in 2 ways and either, or both, may be incorrect so you maths geniuses out there please let me know what you think!
Simplistic analysis from image in Photoshop CS5:
Measured distance from fuselage to “top” of Moon = 470 pixels.
Measured distance from fuselage to “bottom” of Moon = 520 pixels.
At a scale of 23.44 pixels/metre, then the airplane would skim the “top” and “bottom” of the Moon some 21 metres and 23 metres from Chris’ observatory respectively, taking into account the ground angle of 73° 46’.
Parallax calculations:
Using Parallax per the attached diagram, the answer comes out at ± 30 metres.
I don’t know what you all think, but these values seem surprisingly small?
Cheers
Dennis
PS – I have ignored the altitude of Chris’ observatory and the angle of attack of the Airplane to the Moon’s equator of approx -27°, plus other stuff I probably haven’t even thought of!
EDIT #1: Added a screen capture of updated spreadsheet with the calculations for the width of the ground track that straddles Chris’ observatory – a measly ± 30 metres!!!
EDIT #2: Updated diagram added with improved text quality and typo corrections.