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Paul Hirose wrote
|
| George Huxtable wrote:
| > The Moon's angular speed
| > through the stars changes; the lunar distance target body may misalign 
with
| > the direction of the Moon's motion; and particularly, "parallactic
| > retardation" may play a big part.
|
| According to my program, the topocentric lunar distance was increasing
| 22.2" per minute of time, and the geocentric distance increasing 35.1"
| per minute. These rates are 93% and 97% (respectively) of the total
| angular velocities of the bodies.

Thank you, Paul; that's useful information.

Paul is saying that the topocentric lunar distance, the actual angle 
measured from the Earth's surface, is changing by 22.2" per minute of time. 
This is indeed  significantly less than the Moon's "nominal" speed of 30" 
per minute, but is over two-thirds of it. In which case, I remain rather 
puzzled that Frank's lunar calculator comes up with a calculated error of 
only 26' or 27', less than half of the contrived error in longitude of 1º. 
Am I misunderstanding something? Can anyone explain? Perhaps it calls for an 
understanding of the inner workings of Frank's calculator.

George.

contact George Huxtable, now at george@hux.me.uk
(switched from george@huxtable.u-net.com)
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. 


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