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In message 5399, I had written-
|
| >it seems madness to measure hour-angles as positive Westwards, and
| >longitudes as positive Eastwards. Can anyone really justify it?


and Herbert Prinz has responded-

| The fact that now we all measure longitudes the same way is probably the
| best possible justification. Speculating about the philosophical reason
| is likely to be counter productive: It may weaken the consensus. Someone
| might come up with the really bad idea to change the convention again in
| the interest of "better science".

Well, I wasn't really "speculating about the philosophy", just pointing out
that when an object is on the observers meridian, his longitude, on the
East-is-positive convention, is equal and opposite to its GHA, whereas in
the other convention, they are the same. Which is more logical?

But do we all "measure longitudes the same way", as Herbert implies? Meeus
doesn't. Is there another text in which the author is brave enough to stick
his neck out and state that "the positive direction of increasing longitude
is here taken to be Easterly (or Westerly, as the case may be) from
Greenwich". Generally, the question is ducked, in texts and in programs, by
continuing to use an E or W label, instead of the simplicity of a sign.
Clearly, Herbert presumes that some sort of consensus exists. What does he
base that on?

George.

contact George Huxtable at 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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