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Subject: Lunars and the Astra IIIb
From: Eric Haberfellner (ehaberfe@XXX.XXX)
Date: Sat Dec 15 2001 - 19:37:01 EST
I have acquired a copy of Bruce Stark's "Tables for Clearing the Lunar
Distance and Finding G.M.T. by Sextant Observation" and am planning to try
this ancient and noble art some time in the new year.
Is the Astra IIIB a reasonable instrument to attempt this with? In the
preface, Mr. Stark mentions that "0.1' of error in the distance causes about
twelve seconds of error in Greenwich time". Now, I do not know of a sextant
with a guaranteed accuracy of 0.1' (6"). The best that I know of is the
Cassens and Plath with a guaranteed accuracy of +/- 9" (0.15'). The Astra
IIIb has a stated accuracy of +/- 20" (.33'). Does this mean that it is
reasonable to attempt to determine GMT to an accuracy of about 50 seconds
with an Astra IIIb?
I would also be interested in hearing from others who have tried using Mr.
Stark's tables.
Eric Haberfellner
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