Hi Shea,
> Recently, I've found something wrong in Heavens Above's prediction
> on Iridium Flares. ... Most of them are right, but the Alt. is
> wrong. The observation is that Alt. is nearly 90° [versus 60°
> observed]. The error is roughly 30°, so great!
You may be surprised at just how high in the sky the zenith
really is -- it is not a comfortable direction to be looking
while standing, and consequently most beginning observers
overestimate all elevation angles -- with increasing errors
as the angle increases. Here is a typical altitude angle
conversion table I use for "translating" beginners' reported
altitude angles:
Reported Actual
Angle Angle
-------- ------
10 7
15 10
30 20
45 30
60 45
80 60
90 70
Try testing yourself with some bright stars that are well above
the horizon -- guess their altitude angles and then use one
of the many planetarium programs out there to see how close
you were. You may be surprised by the results.
Best wishes,
Rob
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This archive was generated by hypermail 2b29 : Wed Jul 31 2002 - 21:20:56 EDT