Re: Elevation of observations

Alan Pickup (
Thu, 1 Jan 1998 13:03:20 +0000

In message <>, Alphonse POUPLIER
<> writes
>" I'm surprised to see that many members give in their signature
>" their elevation even if it is less than 1000 m.
>" A typical example (unfavorable): A satellite "flying" at 350 Km.
>" The maximal difference between an elevation of zero and 1000 m
>" is 0.084 degrees for the altitude over the horizon...!

But...observers of satellite positions strive for greater accuracy than
this. For such observations to have maximum utility in analyses, the
provision of observing site coordinates (which include the altitude
above sea level) to better than 1km is justified.

>My pleasure, avec plaisir, Alphonse   URL:
>Wepion +50d25m27s 4d51m42s East. Parfois: Esparron +43d44m18s 5d58m12s
>Il existe une liste astro-satellites-informatique EN FRANCAIS.
>Pour s'inscrire, TEXTE:subscribe alphonse

To turn you argument around, why do you and others supply your longitude
and latitude to an accuracy of 1 second of arc when (taking your sig as
an example) this equates to 31m in latitude and 20m in longitude?

 Alan Pickup | COSPAR site 2707:   55d53m48.7s N   3d11m51.2s W    156m asl
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