Re: [amsat-bb] Where is EQX of sun ?

["laura halliday" <marsgal42@xxxxxxxxxxx>]

"William Leijenaar" <pe1rah@hotmail.com>

wrote:

>To do some satellite tracking by hand (yes without pc !!) I need to know at
>how many longitude the sun passes the equator from south to north.
>
>Does this angle changes every sun crossing, or is it stable ?

If you're asking about the March equinox, the position is in
the constellation Pisces, at (by definition) right ascension
0 hours 0 minutes. The location changes due to the precession
of the equinoxes; at one time it was in Aries (hence "First
Point of Aries"). In the future it will enter Aquarius, hence
that nonsensical song (am I showing my age here? :-).

The actual date and time of the equinox wobbles around a bit
due to precession and other factors, with big jumps each
leap year. Then you get to relate that to terrestrial
longitude. Do a search and you'll find information.

Laura Halliday VE7LDH     "Que les nuages soient notre
Grid: CN89lg                    pied a terre..."
ICBM: 49 16.57 N 123 0.24 W        - Hospital/Shafte

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