Re: sufficient twlight definition/approximation?

Bjoern Gimle (
Tue, 7 Jul 1998 07:25:53 +0200 wrote

>nice to have a definition that took into account the expected satellite
>magnitude (if available).  Something like for a mag Y satellite, the sun
>must be at least X degrees below the horizon where Y is estimated the usual
>ways and X is computed from Y in some way.
There were two programs in a recent Sky&Telescope, now available on their
website, to compute the limit magnitude at a any specific point of time,
and the CCD limit magnitude, give data like date, time, observer lat/lon and
altitude, Sun and Moon position, object position (and the angles between
them!), atmospheric condition ... Unfortunately NONE of these values is
computed - they are program constants, or runtime input. It would be nice
to have the routine integrated into a magnitude-edtimating program like
QuickSat (though it might slow it down noticably) or SkyMap.

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