What does this tool do?

It returns Julian Date, GMST and LST from UTC and longitude via computeSidereal.

How is LST related to GMST?

LST hours = wrap(GMST hours + longitude/15). At longitude 0 they match.

The value is astronomy-engine SiderealTime (mean sidereal time used as GMST).

Julian Date, GMST and LST from UTC and longitude — a developer-facing astronomy primitive

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LST = GMST + longitude/15 hours. Intended as a primitive for other celestial mechanics work. Runs locally.

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