boinor.earth.util¶

utility functions in module util of sub-package earth

Functions¶

`raan_from_ltan`(epoch[, ltan])	RAAN angle from LTAN for SSO around the earth.
`get_local_sidereal_time`(lon, time)	Gets the local sideral time from input location.

Module Contents¶

boinor.earth.util.raan_from_ltan(epoch, ltan=12.0)¶

RAAN angle from LTAN for SSO around the earth.

Parameters:

epoch (Time) – Value of time to calculate the RAAN for
ltan (Quantity) – Decimal hour between 0 and 24

Returns:

RAAN – Right ascension of the ascending node angle in GCRS

Return type:

Quantity

Notes

Calculations of the sun mean longitude and equation of time follow “Fundamentals of Astrodynamics and Applications” Fourth edition by Vallado [Val13].

boinor.earth.util.get_local_sidereal_time(lon, time)¶

Gets the local sideral time from input location.

Parameters:

lon (astropy.units.Quantity) – East longitude of a point on a body.
time (astropy.time.Time) – Time at which to calculate the local sidereal time.

Returns:

theta – Local Sidereal Time (LST).

Return type:

astropy.units.Quantity