hapsira.earth.util

Module Contents

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.

hapsira.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, David A.

hapsira.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