utilitiesΒΆ

This submodule provides utility constants and functions for working with star data in GIANT.

Most of these utilities are focused on conversions of either units or of representations (ie a bearing to a unit vector) with the exception of applying proper motion and computing the distance between 2 bearings. For more details on what is contained refer to the following summary tables and the documentation for each constant/function.

Function

apply_proper_motion

This function adjusts the right ascension and declination of stars to a new time.

datetime_to_mjd_years

This function converts a python datetime objects to the number of SI years since the MJD Epoch of November 17, 1858.

timedelta_to_si_years

This function converts a python timedelta object to a fractional number of SI years.

Constants

DEG2RAD

This constant converts from units of degrees to units of radians through multiplication.

RAD2DEG

This constant converts from units of radians to units of degrees through multiplication.

DEG2MAS

This constant converts from units of degrees to units of milli-arc-seconds through multiplication.

MAS2DEG

This constant converts from units of milli-arc-seconds to units of degrees through multiplication.

RAD2MAS

This constant converts from units of radians to units of milli-arc-seconds through multiplication.

MAS2RAD

This constant converts from units of milli-arc-seconds to units of radians through multiplication.

PARSEC2KM

This constant converts from units of parsecs to units of kilometers through multiplication.

AVG_STAR_DIST

The average distance of stars from the UCAC4 catalog in kilometers.

AVG_STAR_DIST_SIGMA

The sigma value to use for stars with parallax that is not well known or known at all.

SI_DAYS_PER_YEAR

This constant provides the number of SI days in a SI year.

SI_SECONDS_PER_DAY

This constant provides the number of SI seconds in a SI day.

MJD_EPOCH

This constant provides the standard modified Julian date epoch, November 17, 1858, as a datetime