histastro.moon module

Moon functions for HistAstro.

histastro.moon.compute_lbr(jde, lrTerms, bTerms, debug=False)[source]

Compute the geocentric ecliptic coordinates of the Moon for the equinox of date for the given JDE.

Parameters:
  • jde (float) – Julian Day in dynamical time, i.e., corrected for Delta T (days).

  • lrTerms (float) – Numpy array with ELP82 periodic terms for longitude and distance.

  • bTerms (float) – Numpy array with ELP82 periodic terms for latitude.

  • debug (bool) – Produce debug output. Optional, default value = False.

Returns:

Tuple containing (lon, lat, dist, diam):

  • lon (float): Geocentric ecliptic longitude of the Moon (rad).

  • lat (float): Geocentric ecliptic longitude of the Moon (rad).

  • dist (float): Geocentric distance of the Moon (km).

  • diam (float): Geocentric apparent diameter of the Moon (rad).

Return type:

tuple (float,float,float,float)

Notes

  • A reduced version of the ELP82 theory is used.

  • The necessary ELP82 terms can be read from file using the function readData().

References

histastro.moon.readData(inFile='data/moonposMeeus.csv')[source]

Return the periodic terms for the ELP82B theory from moonposMeeus.csv.

  • Two arrays aand return them in two arrays: one for longitude and distance, and one for latitude.

Parameters:
  • inFile (str) – Name of the input file, including (relative or absolute) path. Optional, default

  • value = ‘data/moonposMeeus.csv’.

Returns:

Tuple containing (lrTerms, bTerms):

  • lrTerms (float): Numpy array containing six columns with periodic terms for longitude and distance. The first four columns contain arguments for both variables, the last two the coefficients for longitude and distance:

    • 1 (int): Multiplication factor for the mean elongation of the Moon.

    • 2 (int): Multiplication factor for the mean anomaly of the Sun.

    • 3 (int): Multiplication factor for the mean anomaly of the Moon.

    • 4 (int): Multiplication factor for the Moon’s argument of latitude.

    • 5 Coefficient of the sine of the argument, for the longitude (rad).

    • 6 Coefficient of the cosine of the argument, for the distance (km).

  • bTerms (float): Numpy array containing five columns periodic terms for latitude. The first four columns contain arguments, the last contains the coefficients for latitude:

    • 1 (int): Multiplication factor for the mean elongation of the Moon.

    • 2 (int): Multiplication factor for the mean anomaly of the Sun.

    • 3 (int): Multiplication factor for the mean anomaly of the Moon.

    • 4 (int): Multiplication factor for the Moon’s argument of latitude.

    • 5 Coefficient of the sine of the argument, for the latitude (rad).

Return type:

tuple (float,float)

References