# poliastro.core.fixed¶

Low level ra, dec, and W calculations for bodies.

REFERENCES: The values for all bodies except the Moon have been taken from: Archinal, B., Acton, C., A’Hearn, M., Conrad, A., Consolmagno, G., & Duxbury, T. et al. (2018). Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2015. Celestial Mechanics And Dynamical Astronomy, 130(3). doi: 10.1007/s10569-017-9805-5.

The values for Moon have been taken from: Archinal, B., A’Hearn, M., Bowell, E., Conrad, A., Consolmagno, G., & Courtin, R. et al. (2010). Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2009. Celestial Mechanics And Dynamical Astronomy, 109(2), 101-135. doi: 10.1007/s10569-010-9320-4.

## Module Contents¶

### Functions¶

 Calculate rotational elements for Sun. Calculate rotational elements for Mercury. Calculate rotational elements for Venus. Calculate rotational elements for Mars. Calculate rotational elements for Jupiter. Calculate rotational elements for Saturn. Calculate rotational elements for Uranus. Calculate rotational elements for Neptune. Calculate rotational elements for Moon.
poliastro.core.fixed.sun_rot_elements_at_epoch(T, d)

Calculate rotational elements for Sun.

Parameters
• T (float) – Interval from the standard epoch, in Julian centuries i.e. 36525 days.

• d (float) – Interval in days from the standard epoch.

Returns

ra, dec, W – Right ascension and declination of north pole, and angle of the prime meridian.

Return type
poliastro.core.fixed.mercury_rot_elements_at_epoch(T, d)

Calculate rotational elements for Mercury.

Parameters
• T (float) – Interval from the standard epoch, in Julian centuries.

• d (float) – Interval in days from the standard epoch.

Returns

ra, dec, W – Right ascension and declination of north pole, and angle of the prime meridian.

Return type
poliastro.core.fixed.venus_rot_elements_at_epoch(T, d)

Calculate rotational elements for Venus.

Parameters
• T (float) – Interval from the standard epoch, in Julian centuries.

• d (float) – Interval in days from the standard epoch.

Returns

ra, dec, W – Right ascension and declination of north pole, and angle of the prime meridian.

Return type
poliastro.core.fixed.mars_rot_elements_at_epoch(T, d)

Calculate rotational elements for Mars.

Parameters
• T (float) – Interval from the standard epoch, in Julian centuries

• d (float) – Interval in days from the standard epoch

Returns

ra, dec, W – Right ascension and declination of north pole, and angle of the prime meridian.

Return type
poliastro.core.fixed.jupiter_rot_elements_at_epoch(T, d)

Calculate rotational elements for Jupiter.

Parameters
• T (float) – Interval from the standard epoch, in Julian centuries

• d (float) – Interval in days from the standard epoch

Returns

ra, dec, W – Right ascension and declination of north pole, and angle of the prime meridian.

Return type
poliastro.core.fixed.saturn_rot_elements_at_epoch(T, d)

Calculate rotational elements for Saturn.

Parameters
• T (float) – Interval from the standard epoch, in Julian centuries.

• d (float) – Interval in days from the standard epoch.

Returns

ra, dec, W – Right ascension and declination of north pole, and angle of the prime meridian.

Return type
poliastro.core.fixed.uranus_rot_elements_at_epoch(T, d)

Calculate rotational elements for Uranus.

Parameters
• T (float) – Interval from the standard epoch, in Julian centuries.

• d (float) – Interval in days from the standard epoch.

Returns

ra, dec, W – Right ascension and declination of north pole, and angle of the prime meridian.

Return type
poliastro.core.fixed.neptune_rot_elements_at_epoch(T, d)

Calculate rotational elements for Neptune.

Parameters
• T (float) – Interval from the standard epoch, in Julian centuries.

• d (float) – Interval in days from the standard epoch.

Returns

ra, dec, W – Right ascension and declination of north pole, and angle of the prime meridian.

Return type
poliastro.core.fixed.moon_rot_elements_at_epoch(T, d)

Calculate rotational elements for Moon.

Parameters
• T (float) – Interval from the standard epoch, in Julian centuries.

• d (float) – Interval in days from the standard epoch.

Returns

ra, dec, W – Right ascension and declination of north pole, and angle of the prime meridian.

Return type