sorcha_addons.lightcurve.ellipsoidal.ellipsoidal_lightcurve
Attributes
Classes
Produces a lightcurve from a spinning ellipsoid. |
Functions
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Compute the cosine of the aspect angle |
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Compute the rotational phase |
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Compute the subobserver longitude (radian) |
Module Contents
- cos_aspect_angle(ra, dec, ra0, dec0)[source]
Compute the cosine of the aspect angle
This angle is computed from the coordinates of the target and the coordinates of its pole. See Eq 12.4 “Introduction to Ephemerides and Astronomical Phenomena”, IMCCE
- Parameters:
ra (float) – Right ascension of the target in radians.
dec (float) – Declination of the target in radians.
ra0 (float) – Right ascension of the pole in radians.
dec0 (float) – Declination of the pole in radians.
- Returns:
float
- Return type:
The cosine of the aspect angle
- rotation_phase(t, W0, W1, t0)[source]
Compute the rotational phase
This angle is computed from the location of the prime meridian at at reference epoch (W0, t0), and an angular velocity (W1) See Eq 12.1 “Introduction to Ephemerides and Astronomical Phenomena”, IMCCE
- Parameters:
t (float) – Time (JD)
W0 (float) – Location of the prime meridian at reference epoch (radian)
W1 (float) – Angular velocity of the target in radians/day.
t0 (float) – Reference epoch (JD)
- Returns:
float
- Return type:
The rotational phase W (radian)
- subobserver_longitude(ra, dec, ra0, dec0, W)[source]
Compute the subobserver longitude (radian)
This angle is computed from the coordinates of the target, the coordinates of its pole, and its rotation phase See Eq 12.4 “Introduction to Ephemerides and Astronomical Phenomena”, IMCCE
- Parameters:
ra (float) – Right ascension of the target in radians.
dec (float) – Declination of the target in radians.
ra0 (float) – Right ascension of the pole in radians.
dec0 (float) – Declination of the pole in radians.
W (float) – Rotation phase of the target in radians.
- Returns:
float
- Return type:
The subobserver longitude in radians.
- class EllipsoidalLightCurve(required_column_names: List[str] = ['fieldMJD_TAI', 'Range_LTC_km', 'RA_deg', 'Dec_deg', 'Period', 'Time0', 'phi0', 'RA0', 'Dec0', 'a/b', 'a/c'])[source]
Bases:
sorcha.lightcurves.base_lightcurve.AbstractLightCurveProduces a lightcurve from a spinning ellipsoid. The observation dataframe provided to the
computemethod should have the following columns:FieldMJD_TAI- time of observation [MJD].Range_LTC_km- Distance to target at time of observation [km].RA- SSO right ascension [deg].Dec- SSO declination [deg].Period- Sidereal rotation period [days].Time0- Reference time for the light curve [days].phi0- Reference rotational phase for the light curve [radians].RA0- SSO spin-axis right ascension [radians].Dec0- SSO spin-axis declination [radians].a/b- SSO ratio of equatorial diameters [unitless].a/c- SSO ratio of longest equatorial to polar diameters [unitless].