mirror of
https://github.com/cosinekitty/astronomy.git
synced 2026-05-19 14:27:52 -04:00
Python: rotations for ECT/EQD.
This commit is contained in:
Don Cross
@@ -141,10 +141,10 @@ It also allows converting from a vector to spherical (angular) coordinates and b
|
||||
within a given orientation. Note the 3-letter codes for each of the orientation systems;
|
||||
these are used in function and type names.
|
||||
|
||||
- **EQJ = Equatorial J2000**: Uses the Earth's equator on January 1, 2000, at noon UTC.
|
||||
- **EQJ = J2000 Mean Equator**: Uses the Earth's equator on January 1, 2000, at noon UTC.
|
||||
- **EQD = Equator of Date**: Uses the Earth's equator on a given date and time, adjusted for precession and nutation.
|
||||
- **ECT = True Ecliptic of Date**: Uses the true orbital plane and equator of the Earth on the given date.
|
||||
- **ECL = Mean J2000 Ecliptic**: Uses the plane of the Earth's orbit around the Sun in the year 2000. The x-axis is referenced against the J2000 mean equinox.
|
||||
- **ECL = J2000 Mean Ecliptic**: Uses the plane of the Earth's orbit around the Sun in the year 2000. The x-axis is referenced against the J2000 mean equinox.
|
||||
- **HOR = Horizontal**: Uses the viewpoint of an observer at a specific location on the Earth at a given date and time.
|
||||
- **GAL = Galactic**: Based on the IAU 1958 definition of galactic coordinates.
|
||||
|
||||
@@ -160,20 +160,22 @@ these are used in function and type names.
|
||||
| [EquatorFromVector](#EquatorFromVector) | Given an equatorial vector, calculates equatorial angular coordinates. |
|
||||
| [VectorFromHorizon](#VectorFromHorizon) | Given apparent angular horizontal coordinates, calculates horizontal vector. |
|
||||
| [HorizonFromVector](#HorizonFromVector) | Given a vector in horizontal orientation, calculates horizontal angular coordinates. |
|
||||
| [Rotation_EQD_EQJ](#Rotation_EQD_EQJ) | Calculates a rotation matrix from equatorial of-date (EQD) to equatorial J2000 (EQJ). |
|
||||
| [Rotation_EQD_ECL](#Rotation_EQD_ECL) | Calculates a rotation matrix from equatorial of-date (EQD) to ecliptic J2000 (ECL). |
|
||||
| [Rotation_EQD_HOR](#Rotation_EQD_HOR) | Calculates a rotation matrix from equatorial of-date (EQD) to horizontal (HOR). |
|
||||
| [Rotation_EQJ_EQD](#Rotation_EQJ_EQD) | Calculates a rotation matrix from equatorial J2000 (EQJ) to equatorial of-date (EQD). |
|
||||
| [Rotation_EQJ_ECL](#Rotation_EQJ_ECL) | Calculates a rotation matrix from equatorial J2000 (EQJ) to ecliptic J2000 (ECL). |
|
||||
| [Rotation_EQJ_HOR](#Rotation_EQJ_HOR) | Calculates a rotation matrix from equatorial J2000 (EQJ) to horizontal (HOR). |
|
||||
| [Rotation_ECL_EQD](#Rotation_ECL_EQD) | Calculates a rotation matrix from ecliptic J2000 (ECL) to equatorial of-date (EQD). |
|
||||
| [Rotation_ECL_EQJ](#Rotation_ECL_EQJ) | Calculates a rotation matrix from ecliptic J2000 (ECL) to equatorial J2000 (EQJ). |
|
||||
| [Rotation_EQD_EQJ](#Rotation_EQD_EQJ) | Calculates a rotation matrix from equator of date (EQD) to J2000 mean equator (EQJ). |
|
||||
| [Rotation_EQD_ECT](#Rotation_EQD_ECT) | Calculates a rotation matrix from equator of date (EQD) to true ecliptic of date (ECT). |
|
||||
| [Rotation_EQD_ECL](#Rotation_EQD_ECL) | Calculates a rotation matrix from equator of date (EQD) to ecliptic J2000 (ECL). |
|
||||
| [Rotation_EQD_HOR](#Rotation_EQD_HOR) | Calculates a rotation matrix from equator of date (EQD) to horizontal (HOR). |
|
||||
| [Rotation_EQJ_EQD](#Rotation_EQJ_EQD) | Calculates a rotation matrix from J2000 mean equator (EQJ) to equator of date (EQD). |
|
||||
| [Rotation_EQJ_ECL](#Rotation_EQJ_ECL) | Calculates a rotation matrix from J2000 mean equator (EQJ) to ecliptic J2000 (ECL). |
|
||||
| [Rotation_EQJ_HOR](#Rotation_EQJ_HOR) | Calculates a rotation matrix from J2000 mean equator (EQJ) to horizontal (HOR). |
|
||||
| [Rotation_ECT_EQD](#Rotation_ECT_EQD) | Calculates a rotation matrix from true ecliptic of date (ECT) to equator of date (EQD). |
|
||||
| [Rotation_ECL_EQD](#Rotation_ECL_EQD) | Calculates a rotation matrix from ecliptic J2000 (ECL) to equator of date (EQD). |
|
||||
| [Rotation_ECL_EQJ](#Rotation_ECL_EQJ) | Calculates a rotation matrix from ecliptic J2000 (ECL) to J2000 mean equator (EQJ). |
|
||||
| [Rotation_ECL_HOR](#Rotation_ECL_HOR) | Calculates a rotation matrix from ecliptic J2000 (ECL) to horizontal (HOR). |
|
||||
| [Rotation_HOR_EQD](#Rotation_HOR_EQD) | Calculates a rotation matrix from horizontal (HOR) to equatorial of-date (EQD). |
|
||||
| [Rotation_HOR_EQD](#Rotation_HOR_EQD) | Calculates a rotation matrix from horizontal (HOR) to equator of date (EQD). |
|
||||
| [Rotation_HOR_EQJ](#Rotation_HOR_EQJ) | Calculates a rotation matrix from horizontal (HOR) to J2000 equatorial (EQJ). |
|
||||
| [Rotation_HOR_ECL](#Rotation_HOR_ECL) | Calculates a rotation matrix from horizontal (HOR) to ecliptic J2000 (ECL). |
|
||||
| [Rotation_EQJ_GAL](#Rotation_EQJ_GAL) | Calculates a rotation matrix from equatorial J2000 (EQJ) to galactic (GAL). |
|
||||
| [Rotation_GAL_EQJ](#Rotation_GAL_EQJ) | Calculates a rotation matrix from galactic (GAL) to equatorial J2000 (EQJ). |
|
||||
| [Rotation_EQJ_GAL](#Rotation_EQJ_GAL) | Calculates a rotation matrix from J2000 mean equator (EQJ) to galactic (GAL). |
|
||||
| [Rotation_GAL_EQJ](#Rotation_GAL_EQJ) | Calculates a rotation matrix from galactic (GAL) to J2000 mean equator (EQJ). |
|
||||
|
||||
### Gravitational simulation of small bodies
|
||||
|
||||
@@ -2553,6 +2555,25 @@ and so that north represents the direction where azimuth = 0.
|
||||
|
||||
---
|
||||
|
||||
<a name="Rotation_ECT_EQD"></a>
|
||||
### Rotation_ECT_EQD(time)
|
||||
|
||||
**Calculates a rotation matrix from true ecliptic of date (ECT) to equator of date (EQD).**
|
||||
|
||||
This is one of the family of functions that returns a rotation matrix
|
||||
for converting from one orientation to another.
|
||||
Source: ECT = true ecliptic of date.
|
||||
Target: EQD = equator of date.
|
||||
|
||||
| Type | Parameter | Description |
|
||||
| --- | --- | --- |
|
||||
| [`Time`](#Time) | `time` | The date and time of the ecliptic/equator conversion. |
|
||||
|
||||
**Returns**: [`RotationMatrix`](#RotationMatrix)
|
||||
A rotation matrix that converts ECT to EQD.
|
||||
|
||||
---
|
||||
|
||||
<a name="Rotation_EQD_ECL"></a>
|
||||
### Rotation_EQD_ECL(time)
|
||||
|
||||
@@ -2572,6 +2593,25 @@ A rotation matrix that converts EQD to ECL.
|
||||
|
||||
---
|
||||
|
||||
<a name="Rotation_EQD_ECT"></a>
|
||||
### Rotation_EQD_ECT(time)
|
||||
|
||||
**Calculates a rotation matrix from equator of date (EQD) to true ecliptic of date (ECT).**
|
||||
|
||||
This is one of the family of functions that returns a rotation matrix
|
||||
for converting from one orientation to another.
|
||||
Source: EQD = equator of date.
|
||||
Target: ECT = true ecliptic of date.
|
||||
|
||||
| Type | Parameter | Description |
|
||||
| --- | --- | --- |
|
||||
| [`Time`](#Time) | `time` | The date and time of the equator/ecliptic conversion. |
|
||||
|
||||
**Returns**: [`RotationMatrix`](#RotationMatrix)
|
||||
A rotation matrix that converts EQD to ECT.
|
||||
|
||||
---
|
||||
|
||||
<a name="Rotation_EQD_EQJ"></a>
|
||||
### Rotation_EQD_EQJ(time)
|
||||
|
||||
|
||||
@@ -7596,6 +7596,63 @@ def Rotation_GAL_EQJ():
|
||||
[-0.8676668813529025, -0.1980677870294097, +0.4559861124470794]
|
||||
])
|
||||
|
||||
def Rotation_ECT_EQD(time):
|
||||
"""Calculates a rotation matrix from true ecliptic of date (ECT) to equator of date (EQD).
|
||||
|
||||
This is one of the family of functions that returns a rotation matrix
|
||||
for converting from one orientation to another.
|
||||
Source: ECT = true ecliptic of date.
|
||||
Target: EQD = equator of date.
|
||||
|
||||
Parameters
|
||||
----------
|
||||
time : Time
|
||||
The date and time of the ecliptic/equator conversion.
|
||||
|
||||
Returns
|
||||
-------
|
||||
RotationMatrix
|
||||
A rotation matrix that converts ECT to EQD.
|
||||
"""
|
||||
et = _e_tilt(time)
|
||||
tobl = math.radians(et.tobl)
|
||||
c = math.cos(tobl)
|
||||
s = math.sin(tobl)
|
||||
return RotationMatrix([
|
||||
[1.0, 0.0, 0.0],
|
||||
[0.0, +c, +s],
|
||||
[0.0, -s, +c]
|
||||
])
|
||||
|
||||
def Rotation_EQD_ECT(time):
|
||||
"""Calculates a rotation matrix from equator of date (EQD) to true ecliptic of date (ECT).
|
||||
|
||||
This is one of the family of functions that returns a rotation matrix
|
||||
for converting from one orientation to another.
|
||||
Source: EQD = equator of date.
|
||||
Target: ECT = true ecliptic of date.
|
||||
|
||||
Parameters
|
||||
----------
|
||||
time : Time
|
||||
The date and time of the equator/ecliptic conversion.
|
||||
|
||||
Returns
|
||||
-------
|
||||
RotationMatrix
|
||||
A rotation matrix that converts EQD to ECT.
|
||||
"""
|
||||
et = _e_tilt(time)
|
||||
tobl = math.radians(et.tobl)
|
||||
c = math.cos(tobl)
|
||||
s = math.sin(tobl)
|
||||
return RotationMatrix([
|
||||
[1.0, 0.0, 0.0],
|
||||
[0.0, +c, -s],
|
||||
[0.0, +s, +c]
|
||||
])
|
||||
|
||||
|
||||
class ConstellationInfo:
|
||||
"""Reports the constellation that a given celestial point lies within.
|
||||
|
||||
|
||||
Reference in New Issue
Block a user