Kotlin: rotationEqdEcl, rotationEclEqd.

generate/template/astronomy.kt

@@ -4271,6 +4271,41 @@ object Astronomy {
      */
     fun rotationEqjHor(time: AstroTime, observer: Observer): RotationMatrix =
         rotationHorEqj(time, observer).inverse()
+
+    /**
+     * Calculates a rotation matrix from equatorial of-date (EQD) to ecliptic J2000 (ECL).
+     *
+     * This is one of the family of functions that returns a rotation matrix
+     * for converting from one orientation to another.
+     * Source: EQD = equatorial system, using equator of date.
+     * Target: ECL = ecliptic system, using equator at J2000 epoch.
+     *
+     * @param time
+     *      The date and time of the source equator.
+     *
+     * @returns
+     *      A rotation matrix that converts EQD to ECL.
+     */
+    fun rotationEqdEcl(time: AstroTime): RotationMatrix =
+        rotationEqdEqj(time) combine
+        rotationEqjEcl()
+
+    /**
+     * Calculates a rotation matrix from ecliptic J2000 (ECL) to equatorial of-date (EQD).
+     *
+     * This is one of the family of functions that returns a rotation matrix
+     * for converting from one orientation to another.
+     * Source: ECL = ecliptic system, using equator at J2000 epoch.
+     * Target: EQD = equatorial system, using equator of date.
+     *
+     * @param time
+     *      The date and time of the desired equator.
+     *
+     * @returns
+     *      A rotation matrix that converts ECL to EQD.
+     */
+    fun rotationEclEqd(time: AstroTime): RotationMatrix =
+        rotationEqdEcl(time).inverse()
 }
 
 //=======================================================================================

source/kotlin/doc/-astronomy/index.md

@@ -26,7 +26,9 @@ The main container of astronomy calculation functions.
 | [massProduct](mass-product.md) | [jvm]<br>fun [massProduct](mass-product.md)(body: [Body](../-body/index.md)): [Double](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-double/index.html)<br>Returns the product of mass and universal gravitational constant of a Solar System body. |
 | [refractionAngle](refraction-angle.md) | [jvm]<br>fun [refractionAngle](refraction-angle.md)(refraction: [Refraction](../-refraction/index.md), altitude: [Double](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-double/index.html)): [Double](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-double/index.html)<br>Calculates the amount of "lift" to an altitude angle caused by atmospheric refraction. |
 | [rotationAxis](rotation-axis.md) | [jvm]<br>fun [rotationAxis](rotation-axis.md)(body: [Body](../-body/index.md), time: [AstroTime](../-astro-time/index.md)): [AxisInfo](../-axis-info/index.md)<br>Calculates information about a body's rotation axis at a given time. |
+| [rotationEclEqd](rotation-ecl-eqd.md) | [jvm]<br>fun [rotationEclEqd](rotation-ecl-eqd.md)(time: [AstroTime](../-astro-time/index.md)): [RotationMatrix](../-rotation-matrix/index.md)<br>Calculates a rotation matrix from ecliptic J2000 (ECL) to equatorial of-date (EQD). |
 | [rotationEclEqj](rotation-ecl-eqj.md) | [jvm]<br>fun [rotationEclEqj](rotation-ecl-eqj.md)(): [RotationMatrix](../-rotation-matrix/index.md)<br>Calculates a rotation matrix from ecliptic J2000 (ECL) to equatorial J2000 (EQJ). |
+| [rotationEqdEcl](rotation-eqd-ecl.md) | [jvm]<br>fun [rotationEqdEcl](rotation-eqd-ecl.md)(time: [AstroTime](../-astro-time/index.md)): [RotationMatrix](../-rotation-matrix/index.md)<br>Calculates a rotation matrix from equatorial of-date (EQD) to ecliptic J2000 (ECL). |
 | [rotationEqdEqj](rotation-eqd-eqj.md) | [jvm]<br>fun [rotationEqdEqj](rotation-eqd-eqj.md)(time: [AstroTime](../-astro-time/index.md)): [RotationMatrix](../-rotation-matrix/index.md)<br>Calculates a rotation matrix from equatorial of-date (EQD) to equatorial J2000 (EQJ). |
 | [rotationEqdHor](rotation-eqd-hor.md) | [jvm]<br>fun [rotationEqdHor](rotation-eqd-hor.md)(time: [AstroTime](../-astro-time/index.md), observer: [Observer](../-observer/index.md)): [RotationMatrix](../-rotation-matrix/index.md)<br>Calculates a rotation matrix from equatorial of-date (EQD) to horizontal (HOR). |
 | [rotationEqjEcl](rotation-eqj-ecl.md) | [jvm]<br>fun [rotationEqjEcl](rotation-eqj-ecl.md)(): [RotationMatrix](../-rotation-matrix/index.md)<br>Calculates a rotation matrix from equatorial J2000 (EQJ) to ecliptic J2000 (ECL). |

source/kotlin/doc/-astronomy/rotation-ecl-eqd.md

@@ -0,0 +1,18 @@
+//[astronomy](../../../index.md)/[io.github.cosinekitty.astronomy](../index.md)/[Astronomy](index.md)/[rotationEclEqd](rotation-ecl-eqd.md)
+
+# rotationEclEqd
+
+[jvm]\
+fun [rotationEclEqd](rotation-ecl-eqd.md)(time: [AstroTime](../-astro-time/index.md)): [RotationMatrix](../-rotation-matrix/index.md)
+
+Calculates a rotation matrix from ecliptic J2000 (ECL) to equatorial of-date (EQD).
+
+This is one of the family of functions that returns a rotation matrix for converting from one orientation to another. Source: ECL = ecliptic system, using equator at J2000 epoch. Target: EQD = equatorial system, using equator of date.
+
+## Parameters
+
+jvm
+
+| | |
+|---|---|
+| time | The date and time of the desired equator. |

source/kotlin/doc/-astronomy/rotation-eqd-ecl.md

@@ -0,0 +1,18 @@
+//[astronomy](../../../index.md)/[io.github.cosinekitty.astronomy](../index.md)/[Astronomy](index.md)/[rotationEqdEcl](rotation-eqd-ecl.md)
+
+# rotationEqdEcl
+
+[jvm]\
+fun [rotationEqdEcl](rotation-eqd-ecl.md)(time: [AstroTime](../-astro-time/index.md)): [RotationMatrix](../-rotation-matrix/index.md)
+
+Calculates a rotation matrix from equatorial of-date (EQD) to ecliptic J2000 (ECL).
+
+This is one of the family of functions that returns a rotation matrix for converting from one orientation to another. Source: EQD = equatorial system, using equator of date. Target: ECL = ecliptic system, using equator at J2000 epoch.
+
+## Parameters
+
+jvm
+
+| | |
+|---|---|
+| time | The date and time of the source equator. |

source/kotlin/src/main/kotlin/io/github/cosinekitty/astronomy/astronomy.kt

@@ -4271,6 +4271,41 @@ object Astronomy {
      */
     fun rotationEqjHor(time: AstroTime, observer: Observer): RotationMatrix =
         rotationHorEqj(time, observer).inverse()
+
+    /**
+     * Calculates a rotation matrix from equatorial of-date (EQD) to ecliptic J2000 (ECL).
+     *
+     * This is one of the family of functions that returns a rotation matrix
+     * for converting from one orientation to another.
+     * Source: EQD = equatorial system, using equator of date.
+     * Target: ECL = ecliptic system, using equator at J2000 epoch.
+     *
+     * @param time
+     *      The date and time of the source equator.
+     *
+     * @returns
+     *      A rotation matrix that converts EQD to ECL.
+     */
+    fun rotationEqdEcl(time: AstroTime): RotationMatrix =
+        rotationEqdEqj(time) combine
+        rotationEqjEcl()
+
+    /**
+     * Calculates a rotation matrix from ecliptic J2000 (ECL) to equatorial of-date (EQD).
+     *
+     * This is one of the family of functions that returns a rotation matrix
+     * for converting from one orientation to another.
+     * Source: ECL = ecliptic system, using equator at J2000 epoch.
+     * Target: EQD = equatorial system, using equator of date.
+     *
+     * @param time
+     *      The date and time of the desired equator.
+     *
+     * @returns
+     *      A rotation matrix that converts ECL to EQD.
+     */
+    fun rotationEclEqd(time: AstroTime): RotationMatrix =
+        rotationEqdEcl(time).inverse()
 }
 
 //=======================================================================================

source/kotlin/src/test/kotlin/io/github/cosinekitty/astronomy/Tests.kt

@@ -604,6 +604,26 @@ class Tests {
             ),
             "EQJ HOR"
         )
+
+        compareMatrices(
+            Astronomy.rotationEqdEcl(time),
+            RotationMatrix(
+                0.9999856608656787, -0.00535518855821894, -4.305530497609837e-06,
+                0.004911515527973243, 0.917457490583079, -0.39780350675706494,
+                0.002134262929010771, 0.39779778145246825, 0.9174706371286464,
+            ),
+            "EQD ECL"
+        )
+
+        compareMatrices(
+            Astronomy.rotationEclEqd(time),
+            RotationMatrix(
+                0.9999856608656787, 0.004911515527973243, 0.002134262929010771,
+                -0.00535518855821894, 0.917457490583079, 0.39779778145246825,
+                -4.305530497609837e-06, -0.39780350675706494, 0.9174706371286464,
+            ),
+            "ECL EQD"
+        )
     }
 
     //----------------------------------------------------------------------------------------