kepleq

 Procedure Abstract Required_Reading Keywords Declarations Brief_I/O Detailed_Input Detailed_Output Parameters Exceptions Files Particulars Examples Restrictions Literature_References Author_and_Institution Version

#### Procedure

```      KEPLEQ ( Kepler's Equation - Equinoctial Version )

DOUBLE PRECISION FUNCTION KEPLEQ (ML,H,K)

```

#### Abstract

```    This function solves the equinoctial version of Kepler's
equation.
```

```     None.
```

#### Keywords

```     SPK
```

#### Declarations

```
IMPLICIT NONE
DOUBLE PRECISION  ML
DOUBLE PRECISION  H
DOUBLE PRECISION  K

```

#### Brief_I/O

```     VARIABLE  I/O  DESCRIPTION
--------  ---  --------------------------------------------------
ML         I   Mean longitude
H          I   h component of equinoctial elements
K          I   k component of equinoctial elements
```

#### Detailed_Input

```     ML         mean longitude of some body following two body
motion.  (Mean longitude = Mean anomaly + argument
of periapse + longitude of ascending node.)

H          The h component of the equinoctial element set
( h = ECC*SIN( arg of periapse + long ascending node) )

K          The k component of the equinoctial element set
( k = ECC*COS( arg of periapse + long ascending node) )

Note that ECC = DSQRT ( K*K + H*H )
```

#### Detailed_Output

```     The function returns the value of F such that
ML = F + h*COS(F) - k*SIN(F)
```

#### Parameters

```     None.
```

#### Exceptions

```     1) If the sum of the squares of F and K is not less than .9
the error 'SPICE(ECCOUTOFBOUNDS)' will be signalled.

2) If the iteration for a solution to the equinoctial Kepler's
equation does not converge in 10 or fewer steps, the error
'SPICE(NOCONVERGENCE)' is signalled.
```

#### Files

```     None.
```

#### Particulars

```     This routine solves the equinoctial element version of
Kepler's equation.

ML = F + h*COS(F) - k*SIN(F)

Here F is an offset from the eccentric anomaly E.

F = E - argument of periapse - longitude of ascending node.

where E is eccentric anomaly.
```

#### Examples

```     None.
```

#### Restrictions

```     None.
```

#### Literature_References

```     "Optical Navigation Program Mathematical Models" JPL
Engineering Memorandum 314-513.  By William M. Owen
August 9, 1991.
```

#### Author_and_Institution

```     W.L. Taber      (JPL)
```

#### Version

`    SPICELIB Version 1.0.0, 11-DEC-1996 (WLT)`
`Wed Apr  5 17:46:49 2017`