++ed by:
1 non-PAUSE user
Sergey Krushinsky
and 1 contributors

# NAME

Astro::Montenbruck::CoCo - Coordinates conversions.

Version 0.01

# DESCRIPTION

Celestial sphera related calculations used by Astro::Montenbruck modules.

# FUNCTIONS

## equ2ecl(\$alpha, \$delta, \$epsilon)

Conversion of equatorial into ecliptic coordinates

### Arguments

• \$alpha — right ascension

• \$delta — declination

• \$epsilon — ecliptic obliquity

### Returns

Ecliptic coordinates:

• \$lambda

• \$beta

All arguments and return values are in degrees.

## ecl2equ(\$lambda, \$beta, \$epsilon)

Conversion of ecliptic into equatorial coordinates

### Arguments

• \$lambda — celestial longitude

• \$beta — celestial latitude

• \$epsilon — ecliptic obliquity

### Returns

Equatorial coordinates:

• \$alpha — right ascension

• \$delta — declination

All arguments and return values are in degrees.

## equ2hor(\$h, \$delta, \$phi)

Conversion of equatorial into horizontal coordinates

### Arguments

• \$h — the local hour angle, in degrees, measured westwards from the South. `h = Local Sidereal Time - Right Ascension`

• \$delta — declination, in arc-degrees

• \$phi — the observer's latitude, in arc-degrees, positive in the nothern hemisphere, negative in the southern hemisphere.

### Returns

Horizontal coordinates:

• azimuth, in degrees, measured westward from the South

• altitude, in degrees, positive above the horizon

## hor2equ(\$az, \$alt, \$phi)

Convert horizontal to equatorial coordinates.

### Arguments

• \$az — azimuth, in degrees, measured westward from the South

• \$alt — altitude, in degrees, positive above the horizon

• \$phi — the observer's latitude, in arc-degrees, positive in the nothern hemisphere, negative in the southern hemisphere.

### Returns

Horizontal coordinates:

• hour angle, in arc-degrees

• declination, in arc-degrees

# SUPPORT

You can find documentation for this module with the perldoc command.

``    perldoc Astro::Montenbruck::CoCo``

# AUTHOR

Sergey Krushinsky, `<krushi at cpan.org>`