/astronomy-get-constellation-by-coords

Perl script getting constellation name by equatorial coordinates

Primary LanguagePerl

Description

This script is Perl implementation of VI/42 Identification of a Constellation From Position (Roman 1987). Based on C code of program.c

Requirements:

  • data.dat from VI/42 (direct link) or from this package
  • Getopt::Long
  • Math::Trig

Usage

Usage (from console):

$ ./constByCoords.pl [--ra HH.hhhh --dec DD.dddd [--epoch YYYY.0] [--quiet]]

Note: instead HH.hhhh or DD.dddd you can use HH:MM:SS.ss or DD:MM:SS.ss (see below)

Options:

List of options:

  • --ra — RA (α), right ascension of the celestial object
  • --dec — DEC (δ), declination of the celestial object
  • --epoch — Epoch of the coordinates (default 2000.0)
  • --quiet — Print only constellation name

Examples:

Example 1. Without any option:

$ ./constByCoords.pl

Output:

Usage: ./constByCoords.pl [--ra HH.hhhh --dec DD.dddd [--epoch YYYY.0] [--quiet]]

Note: instead HH.hhhh or DD.dddd you can use HH:MM:SS.ss or DD:MM:SS.ss`

Example 2. Using format HH.hhhh, DD.dddd (Sirius, α CMa)

$ ./constByCoords.pl --ra=6.75230861111 --dec=-16.7215361111

Output:

RA = 6.7523 Dec = -16.7215 is in Constellation: CMa

===============The Equinox for these positions is: 2000.0

Example 3. Using format HH:MM:SS.sss, DD:MM:SS.sss (Regulus, α Leo)

$ ./constByCoords.pl --ra=10:08:22.053 --dec=+11:58:02.05

Output:

RA = 10.1395 Dec = 11.9672 is in Constellation: Leo

===============The Equinox for these positions is: 2000.0

Example 4. Using epoch 1950.0 instead default 2000.0

$ ./constByCoords.pl --ra=6.2222 --dec=-81.1234 --epoch 1950.0

Output:

RA = 6.2222 Dec = -81.1234 is in Constellation: Men

===============The Equinox for these positions is: 1950.0

Example 5. Using qiuet mode (print only constellation name)

$ ./constByCoords.pl --ra=9.4555 --dec=-19.9000 --epoch 1950.0 --quiet

Output:

Hya

Some example data got from README file of VI/42