Ruby/WCS

WCSTools wrapper for Ruby. Provides calculation and conversion of sky positions in astronomical coordinates.

Installation

Install WCSTools library. For RedHat Linux:
```
$ yum install wcstools-devel
```
Or download source code and install.
Install Ruby/WCS. Install from RubyGems as:
```
$ gem install wcs
```
Or install from source code:
```
$ ruby setup.rb
```
Or add this line to your application's Gemfile:
```
gem 'wcs'
```
And then execute:
```
$ bundle
```

Usage

require 'wcs'
naxis1  = 100  # Number of pixels along x-axis
naxis2  = 100  # Number of pixels along y-axis
ctype1  = "RA--TAN" #  FITS WCS projection for axis 1
ctype2  = "DEC-TAN" #  FITS WCS projection for axis 2
crpix1  = 0    # Reference pixel coordinates
crpix2  = 0    # Reference pixel coordinates
crval1  = 0    # Coordinate at reference pixel in degrees
crval2  = 0    # Coordinate at reference pixel in degrees
cd      = nil  # Rotation matrix, used if not NULL
cdelt1  = 0.1  # scale in degrees/pixel, if cd is NULL
cdelt2  = 0.1  # scale in degrees/pixel, if cd is NULL
crota   = 0    # Rotation angle in degrees, if cd is NULL
equinox = 2000 # Equinox of coordinates, 1950 and 2000 supported
epoch   = 2000 # Epoch of coordinates, for FK4/FK5 conversion

wcs = Wcs::WorldCoor.new(naxis1,naxis2,ctype1,ctype2,
  crpix1,crpix2,crval1,crval2,cd,cdelt1,cdelt2,
  crota,equinox,epoch)
xpix,ypix = wcs.wcs2pix(0.5,0.5)
xpos,ypos = wcs.pix2wcs(50,50)

ra = 0
dec = 0
l,b = Wcs.wcscon(Wcs::J2000,Wcs::GALACTIC,0,0,ra,dec,2000)

Platforms tested

ruby 2.0.0p0 (2013-02-24 revision 39474) [x86_64-linux]

Copying License

This program is free software. You can distribute/modify this program under the same terms as LGPL. See "COPYING" file. NO WARRANTY.

Author

Masahiro TANAKA