ruby-sphere README

ruby-sphere is an application to calculate apparent positions of stars with a moderate accuracy.

Requirements

Ruby 1.8 <URL:http://www.ruby-lang.org/> or newer.: optparse is required by bin/visibility. Might also work on Ruby 1.6.x with ruby-sumo but not tested.
gnuplot <URL:http://www.gnuplot.info/>: Visibility plot is created through gnuplot.

Download

Latest version at <URL:http://sourceforge.net/project/showfiles.php?group_id=122091>.
Cutting edge version via cvs.

Install

De-compress archive and enter its top directory. Then type:

($ su)
# ruby setup.rb

These simple step installs this program under the default location of Ruby libraries. You can also install files into your favorite directory by supplying setup.rb some options. Try "ruby setup.rb --help".

If you want to install the library under /usr/local, you might want to run

$ ruby setup.rb config --prefix=/usr/local --siteruby=/usr/local/lib/ruby/site_ruby
$ ruby setup.rb setup
# ruby setup.rb install

Useful make targets

Following targets are provided for users. Have a look in Makefile for other targets.

test (default): run the tests
install/config/setup: same as "ruby setup.rb install", "ruby setup.rb config", or "ruby setup.rb setup"
doc: create API document as HTML files in the doc/ directory

Usage

Try

$ ruby -I./lib bin/visibility -c sample/planets.conf

before installation or

$ visibility -c sample/planets.conf

after installation.

Please have a look in sample/planets.conf for a brief description of configuration files.

You can also build your own applications referring the API document.

Contact

Please report bugs and patches, request for features at the SourceForge.net Trackers.

Limitations

The package currently aims to provide an easy-to-use way of planning observations. This is not suitable to acquire your target into your telescope field of view.

Time scales

All calculations are done on J2000.0: Greenwich apparent sidereal time is assumed to be the same as Greenwich mean sidereal time.
TT: terrestrial time is assumed to be the same as UTC: coordinated universal time.

Coordinates

Aberrations of light (20 arcsec for non-solar system objects):
- annual aberration,
- planetary aberration,
- differential aberration, and
- light-deflection,
nutation, and precession are not taken into account.

Planets

Position precision of planets are more or less 0.01 degrees with no perturbations taken into account.
Positions of the Moon, as long as other planets and stars, are calculated with geocentric coordinates. The Moon as viewed from a place on the earth is different up to +/- 1 degree.
Moon phase is calculated using geocentric coordinates.

Conversions to Azimuth and Elevation

Atmospheric dispersion (35 arcmin at horizon) is not taken into account.
The earth is assumed to be perfectly spherical.

License

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA