Presentation

Hello and welcome in the neighbourhood of the Alpha Centaurii system known as under the name of Rigel Kentaurus. I hope that you spent a pleasant travel about 4,3 light years at the speed of light. In some billion kilometres on your left is Proxima Centaurii, the nearest star of our planetary system. So, I'm going to present you AlphaCentaure, a software intended for the observation of the sky for amateur astronomers (hmmm...although this software has only a utility for the Sol system)..

AlphaCentaure is a planetarium software which can be used in complement with the other astronomy softwares. It is always in beta version and I had too many problems to run it under Windows 2000 and XP. I have not tested it under Windows 95 / 98 / NT yet, but I think that there will be too many problems to launch (finally I hope).

Here is the required configuration:

• Windows 95/98/NT4/2000/XP (the future is not Microsoft®©^TM it's Open Source)
• At least 64 Mo of RAM
• At least 120 Mb of hard disk (if you decide to install it with all star catalogs and extragalactic objects)
• A screen resolution of 800x600 at least and more 256 colors (to have color gradations and the display of the earth map)
• And as processor, at least a Pentium (or other from Cyrix, or AMD), let's say that this software is rather greedy in calculation...

What can do Alphacentaure ? Bah...full of things:

• A view of the celestial sphere on which is printed stars, extragalactic objects, constellations, planets, comets and astroids
• One graph displaying various elongations of the visible planets to the naked eye during one year, what allows to know for example at which moment Mercury is visible in the morning or in the evening, or still is i in conjunction with the other planets
• A view of planets with regard to the Sun if the observer was placed outside of the solar system
• A view representing the parts day and night of the planet
• For other options, please consult the online documentation (in the course of editorial staff) and glance at screen shots.

What can't do AlphaCentaure ? Bah...full of things too:

• Print out of maps
• Drive motorized telescopes
• etc...

Precision of the calculations
The position in right ascension and declination of these various celestial bodies is rather precise but not so precise as the data published by Connaissance des Temps or by Annuaire du Bureau des Longitudes. AlphaCentaure is useful for the study of the constellations, the moments to raise and set of celestial bodies, the trajectory of planets, etc.... The more one takes away in the time (before or after J2000), and the more the calculations become less and less precise. Anyway, the software is limited by 9999 BC to 9999 AC (even if that does not want to say big thing ;).

Used catalogues
AlphaCentaure uses several catalogs resulting from main sites. These catalogs, in raw text format, are then compiled to have a more compact binary format and which contain only essential information (for example, for stars, will be reserved: the name, the serial number, proper motion in right ascension and declination, radial speed, magnitude, spectre, type of the star and the coordinates in right ascension and declination for J2000). The various used catalogs are:

For stars:

• Master Star Catalogue, version 2
• Guide Star Catalogue, version 1.1 (sur 2 CDROM) (not available online)
• Tycho-2 (not available online)
• Washington Double Star Catalogue
• General Catalogue of Variable Stars

• Abell (Rich clusters of galaxies)
• Catalogue of galaxies behind the Milky Way
• Catalogue of HII Regions
• Catalogue of principal Galaxies
• Fourth Cambridge Survey of Radio Sources
• Globular Clusters in the Milky Way
• Index Catalogue
• Lynd's catalogue of Bright Nebulae
• Lynd's catalogue of Dark Nebulae
• Markarian galaxies
• Morphological Catalogue of Galaxies
• New General Catalogue
• Saguaro Astronomy Club Database
• Strasbourg-ESO Catalogue of Galactic Planetary Nebulae
• Third Reference Catalogue
• Uppsala General Catalogue of galaxies

Term of service
AlphaCentaure is a freeware, i.e. you can download it, make multiple copies, distribute it freely to your friends. Any marketing of this software is strictly prohibited. ;)
As this software is a freeware, I do not guarantee the malfunction on such or such machine, and in more I am not responsible for what you go to do with it.

Astrometric data of Alpha Centaurii

Proper name	Rigel kentaurus
Bayer's letter	Alpha
HD number	128620
Right ascension (J2000)	14h 39mn 36.2s
Declination(J2000)	-60° 50' 07"
Visual magnitude	-0.01
Absolute magnitude	4.35
Spectral class	G2 V
Distance	4.39 light-years
Raidal proper motion	3.678"
Direction	281°
Spatial speed	34
Radial speed	-25 km/s
Parallax	0.743"
Diametre (Sun=1)	1.3
Luminosity (Sun=1)	1.4

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