What is Albireo ?

Albireo is a program for computation of binary star's ephemeris. It computes actually the separation and the position angle at given dates. The computation of these ephemeris is based upon seven orbital elements which should be entered carefully in the form below. It is also possible, for star with known orbits, to use a database file containing more than 1000 stars. This file is up to date (August 1998) for the orbits published on IAU circulars. Some recent published papers may not have been included yet. The orbital elements used by this program come from the latest published orbit of each star.
Just enter the name of the star, the seven orbital elements (if you don't want to use the database data) and the date you want the ephemeris being computed, and click the button. The result will appear soon onto your browser window.

The soft is still under developpement. Error handling is actually rather poor and if you omit a value (ex : the start date) the program may behave strange...
Bugs report, comment and suggestions are welcome and will be taken into account when I have time for... (email me)


Q : The star is in the database and I get the message "Error : Star not in database"
Check first that hou have entered correctly the star id. (ex. cou 612), or the ads number (ex. ads 224) or the hr number (ex: hr 2324). Even if Ok, There is actually a bug and I get it when I put no end date and no interval. Try to put a end date and an interval, it should work.

Q : I don't know the orbital elements of my double star. Is it possible to compute anyway ?
You can look at the database by clicking here. If your star is in the database, just type his name in the "Star's name" field of the form above (and of course the dates you want the ephemeris to be computed between).

Q : The orbital elements in the database seems to be wrong. What can I do ?
Enter yours in the above fields, the database entry will be ignored. If you are sure that my values are false, or if yours are better, please tell me (email me).

Q : What happens if I enter only some of the required orbital elements ?
If a parameter is missing then the program will automatically search in the database and displays the ephemeris if the star is found (and if the star is not foud... I don't know what will happend).

This page and the soft are (poorly) maintained by Eric Aristidi (email me).
Last modification : 4 Sep 2004.

The orbit database is maintained by Marco Scardia, Merate, Italy

The formulas used for the ephemeris are from Paul Couteau, L'observation des étoiles doubles visuelles, Eds. Flammarion, Paris, 1978.

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