Faculty of Mathematics, Physics
and Informatics
Comenius University Bratislava


Since 1995 accurate astrometric observations of asteroids and comets have been performed in Modra Observatory. As these data are needed for orbit calculations they are sent to Minor Planet Center in Cambridge, U.S.A., and published in Minor Planet Electronic Circulars and in Minor Planet Circulars with the observatory code 118 along with observations from other Observatories. (The latest observations from around the world can be found here.

Newly discovered objects on unusual orbits are placed at http://cfa-www.harvard.edu/iau/NEO/ToConfirm.html and so called near Earth asteroids on orbits with large uncertainty that diminish their brightness have priority in astrometric observations. CCD camera AP8 (SBIG ST6 up to June, 1998, ST8 up to 2003) is now in the primary focus of a telescope - 60 cm reflector with focal length of 330 cm. Dozens of asteroids were *discovered* with this equipment. The orbits for some of them are known with high precision and they are cataloged (and a few are even named). (More information about Modra asteroids can be found here.)

Along with astrometric observations photometric observations <photometric> were added since 1998. These are needed for asteroid shape and rotational period determination. Sometimes even surface features can be anticipated or pole coordinate estimated. Usually, we are able to provide photometry of asteroids down to +16 magnitude with relatively high accuracy.

Test observations were executed on main belt asteroids with known rotational period and amplitude. At the beginning of 2003 suitable occasion for photometric observations of one of the Modra discoveries was set in! The asteroid denoted (28753) 2000 HA was near the perihelion of its orbit and at the same time near opposition. As such event is extraordinary in Slovakia - to analyze the properties of one of its own discovery - this one was included to observational program. Synodic rotational period was determined from the light curve to be 4.994 hours and the shape is elongated (amplitude is about 1.0 mag).

Poorly known near Earth asteroids have the *priority* in *photometric* observations. In this manner the observations and results are continuously consulted with observatory AV ČR in Ondřejov.

The list of known Minor Planet Lightcurve Parameters is here.

The list of all Modra photometric asteroid campaigns is here.