Astrophysical research at Szeged Observatory

Károly Szatmáry and László Kiss

I. Instrumentation

Szeged Observatory has been controlled by the Department of Experimental Physics of the University of Szeged (earlier József Attila University, JATE) and the Szeged Observatory Foundation since 1992 in cooperation with a few members of the Department of Optics and Quantumelectronics working in similar research fields. Many students are involved into astronomical observations.
The main instrument is a 40 cm Cassegrain telescope equipped with an Optec SSP-5A photoelectric photometer which is supplied with standard UBV and uvby filters or with an SBIG ST-9E CCD camera. A smaller instrument (6.3 cm refracting telescope) with an ST-4 CCD is used for special student works for obtaining digitized images of various faint deep-sky objects. We purchased a Celestron-11 28 cm Schmidt-Cassegrain telescope in 1995. It is equipped with an ST-6 CCD camera which is used for astronomical imaging and photometry using standard UBVRI filters. This telescope deals mostly with the educational work, thus it has been installed in the inner part of the city. A 20 cm Newtonian telescope was bought in order to improve our popularizing work.

II. Research

The basic research field is related to the variable stars, especially to pulsating and eclipsing variables. We use long-term (as long as 40-80 years) data series taken from various international databases compiled by AFOEV, VSOLJ, HAA/VSS, AAVSO, BAA/VSS for studying long-period pulsating variables. Short period pulsators and eclipsing binaries are observed photometrically using the observatory's 40 cm telescope.
In order to describe and model the long-term data series, we applied the very efficient wavelet analysis beyond the traditional Fourier-analyis. The dramatic amplitude decrease in semiregular variable V Boo was succesfully described by the wavelet analysis, while the rapid period decrease in T UMi was explained as an observable effect of the helium shell flash. We have improved the ephemerides of 40 mira variables searching for very long-term period changes.
Pulsational modes of TX Dra were identified and fundamental physical parameters (such as mass, radius and luminosity) were calculated with a complex light curve analysis. We have discussed the light variation of 89 Her which was observed spectroscopically by us at David Dunlap Observatory (Toronto, CA). Recently we studied general properties of 110 semiregular stars.
We have modelled the cyclic O-C diagrams of BE Lyn (high amplitude delta Scuti variable) and TU UMa (RR Lyrae type) as results of the light-time effect in binary systems. The basic properties of the assumed secondary components were calculated (e.g. mass, luminosity, orbital elements).
The light variation of the small amplitude delta Scuti star iota Boo was demonstrated by the most precise photometric measurements so far carried out at Szeged Observatory and Sierra Nevada Observatory (Spain).
We have observed nineteen Cepheids simultaneously in the UBV and uvby photometric systems. Reddenings caused by the interstellar dust, effective temperatures and surface gravities were determined using these photometric data and the most recent theoretical calculations in the literature. This project was extended at Sierra Nevada Observatory by observing 23 fainter Cepheids with the 90 cm telescope equipped with a four-channel Strömgren-photometer.
High resolution spectroscopy of Type I and Type II Cepheids was carried out using the 1.88 m telescope of David Dunlap Observatory (DDO). We have studied the effect of the velocity gradient in pulsating atmospheres on the observed radial velocity curves.
Continuous photometry of the W UMa-type eclipsing binary VW Cep was used for studying the period variation and the slowly changing surface activity. The latter was discussed with high resolution spectroscopy conducted at DDO.
We joined the international observing campaign of the long-period (1100 days) eclipsing binary OW Gem. The main aim was to determine the exact shape of the light curve around the primary minimum. We started the multicolour photometric study of galactic open clusters in 1995. In the following years different observing runs were carried out at Calar Alto Observatory (Spain).
Photometric CCD observations of comets and rapidly rotating non-spherical minor planets were conducted with the 60/90/180 cm Schmidt telescope at Piszkéstetô Station of the Konkoly Observatory.
We attended several international conferences (Brussels, Wien, Visegrád, Baja, Hague, Cape Town, Sion, Los Alamos, Victoria, Kyoto, Montpellier, Leuven, Porto, Budapest, Christchurch, Sydney) during 1990-2003.
Our work has been supported by OTKA Grants T4330, F7318, T7522, T22249, T22259, T32258, T34615, T42509, F43203, MKM K+F Grant 96/593, OM FKFP 0010/2001 and KOMA Grants 96/I/1370, 97/VII/X145.

III. Education and popularization

Regular astronomical teaching is given for students of physics during the fourth year of studies. They get aquired with the photoelectric and CCD photometry in a special laboratory excercise. We announce various special courses every year (Archeoastronomy, Astrophysics, Modern Astronomy, Solar System, Digital Image Processing, Variable Stars), which are very popular among the students. We train astronomers starting from the academic year of 1999/2000 in cooperation with the Department of Astronomy of Eötvös Loránd University and Konkoly Observatory.
Szeged Observatory is open for the public every Friday while there is an open hour for the members of the Hungarian Astronomical Association every Tuesday.
The observatory's URL is:
where one can find our publications and many other astronomical information.