2005 – Kolonica 29.7 – 7.8


Rebič Matúš
Svitič Ján
Záň Adam
Gerboc Tomáš
Michal Vadila
Pauco Martin
Benko Juraj
Dubovsky P. A.
Kačmár Slavomír
Marcin Lubomir
Rusnák Maroš
Vadila Michal Jr.
Kudzej Igor
Kudzejová Michaela
Prokopová Miroslava
Makarivová Natália
Lazorová Iveta


Visual observations. 7 minima of eclipsing binary stars. Physical variables – cepheids. The first (and, as it turned out, the last) visual estimates through a meter telescope.


  1. Variable expedition in a new dress

Summary: The article brings the results from the summer transformation expedition in Slovakia.

For the second year in a row, I had the opportunity to participate in the historically oldest Slovak regular expedition dedicated to observation of variable stars. There have been significant changes compared to last year. The organizers understood that at a time of unprecedented development of observation techniques, changes had to be made to the content of the expedition. But let’s go in order.

The Variable 2005 expedition took place from 29.7 to 7.8.2005 at the astronomical observatory of the Vihorlat Observatory in Kolonica saddle. The organizers were the Vihorlat Observatory itself, headed by the director of RNDr. Igor Kudzej and local group of Slovak Union of Amateur Astronomers in Snina represented by the chairwoman of RNDr. Iveta Lazorová. The first change was already in the expedition line-up. Instead of a number of young observers from the ranks of high school students, there were more experienced amateur observers – former long-time participants of Variable Juraj Benko, Tomáš Gerboc, Ľubomír Marcin, Slavomír Kačmár, Maroš Rusnák and Michal Vadila. Of the youngsters, only the best Martin Pauco, Matúš Rebič and Ján Svitič came. The aim of the expedition was not to make quantitatively many observations, but to prepare a new model of expedition that would have benefits in the field of education and would also bring scientifically useful data.

The most noticeable are changes in the software area. Slavo Kačmár brought to the expedition Excel sets of predictions.xls and protocols.xls, which largely automate the selection of observed eclipsing binaries and subsequent data processing. When selecting stars, we focused on those with few observed minima. At the same time, of course, we encountered the problem that these stars do not have ready charts. Therefore, the software arsenal has been operationally expanded with a set of kolomap.xls, which allows you to quickly produce a map using the star atlas Cartes du Ciel.

In addition to eclipsing ones, physical variables were also observed. We followed up on last year’s observations of selected cepheids. Already on the first evening, a heated discussion broke out about the methodology of observation. In short, we could call it “rods vs cones “. In other words, how to perceive the color differences between a variable and comparison stars. Disagreements were reflected in the accuracy of the results. A year ago, young observers observed through direct vision using Otero’s methodology and, despite their inexperience, never deviated more than 0.1 mag from the photoelectric curve in the V filter. This year, everyone watched as they wanted and the results are much worse.

Results of observations:

Of the 9 nights, 2 were perfectly clear and 4 partially clear. Technique used:

  • Artillery binocular 12 x 60
  • Somet binar 20 x 100 in the number of two
  • Cassegrain 150 mm
  • Lichtenknecker 150 mm
  • Newton 265 mm HUGO
  • Reflector 265 mm DANDELION

Except for binoculars, all instruments were equipped with a equatorial mount with a clock drive. The observatory’s largest instrument with a mirror diameter of 1 meter was also unexpectedly involved in the observation. It is currently intensively preparing for the installation of a two-channel photometer. However, it can also be looked through visually. So I couldn’t resist and made an estimate of the cataclysmic EM Cyg and blazar 3C454.3, which had just weakened after flaring up to 16.1 mag. What is interesting about it is the estimated distance. It’s over half the universe, so to speak, — 7 billion light-years.

Minima of 7 stars have been observed among eclipsing variables, with 3 being especially valuable in the little-observed stars V836 Cyg, V 859 Cyg and V1073 Her. A sympathetic story is connected with the observation of GZ And. On the expedition, two observers diligently observed it, but only measured noise. The mystery was explained only at a September practice for variable star observers, which the Vihorlat Observatory also regularly organizes in Kolonica. Paradoxically, complete beginners drew attention to the fact that the star is somehow foggy. With greater magnification, it turned out to be a tight pair. A consultation of the literature confirmed that it is indeed even a quadruple star system, where the variable is component A, which, however, decreases in brightness at a minimum below component B. So, to observe the minimum in compound light is practically impossible. The lesson is that before each observation, it is good to study the available articles about the star, even if the observer is influenced to some extent.

In the field of physical variables, cepheids have been observed: Delta Cep, Eta Aql and TU Cas, as well as some semiregular variables from the MEDUZA program.


The Variable expedition clearly went from quantity to quality of observations. The most interesting results are the minima of the eclipsing V836 Cyg, V 859 Cyg and V1073 Her, the “revealing” of GZ And, the first visual observations of variable stars with a meter telescope, software products prediction.xls, protocols.xls and kolomaps.xls.

Comparison of photoelectric and visual observations with the naked eye of the cepheid Eta Aql.