Črni Vrh Observatory

The Observatory

Comet Observations

Comet observations at Crni Vrh are dating back for twenty years when the first photographs of comet West were taken in the early morning of March 4, 1976. At that time, the comet was an easy naked eye object, well visible even in broad morning twilight. At the very beginning, remarkable results were obtained with second-hand photographic lenses.

In 1985, the new observatory was built by the author on a more favorable location but still close to Crni Vrh. It was equipped with fast, short focus cameras like 19-cm, f/4 flat field Schmidt-Cassegrain and later 20-cm, f/2 Baker-Schmidt, as well as few high quality lenses for wide field observations. In addition, the observatory had its own laboratory with all the necessary equipment for gas hypersensitization of photographic emulsions. This was a good instrumental base to continue and even extend the comet observations to fainter magnitudes. At the same time, visual observations also started on a regular basis.

Numerous faint and brighter comets of the late 80's and early 90's were successfully observed. Among the brighter comets, extensive observations of comets C/1989 Q1 Okazaki-Levy-Rudenko, C/1989 X1 Austin and C/1990 K1 Levy were done.

When the commercial CCDs became available in the early 90's, they considerably affected the comet observations and brought the new possibilities in this field. The new technique required some familiarity with computers and electronics, and was introduced with invaluable help of Bojan Dintinjana, astronomer and computer specialist at the University of Ljubljana Astronomical Observatory. In 1989, we started to experiment with the SBIG ST-4 and obtain initial experience. Lacking a good observing site, the University of Ljubljana installed their 36-cm S-C telescope and CCD at the observatory in 1990. The CCD was of research grade and it was possible to use it for cometary observations when not used for University observing programs.

Outstanding capabilities of CCDs enable us to start comet observations using narrow band filters and CCD photometry with standard V filter. Remarkable results with these filters were obtained on comets 109P/Swift-Tuttle and 1996 B2 (Hyakutake). Encouraged also by Dan Green of CBAT, who lacked information on faint comets, the program of comet CCD photometry became regular in 1992 and continues until today.

Asteroid Observations

Our first minor planets were found incidentally on Jan. 30 and February 1, 1997 in the CCD field of periodic comet 119P/Parker-Hartley. They received provisional designations 1997CQ13 and 1997BR8. Seven more were found later that year by deliberate searching with the 36-cm telescope and CCD. The systematic observations of Main belt, NEO and other asteroids started in late 1997, when J. Skvarc and S. Maticic joined the observing staff. At the same time, the ACIT imaging system has been put in test operation and the first version of Fitsblink software for image analysis became available.

Observing site

Regular astronomical observations started in 1975, when a small observatory, equipped with the home-made instruments was set up close to the village of Crni Vrh, near the historical town Idrija. The present observatory was built in 1985 on a woodland region of Western Slovenia, at an altitude of 730m. The site is well above the inversion border during most of winter season, enabling undisturbed observations on many successive clear nights. In total, there are about 150 clear nights per year, useful for any kind of observations.

View of the Crni Vrh Observatory during the years 1985-2001

Observations at the site are performed also by Department of Physics, Astronomical Observatory, in Ljubljana.

Weather Statistic

Reconstruction works in 2001

Extensive reconstruction works were carried out during the May-December 2001 period. The roll-off roof drive system needed to be modernized after 16 years of continuous operation. On the other hand, we decided to build a new 60-cm telescope in order to improve our ability for detection of faint objects. In order to simplify the operation of our telescopes, we decided to put both existing telescopes and the new 60-cm one under the same roof. Additional argument in favour of such a decision was also our intention to operate the telescopes remotely over the internet.

Current view of the observatory, after the complition of reconstruction works in 2001

The old roof was raised by 30 cm and the drive system and rails were removed completely. To make space for the new 60-cm telescope, a new shelter for the existing telescopes was addedd along the eastern part of the building. The observatory now has two observing rooms, containing three telescopes. The new rails and chain-drive system were installed in June. It works much more smoothly and reliably. Also we improved the operation security by adding double limiting switches.

The reconstruction works took some 1400 hours of voluntary work.