History

The Perek’s 2-metre telescope in Ondřejov has been in operation since 1967, when it was commissioned on the occasion of the XIII General Assembly of the International Astronomical Union (IAU). The construction of the dome began in April 1963.

The construction of the Perek’s 2m telescope started in January 1966 by Zeiss in Jena, and in October 1966, the telescope was transferred to the Astronomical Institute and consequently disassembled and moved in parts to Ondrejov where it was again reassembled. This final assembly was completed in February 1967 and first light through a eyepiece occurred on 8th March 1967. The telescope was officially inaugurated on 23rd August 1967 during the XIII. International Astronomical Union General Assembly. The first spectrum was acquired on 13th October 1967.

From the beginning, the telescope was primarily used for spectroscopy. Initially the spectra were first exposed on photographic plates and from 1992 electronic detectors were used. From 1992 to 2000 a Reticon detector was used and since 2000 CCD chips.

Upgrades of the telescope

In the past, two major improvements of the telescopes were successfully performed. In 2007, modernization of the driving electronics was performed. This included the replacement of the position sensors and the driving software. The original electronics that were unique and hence irreplaceable were replaced with standard commercial electronics.

In 2009 all the telescope mirrors were recoated, which significantly improved the telescope performance.

The most significant and fundamental upgrade of the telescope during last decades was performed by the group in 2019. The optical configuration was completely changed, which led to an increased efficiency of the optical system. Previously, the light was reflected to the coudé spectrographs with a system of mirrors. However, the reflecting surfaces slowly degrade with time that leads to an exponential decrease of the total efficiency. It is now possible to observe even very faint objects. The main part of the upgrade was putting the optical fibers from the primary focus to the coudé rooms, where the spectrographs are placed. As a result, only one reflecting surface (i.e., the 2‑m primary mirror) is present instead of four mirrors, which was before. With this upgrade of the telescope, higher efficiency and extension of the observational limits were achieved. The possibility of observing fainter objects broaden the number of observing programs which can be performed with the Perek 2‑m telescope.

The last reconstruction of the Perk telescope is described by Miroslav Šlechta in the article Modernization of the 2m Perk telescope in Ondřejov (in Czech), which was published in the Astropis magazine (volume: 2020, issue: 3, pp.: 12–15).