A.S. Sargsyan1

1 National Polytechnic University of Armenia (Yerevan, Armenia)

The Herouni Mirror Radio Optical Telescope (ROT-54/2.6) is a 54m hemispherical Reflector Antenna built into the mountain Aragats (Armenia) and is combined with a 2.6m optical telescope mounted on the secondary support structure aligned with the Antenna electrical axis. The telescope’s coordinates are Lat. 40.3508609°, Lon. 44.2417924°, and Altitude 1711m. The large 54m hemispherical reflector is illuminated by a movable secondary correcting reflector arm resulting in an effective antenna diameter of 32 m.

The antenna was built in the early 1980s and commissioned in 1987. Observations were carried out until 1995, when first modernization works were realized that continued until the 2001. Basic funding to further maintain the Aragats Scientific Center was available from 2001 to 2010 and concepts for the further operation were done in the frame of a very low mount of funds.

Since 2012, there is effectively no funding for the ROT-54/2.6 and no further maintenance to the structure could be provided. The basic infrastructure is still in a good shape and the Herouni Mirror Radiotelescope could be reactivated given that a few fundamental repairs are being made and funding for the installation and development of new control system and receiving system can be found.

A series of tests were performed on the ROT-54/2.6 radio-optical telescope by the forces of the Herouni United Space Centre (HUSC) in the period September-December of 2020. The radio sources were chosen from the Radio sources catalog, we appointed out that the sources would be able to be watched by the ROT-54/2.6 antenna in its current unmovable state. The HUSC team received professional support in this regard from Dr. John Sargsyan, a leading expert at Parks Observatory in Australia. Based on the calculation of their coordinates and local sidereal time in the sky, the time points for the tracking of ROT-54/2.6 radio telescope antenna through the meridian were determined for that day. Using special geodetic devices, the position of the pendulum bearing the secondary mirror of the ROT-54/ 2.6 radio telescope antenna was measured with a certain allowable accuracy for two axes in relation to the zenith direction from the angle of the azimuth and declination.

Since it is impossible to scan an antenna pattern at declination angle today due to the forced immobility of the East-West axis, it was intended to observe at the multiple sources of CygX in the Cygnus constellation that make up the so-called Loop of Cygnus on December 3.

It was decided to repeat the observation of the same part of the sky at the same time of the observation in the Cyg Loop and, comparing the first and second recordings to conclude that the radio telescope is «breathable» based on the ratio of clearly measurable time deviation of the obtained images.

So, on December 16th the second observation for repeating the previous one was done on the time calculated for “presence” of the same piece of the Sky around the Zenith sector for the ROT-54. The comparative result of the signal processing shows the identity. The curves are matched by those visual similarities and expected time of appearance. There is an approximate difference around 54 minutes between Dec 3 and Dec 16 measurements.

The international Advisory Group (AG), specially formed by European VLBI Network (EVN) recognizes the potential of the ROT-54/2.6 antenna as a single dish instrument and in particular as an element in the European VLBI network. The design and accuracy of the main reflector surface promises a sensitive instrument for frequencies of 1 GHz to 43 GHz, maybe even 90 GHz. The re-activation of the observatory would require a number of tasks to be performed. The conclusion of the article lists a few of the main works that need to be done.

Sargsyan A.S. Current situation and perspectives of the Herouni mirror radiotelescope’s antenna. Radiotekhnika. 2023. V. 87. № 1.
P. 158−166. DOI: https://doi.org/10.18127/j00338486-202301-12 (In Russian)

1. Herouni P.M. The First Radio-Optical Telescope. Trans. of Sixth International Conference on Antennas and Propagation ICAP 89/IEEE-URSI. 1989. V. 1. Р. 540-546.
2. Herouni P.M., Oskanian V.S. Radio Flare at Eta Gemini Star. Proc. of Flare Stars IAU 137th Symposium. Byurakan. 1989. Р. 145-146.
3. Herouni P.M. Construction and Operation of Radio-Optical Telescope ROT-32/54/2,6. Trans. of the URSI International Meeting of Mirror Antenna Construction. Riga. 1990. Р. 34-41.
4. Geruni P.M. Izmerenija harakteristik ROT-54/2.6. VKAI-5. 1990. S. 22-26 (In Russian).
5. Herouni P.M. About Self Noises of Radio-Optical Telescope ROT-54/2.6. Antenna. Journal of Applied Electromagnetism. Trans. Black Sea Region Union of Applied Electromagnetism. Athens, Greece. June 1999. Р. 51-57.
6. Geruni P.M. Gosudarsvennyj jetalonnyj centr po antennym izmerenijam. Sb. nauch. tr. XIX Vsesojuz. konf. po teorii i tehnike antenn. M. 1972. 12 s. (In Russian).
7. Sargsyan A., Kaklamani D. Research on improvement of “Herouni” Mirror Radio Telescope in Armenia”. Report on NATO linkage grant: RMI with Inst. of Commun. Computer Sys. NTUA, Greece. 2000.
8. Sargsjan A.S. Konstruirovanie, izgotovlenie, izmerenie DN i ustanovka DLO na ROT-54/2.6. Sb. tr. Ezhegodnoj konf. GIUA. 2001.
   S. 448-449 (In Russian).
9. Sargsjan A. Nabljudenija razlichnyh ob#ektov na radioopticheskom teleskope ROT-54/2.6”. Vestnik MANJeB. 2003. T. 8. № 7.
10. Sargsyan A., Abrahamyan H., Alkhatib Y., Hakobyan G. Analysis of Feeding Systems for Double Reflector Spherical Antennas.
    IRPhE’2012. Gitutiun Publishing House of the National Academy of Sciences of Armenia. Yerevan. 2013. 219 p.
11. Sargsyan A. Results of ROT Mechanical Constructions Inspection, Proceedings of XXIII International Conference on Radio Telescopes and Radio Interferometers (RR2020). Yerevan. 2020. URL:http://www.jive.eu/jivewiki/doku.php?id=husc:xxiii_interna-tional_conference_on_radio_telescopes_and_radio_interferometers_rr2020 (data obrashhenija: 12.07.2022).
12. Abrahamyan H. Results of ROT broken bracket inspection. Proceedings of XXIII International Conference on Radio Telescopes and Radio Interferometers (RR2020). Yerevan. 2020. URL: http://www.jive.eu/jivewiki/doku.php?id=husc:xxiii_international_con-ference_on_radio_telescopes_and_radio_interferometers_rr2020 (data obrashhenija: 12.07.2022).
13. Sargsyan A., Eyramjyan S. Final Report of Test_2 on the ROT-54, Report to Advisory Group. 2020. URL: http://www.jive.nl/jivewiki/doku.php?id=ztrack (data obrashhenija: 12.07.2022).
14. Sargsyan A., Van’t Klooster K., Eyramjyan S. Several tests were performed before the ROT-54/2.6 de-conservation. NPUA Lraber. Yerevan. 2022. V. 1 (in printing stage now).
15. Sargsyan A., Bach U., Van’t Klooster K., Gurvitz L., et al. 1st Report of the Advisory Group of the Herouni Mirror Radio Optical Telescope (ROT-54/2.6). 2021. URL:http://www.jive.eu/jivewiki/doku.php?id=husc:husc_armenia (data obrashhenija: 12.07.2022).
16. Sargsyan A. On the beginning of the process of de-conservation of the radio optical telescope ROT-54/2.6. Joint International Conference on Astrophysics for Young Scientists. 2021. Byurakan, Armenia. URL: https://www.bao.am/meetings/meetings/Byurakan-spbstu/abstractbook.pdf (data obrashhenija: 12.07.2022).