Orgov Radio-Optical Telescope


The Orgov Radio-Optical Telescope, also known as ROT54 or the Herouni Mirror Radio Telescope, is a radio telescope in Orgov, Armenia.
Radiotelescope ROT-54/2.6 is planned to be launched in close cooperation with the international scientific community to implement long-term scientific research projects. Radiotelescope ROT-54/2.6 will be launched to solve scientific and applied problems in the field of Astronomy and Radio Astronomy and Deep Space Communication.
The Armenian Scientific School of Antenna Engineering was established in Armenia under the leadership of academician Paris Herouni. The established structure had a positive influence on the socio-economic situation in neighboring rural settlements of Orgov and Tegher. The Science Center of Aragats was built near Orgov in 1975, which is a testing ground for precise antenna measurements, where the world's exclusive radio-optical telescope ROT-54/2.6 is located. Applications of the Herouni radiotelescope are the study of the Universe and Deep Space Communications.
Restarting the ROT-54/2.6 radiotelescope and the development of the antenna measurement range makes it possible to conduct various and numerous research and educational research activities.
Most of the sensational discoveries of recent years, for example, photo of the black hole, supernova explosions, the diamond planet in a distant galaxy, strange radio bursts that have no explanation were made with the help of telescopes which are alike radiotelescope ROT-54/2.6. The Armenian radiotelescope ROT-54/2.6 can receive funding within the framework of similar international programs, get recognition at the proper level, presenting Armenia on the scientific map of the world as an advanced ideas and cutting-edge technologies.

PREHISTORY OF FOUNDATION

Issues

In the half of the 20th century, the USSR made huge expenditures for the development of the scientific sphere, which was due to scientific and military competition with the United States, in particular, intense competition in the field of conquering the universe.
Soviet Armenia took a direct part in the process of developing scientific and technical capabilities and power to solve the country's defense issues. As you may know, people with higher and secondary vocational education were registered in Armenia with the highest percentage in the USSR, accounting for about 20% of the total population of the Republic. Therefore, in parallel with the rapid development of industrial, applied, and fundamental science in Soviet Armenia, numerous big enterprises were created and successfully operated in the fields of chemistry, heavy industry, astronomy, and modern physics. Higher educational institutions in Yerevan have trained a large number of graduates in radiophysics and radio engineering.
All-union Scientific Research Institute of Radio Physical Measurements was created in 1971 by an outstanding scientist, Doctor of Technical Science Paris Misak Herouni, who acted in the sphere of double subordination to the state standard of the USSR and the military-industrial complex. Since its foundation until the collapse of the USSR in 1991, the Institute was the leading enterprise of the USSR in the field of antenna metrology, where a huge amount of work was done for the welfare of the country, including many orders of military-industrial significance. Several new scientific directions were founded, and the Armenian scientific school of antenna engineering was formed and developed at that time as well. ASRIRPM greatly contributed to the recognition of Armenia as a leading science and technology Republic, which undoubtedly provided the spread of the good reputation of science in Armenia.
In the 1980s, the number of employees of the Institute of the ASRIRPM was 800 -1,000, and the annual turnover was two hundred million Soviet rubles. Since the ASRIRPM was the leading research enterprise in the USSR and played a leading role in its field, at the same time it operated with the Union's financial resources, while all human and property resources belonged to Armenia.

Goal

Professor Herouni, having created the scientific polygons of the ASRIRPM on the southern slope of Aragats, wanted to implement theoretical achievements in practice, that is, to make devices out of metal, therefore, to materialize. That is, to turn theoretical into the practical. For this purpose, in a short time, he traveled all over Armenia to find the appropriate territory for future research sites.
In the early 1970s, the location of the Science Center of Aragats was established at the state level between the villages of Orgov and Tegher, which at that time were located in the Aragats district. At that time, the population of Tegher village had already moved to the Proshyan state farm in the Ararat valley due to the lack of roads, electricity, water supply, radio, and other infrastructure. A similar move was envisaged for the residents of the village of Orgov.
In the first years of the creation of the SCA, a road and water supply were built, electricity was provided, and other infrastructure was built, which became a good prerequisite for ensuring social conditions in villages. At the same time, residents of the villages of Orgov, Tegher, and Byurakan took an active part in the construction of various SCA facilities, and many of them were provided with work, as well.
On the territory of the SCA, the staff of the ASRIRPM planted a lot of fruitful and ornamental trees, as a result of which the SCA became a very picturesque place.

The Historical Process

Since 1971, under the leadership of academician Paris Herouni, a set of manuals in the field of radiophysical measurements was created in Armenia. According to the author and chief designer, the following scientific, research and production units were included in the set:
1. Scientific Center of Aragats,
2. Center for office and research activities in Yerevan
3. “Alik” experimental plant in Yerevan.
In the scientific-production complex, created by Herouni was held scientific and technological research in the following areas: antenna theory and technology, radio astronomy, satellite communications, telecommunications, communication systems, control systems, telecommunications, and industrial services. In other related fields, experimental and design work was done, as well.
Under the leadership of Herouni, institute’s scientists were awarded several high government awards, as a result of scientific research, scientists/researchers have defended 10 doctoral and 35 Ph.D. theses. Also, the Chair of "Antenna Systems" was created at the Yerevan Polytechnic Institute after Karl Marx, etc.
The ASRIRPM owns a unique instrument, the name of which is known in the international scientific sphere as the Herouni radio-optical telescope ROT-54/2.6. It is a large parabolic antenna with a diameter of 54 meters, which is also combined with an optical telescope with a diameter of 2.6 meters. This system is the first and only one in the world. This Armenian antenna has several advantages compared to the characteristics of other big antennas in the world. ROT-54/2.6 application areas are Universe exploration and Deep Space Communications.
The ASRIRPM created and stored world's first antenna measurement standards recognized as state standards of the USSR.
Over the years the ASRIRPM has organized six international conferences with three different titles. Many famous specialists of the world have arrived in Armenia with their reports. ASRIRPM organizes educational and industrial practices for students from various leading universities in Moscow.
After the collapse of the USSR in 1991, under the conditions of independent Armenia, ASRIRPM lost major central budget funding and was re-registered in the RA Ministry of Economy as a JSC Research Radio-physics Institute.
11 standard complexes of antenna measurement were recognized as national standards of Armenia in 1995. The ROT-54/2.6 radiotelescope was recognized as a national value and was financed from the state budget in the period 1991-2011 with a fixed grant of about 20 million drams per year.
To preserve and develop antenna measurement standards, the RRI received an average of 60 million drams per year under the basic funding grant of the RA science Committee in the period 1991-2011.
During the period of independence of Armenia, due to the entrepreneurship abilities of Professor Paris Herouni and recognition by the world scientific community, the RRI has also implemented some business projects, including the financing of international structures. In particular, they have developed reflector antennas for satellite TV, designed and made the secondary standard for measurements for the UK Ministry of Defense, was a study developed for the French company "Thomson", the ground mounting and rotating bases for big antennas for American firm “ESCO” were made and sent, etc.
Radiotelescope ROT-54/2.6 in 2002 was registered as a historical and cultural value.
In the context of the energy crisis of 1991-1995 academicians, Herouni developed the idea of an alternative solar energy concentration new type power plant.
For many years, RRI has had a professional scientific Council approved by the RA General Supreme Commission, which awarded candidate and doctoral titles in the specialty «Antennas and microwave technologies». Educational and industrial practices were organized for students of Polytechnic University.

Specifications

The telescope is located at the RRI Aragats Scientific Centre in Orgov, Armenia. It is on Mount Aragats, at a height of.
The radio telescope has a diameter of. It is hemispherical, and fixed to the ground, with a movable secondary mirror with a diameter of. This provides a useful diameter of. It has a surface accuracy around 70/100 μm, giving an operating wavelength of 30-3mm, and was originally designed to observe down to 1 mm.
The optical telescope has a mirror, with a focal length.
Telescope never operates from the date of its implementation.

History

Construction took place between 1975 and 1985, first operating in 1986. It was not damaged by the 1988 Armenian earthquake, and was used for observations between 1987 and 1990.
It stopped being used around 1990, and in the mid-1990s a plan to restore the telescope to use it for astronomy was proposed. It was subsequently restructured in 1995-2010, with a new control computer, new feeds, and observations in collaboration with the Astronomical Society of Russia and the National Technical University of Athens.
From around 2012 onwards, moving the secondary mirror was not possible due to a defective control arm, with a restoration plan in 2018 so that the telescope can be used in the European VLBI Network.

From: Ir. MSc. C.G.M. van ‘t Klooster Voorhout, 27 Sept 2018 Antenna Specialist, formerly with European Space Agency (ESA) in Estec, Noordwijk, The Netherlands

ROT 54/2.6 This report presents observations made with pictures explaining a status. There is a main issue to be repaired and carefully inspected. Its feasibility of repair is a very important task to be realized as soon as possible. Only then, the sub-sequent tasks can be carried out, like new cabling, control and calibration of angular control. This report describes the importance of the repair in the contaxt of the telescope status. The details provided about ROT 54 are in the attachment. Many more observations and pictures are available. The main observation related to the cardan suspension is important here. The radio-telescope exploits a fixed spherical mirror and a secondary mirror, which is dimensioned such that a secondary focus is created in a location in which a radio frequency feed is mounted. The secondary mirror assembly with its supporting structure and 3 struts has a weight of 130 ton. The turning structure consists of the sub-reflector and total counterweight. The cardan bearing is 20 ton mounted on top of 3 supporting struts of each 12 ton. The struts are not straight but curved. This is beneficial for the allowable angular range. It has an electromagnetic benefit as well: the diffraction of the plane wave is spread out and does not form diffraction cones as severe as would be the case for a straight support. Mass figures are broken down, but it requires a verification. It is clear that there is a loading on the axes in the cardan suspension, which is heavy. It must be precise as it determines pointing of the beam.
The counter-ballast is usefully exploited with an optical telescope pointing into the same direction as the radio beam. It realized the first radio-optical telescope, explaining the short notation ROT 54/2.6 for the diameters of the main radio spherical mirror and the optical telescope mirror.
A particular important, main property of the spherical reflector is that it is fixed in the ground. No need for “a homologous designs” or “Finite Element Method” optimization for an accurate and light supporting construction as for a steerable main reflector. The main spherical reflector has a surface error which follows from a budget comprising mainly the error in the installation of the panels and the actual panel surface errors. The latter main reflector surface error is not subject to any deviation during a pointing operation of the radio telescope in principle.

The Main Spherical Reflector аnd Panel Configuration

The main-mirror is mounted on concrete, fixed in the ground. The radio optical telescope ROT 54/2.6 has a 54 m non-movable spherical reflector, consisting of some 3800 panels of ca 1 by 1 meter : some panels are larger. Panel mounting is on 4 tuning screws: panel errors at the rim are larger by a ratio /. All panels are made of aluminum-magnesium-zinc alloy. Eventually the absorption and emission coefficients for such material is needed in a thermal distortion analysis to assess gradients in temperatures, but this is for later. Steel mounting rods and panels are assumed to be well thermally conductive. Panels are milled towards a spherical shape with a final error at panel level of ±10μ. With a radius of 27 meter and a panel sizing of 1 by 1 meter, the deviation of a flat panel from a spherically milled panel is 27000000*, with η=1/54 or about 4.63 millimeter. With 180 panels in the upper rings there is an adaptation with such machining to circular shape. If it was a flat panel, the periodic deviation would equal 4.63/2 mm = 2.3 mm peak-peak across the panel and ~sqrt more in diagonal sense. It would be ε= 2.3/=1.328mm across.. It is a good first estimate order for rms, to be refined. For a minimum wavelength λmin = 20 * 1.328 it results that such a reflector would still be reasonably good at X-band, provided the panels are “perfectly mounted” perpendicular to the radius of main reflector. It shows perspective for higher bands !! In other words, a panel surface accuracy might be no issue below X-band, but the panel setting accuracy in terms of “rms” should not exceed a smaller value. How much? It depends. The error in the panel setting can be much smaller obviously, given a systematic required spherically shaped panel surface. Accordingly the reflector would allow operation up to millimeter wave regime. Given a secondary mirror of ~5 meter diameter and about ~±60° subtended angle, a small feed would be needed at centimeter wavelength below X-band resulting into a secondary pattern with a higher first side-lobe due to a predominant main aperture distribution with its maximum shifting towards the outer radius relative high first side-lobe near to – 10 a -15 dB. At low frequency accommodation has to be complied with. The panels have been precision milled with ±10 μ rms on a carousel-milling machine. All separate panels are mounted on a metal tube which is anchored into the concrete below the spherical main reflector. The distance between the 4 bolts is approximately 30 centimeter. Accordingly an error in the setting of a bolt of ±15μ would be magnified by a factor 2 to 3 at the panel edge to say ~±45μ. Accordingly an estimate can be made for a total rms surface error for the spherical mirror. A very suggestive observation is made from the reflection of the Sun into the reflector. Panels are machined in a systematic manner leaving observable rings on the panel surface. The sun reflection observed over a number of panels is indicative for a reasonable good panel setting, because of the regularity of the characteristic sun reflection over more panels, caused by the separate panels and additionally a diffraction behavior in the optical domain due to circular rings observed at panel level. An example is shown in Fig. 4. Slightly tilted panels could be found in this way.

The Sun reflected from spherical mirror

An Indicative regular pattern from panel to panel results with a small white band on each panel. The orientation of such band varies gradually from panel to panel and is a reasonable indication that even today the panel setting might well be acceptable for operation in the centimeter wavelength regime. Displacement of the bright location varies over time due to Sun movement or by walking around the main reflector rim… Obviously, a refined measurement approach has to confirm precise details, with a laser in the center of the half-sphere.

The sub reflector surface and secondary RF platform

The surface of the sub-reflector is shaped according to a precise required geometry and a location to be precise with respect to the main spherical reflector. The claim of inventing such correction has been made at the same time by Dr. P. M. Herouni and by specialists involved in the Arecibo reflector. With a perspective for utilization up into the millimeter wave regime, the ROT 54 radio telescope can be “electrically “ larger than the Arecibo antenna. The RF feeding point has to be located accurately with respect to the sub-reflector geometry. Being a low-gain RF feeding point, not much deviation in the RF coordinates is allowed. It has to be within about ±0.1 a ±0.2 λ. This needs verification. It would be as a crude estimation ±3mm a ±6 mm in X-band. It is clearly more demanding in the millimeter wave regime. It demonstrates the criticality of a precise cardan suspension needed and bending aspects as function of pointing for higher frequencies. Resulting deviations can be decomposed into statistical and systematic deviations, to be entered in calibration tables. This is for future work.

The sub-reflector assembly and its revival of control capability

It is noted that the total mass of the tripod support and movable mass is 71 ton, resting on 3 positioners as strut support locations with a total of 130 ton with a major loading of the south strut due to the off-zenith direction of the main axis of symmetry.

Behavior of the beam direction due to systematic gravity influence

The movement of the secondary reflector provides a beam direction by putting it into a desired direction ° for a main-beam into direction θ°, the angles measured with respect to the symmetry axis of the spherical reflector. The main symmetry axis is oriented towards a direction +25° to “South” leaving 15° with respect to the local zenith at 40°, the latitude of the location of the telescope. A beam pointing is available from 35° elevation to 85° elevation. All pointing deviations are due to bending and pointing errors of the movable structure of the sub-reflector. Such errors are in part systematic and can be calibrated. Given the mass and length of the pendulum-like structure this will be important. Given the off-zenith symmetry and loading of the “South” support strut, there will be a systematic behavior in the calibration table for angular errors due to bending. A useful area of 32 meter diameter is selected from the spherical reflector. With a secondary reflector correcting the spherical aberration an aperture of 32 meter with a blockage of ~6 meter diameter is available, to be illuminated by a spherical small feed over ~±α°, with α leaving a little bit illumination thus side-lobe control. Given the aperture blockage and α towards α=60°. Room for side-lobe control is limited an needs optimization. The first side-lobe is ~-15 dB. The effect on the pattern has been investigated already and particular choices of RF illuminating feeds are related obviously.

The RF front-end equipment

There has been no discussion about RF front-end equipment, neither IF and backend. This subject needs elaboration. Priority has been given to discussion of the main cardan suspension and its current status. Reception of a simple but accurate and systematically known beacon signal for propagation measurements might be a very suitable way to assess a large number of error contributions and subsequent assessment of impact or improvement. Reception of the Alfasat beacon at 19.7 GHz and 39.4 GHz could be a consideration at a later stage. Relevant background information about the propagation payload on Alfasat has been provided. Alfasat is positioned at 25° East in a slightly inclined orbit, thus virtually moving Nord-South daily over a couple of degrees.
A direct reception with a ROT 54 antenna pointed in a fixed position towards the satellite at 25° East would permit already 1 D pattern cuts, because the satellite is moving in a daily pattern in a systematic manner. Precise ephemeris data are provided on request. In this way a 1D Nord-South pattern could be monitored, nicely related to predominantly one axis in the cardan system. It would require initial assessment and provision of RF reception capability for the CW signals. Alfasat propagation payload is available for some time more in the upcoming year and possibly after. The CW carriers are rather stabile according to the information provided. Given a stabile 19.7 GHz CW signal, a direct reception by ROT 54 in comparison with a reception of the same signal with a much lower gain antenna can allow for holographic measurements. It would provide additional investigation capability and further fine tuning of the radio telescope.

Recapitulating

The spherical main reflector is in a very reasobale state, with perspective for further improvement -a- The current status of the control of the sub-reflector and telescope assembly is, that there is no control possible. The main control room is out of order. Cables have been cut and it is likely that a new cabling is required. Control capability and associated cabling requires detailed assessment and repair. -b- There has been no movement of the cardan suspension in the last 6 years. -c- A main issue is, that one side of the East-West axis inside the cardan housing has a defect control arm. This needs priority as without a repair there is no control of the East West axis possible. The current understanding is, that the lever for control of the angle of the latter axis is loose from the axis, with a bracket with broken bolts. How this has happened is unclear. -d- A careful inspection is needed. Just repairing the bracket alone is not a guarantee for a free and smooth and accurate movement of a secondary reflector assembly and eventual control. The latter movement is required as the angular pointing of the RF-beam depends on that movement. Only after inspection and repair of the bracket and careful mechanism investigation, linear actuators for moving the East-West axis might again be considered for movement. Obviously the control capability can only be considered after such a repair and inspection.
In summary: As there has not been any movement in the last 6 years, a lubrication of moving parts is important and might not directly guarantee accurate movement, given a status of materials and movable parts. Currently the East-West axis is blocked on purpose with welded brackets. It must be inspected the exact status of the mechanical parts within the cardan suspension, which carried the large mass of more than ~ 30 ton with two perpendicular axes and a central controllable tube to which on one side the sub-reflector assembly is mounted and on the other side the optical telescope. The importance of the latter is also understood from the main criticality of positioning the sub-reflector with RFplateau accurately within limits. The stability of the positioning has to be within limits dictated by the allowable error in the directivity. The latter positioning error is more critical if a stabile phase behavior has to be realized over an angular interval of movement, as could be the case for a tracking of a radio source in a VLBI observation. Such phase deviation if any should be calibrated out for a major part by using calibration tables, based on systematic deviations. The major ball-bearings have to be inspected. The major control capability for the heavy sub-reflector + optical telescope is directly important and related to deviations in precision and is more demanding obviously at higher frequency bands. Only after a repair of control bracket, inspection and preventive actions of all movable parts inside the cardan housing and attachment to struts, the behavior with angle can be derived in more detail. Accordingly an initial operation might preferably be at longer wavelength, for instance in X-band, for which there is also experience in observations. Possibly the 19.7 GHz beacon of Alfasat is very interesting and permitting analyses of various error sources with subsequent fine-tuning.
This short report has been written by: Ir. MSc. C.G.M. van ‘t Klooster Formerly Antenna Specialist European Space Agency, technical center Estec, Noordwijk, NL. Email: kvtklooster@gmail.com On request some details are given below C.G.M. van ‘t Klooster received an IR-degree in 1978 in Electrical Engineering from Eindhoven University and a MSc-degree in Space System Engineering in 2001 from Delft University. He is Lifetime IEEE Member and author or coauthor in more than 150 papers. In 1978 he joined Physics Laboratory TNO as antenna engineer with as topics ferrite phase shifters, waveguide based phased array antennas and planar near-field testing. In 1984 he joined European Space Agency in the Technical Directorate covering subjects like antennas for satellite projects including Meteosat, European Remote Sensing and other satellites. He was responsible in ESA R+D contract studies on slotted waveguide antennas, feeds and feed-arrays, SAR- and radiometer antennas in early and later phases, antenna testing aspects and various activities on and advancement of large deployable antennas for radio astronomy, remote sensing and telecommunication. He was awarded ESA Douglash Marsh fellowship in 1993, which he spent in Moscow at Lebedev Physical Institute in Radio-Astron space-VLBI project team. Achievements include initiation of dedicated new panel technology for ALMA with industry as a spinoff from X-ray telescope space technology and initiation of investigations with the institute JIVE into VLBI tracking of the Huygens probe during its landing on Titan. The work has been realised excellently by JIVE. After retirement in 2015 he continues part time with antenna activities in universities and some consultancies.

Technical parameters

Basic Data

General

Beam width
Temperature of the self-noise
Antenna aperture efficiency
Useful surface
Gain factor
The declinations of the observed sources
Video-guide №1
Video-guide №2
Load on the supports
Panels of the main radio reflector
Panels of the small reflector
Support tripod
Hanger of the small reflector
Mechanisms of radio-focus
Mechanisms of optical focus
Including:
These conventional, uncooled radiometers were manufactured in the All-union Scientific Research Institute of Radio measurements under the leadership of P. Herouni.

Storage of time

Underground pipe to drain water from the bowl:
Snow removing system: