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Geared to turn photons into paper.

When visiting the Sutherland Observatory you are astounded by the sheer number of domes and hosted experiments populating the plateau today. The three domes present during the official opening of the Observatory on 15 March 1973 have since grown to 20. Although the number of hosted experiments have only increased from two to six, they got much more sophisticated. This article gives and overview of the facilities on the Sutherland hilltop today.

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If we start with the three original domes which housed the 0.5-m (20-inch), 0.75-m geared to turn photons into paper (30-inch) and 1-m (40-inch) telescopes respectively. The 20-inch (as it is mostly still referred to), made by Boller & Chivens, was moved here from the Republic Observatory in Johannesburg where is was officially dedicated on 19 April 1968. The Republic Observatory closed down when the SAAO (South African Astronomical Observatory) formed. Only six of the 20 telescopes on the hilltop are manned of which the 20-inch is one. It is fitted with a dedicated photometer and is still well subscribed.

The date on the 30-inch telescope's nameplate is 1974, indicating that it was the newest of the original three telescopes. The telescope was made by Grubb Parsons, England but its mounting is older, dating from 1964. The mounting was moved from the former Royal Observatory in Cape Town where it carried the MRM (Multiple Refractor Mount), three photographic refractors which could make simultaneous exposures in three colours. The 30-inch was mounted in the counterweight position. The MRM-tubes were removed in the early 1990s and replaced by a proper counterweight. After removal of the lenses, the tubes were donated to the Sutherland town where they are still on display in front of the Information Centre. The 30inch is also manned and can be fitted with a suite of instruments.

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The last of the original trio, the 40-inch or 1-m was built by Grubb Parsons in 1962 and officially dedicated as the Elizabeth Telescope (after Queen Elizabeth) on 1 May 1964 at the Royal Observatory, Cape Town. It is also manned and is still in good demand with a suite of instruments available.

After the closure of the Radcliffe Observatory near Pretoria in 1974, the 1.9-m (74inch) Grubb Parsons reflector was moved to Sutherland. This is the oldest telescope at SAAO, Sutherland, built in 1938, and has been kept competitive by constantly upgrading it with new technology. Together with its twin in Egypt (which has not been operational at times), they were the largest telescopes in Africa until SALT was opened in 2005. Quite a number of instruments are available for this telescope and it is fully subscribed by local and overseas observers alike.

The IRSF (Infrared Survey Facility), a joint project between The School of Science at the Nagoya University in Japan and SAAO was officially opened on 15 November 2000. The telescope, built by Nisimura, with its mirror diameter of 1.4m, is the third largest telescope on site, but its dome is only similar in size to the 30-inch (0.75m). The reason being its modern AltAz mounting and fast optics. Its dedicated instrument called SIRIUS (Simultaneous3 colour InfraRed Imager for Unbiased Survey) observe objects simultaneously in three infrared wavelengths and can also be configured for polartimetery. It is mostly used by Japanese observers, but not exclusively. The main survey targets are the Magellanic Clouds and the Galactic Centre.

The last of the manned telescopes is SALT (Southern African Large Telescope). SALT was officially opened in November 2005. Its main mirror is 11m in diameter, making it the largest single optical telescope in the southern hemisphere. Two instruments are present at prime focus, a science camera and a sophisticated spectrograph. SALT is a section 21 non-profit making company, belonging it shareholders which include 13 international partners spread over seven countries. Telescope time is shared pro-rata amongst its partners according to their contribution to the project. SAAO has been contracted to operate and maintain the facility.

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The rest of the telescopes on site are all robotic. The oldest robotic facility in Sutherland is BiSON (Birmingham Solar-Oscillations Network), built in 1989. It predates the Internet, so the data it gathered was originally sent back to the UK on floppy disks by post. It was the second of a worldwide network of six remote, ground-based telescopes providing round-the-clock monitoring of the globally coherent, core-penetrating modes of oscillation of the Sun--so-called helioseismology. BiSON is operated by the High Resolution Optical Spectroscopy group of the School of Physics and Astronomy at the University of Birmingham, UK.

Two identical domes were erected at the time when BiSON was built, the other destined for the ACT (Alan Cousins Telescope). Its purpose is described in its original name, the APT (The Automatic Photometric Telescope) which was later renamed in honour of the life and work of Dr A.W.J. Cousins, in recognition of his long interest in accurate photometry. This was a joint project between SAAO, UCT and UNISA. The 0.75m compact split-ring equatorial telescope was built in the SAAO workshops and completed in January 1993. The mirror was figured by the CSIR's Optical group in Pretoria. Due a number of holdups, the telescope was finally only commissioned in mid-2000. It since experienced problems and is currently being refurbished with a number of systems being upgraded.

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In April 2002 the first clamshell dome appeared, housing YSTAR (Yonsei Survey Telescopes for Astronomical Research). This project was run by the Yonsei University, Korea to monitor variable stars and other transient events. It sported an ultra-compact 0.5-m aperture Cassegrain telescope fitted with a CCD camera. This facility was de-commissioned at end of June 2011.

Another clamshell dome has been part of the Sutherland skyline since 2003 but the MONET-South telescope was only installed there in September 2008. Although the name sounds French, it is an acronym for MOnitoring NEtwork of Telescopes), operated by the Georg-August-Universitat Gottingen, Germany. The project consists of a network of two 1.2m telescopes with its northern equivalent at the McDonald Observatory in Texas, USA. A science-grade CCD camera is the detector. Apart from doing robotic observations, the telescope can also be used for remote observing. A large fraction of the observing time is available to schools as part of the Alfried Krupp von Bohlen und Halbach Foundation's "Astronomie & Internet" project for schools. As reported in MNASSA Vol 69 Nos 11 & 12 December 2010, the Hermanus Centre is actively participating in this, involving local schools.

Another pair of identical clamshell domes mushroomed recently (2011) when a Polish group established two 0.5-metre robotic telescopes as part of a global network (Australia, Africa, South America) dubbed Project Solaris. Science-grade CCD cameras again are the instrument packages. The project has two main goals. Firstly to detect circumbinary planets around a sample of up to 350 eclipsing binary stars using eclipse timing and precision radial velocities. Secondly to characterize the binary stars with an unprecedented precision to test the stellar structure and evolution models.

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Another program searching for exoplanets since 2006 is SuperWASP-South, housed in a roll-off roof observatory. As the name suggest, it has a northern hemisphere twin, located on the island of La Palma. Both observatories consist of eight wide-angle CCD cameras that simultaneously monitor the sky for planetary transit events. SuperWASP is the UK's leading extra-solar planet detection program comprising of a consortium of eight academic institutions which include Cambridge University, the Instituto de Astrofisica de Canarias, the Isaac Newton Group of telescopes, Keele University, Leicester University, the Open University, Queen's University Belfast and St. Andrew's University.

There is a third exoplanet search program located in Sutherland, called KELT-South, housed in a roll-off roof observatory which started operating in September 2008. KELT is an acronym for Kilodegree Extremely Little Telescope because the "telescope" is simply an equatorially mounted CCD camera fitted with a lens of 4.5cm aperture. It too has a northern hemisphere twin, deployed in Arizona. The purpose of the project is to discover transiting extrasolar planets around stars in the brightness range of 8 < V < 10 mag. The telescope is owned and operated by Vanderbilt University, Nashville, Tennessee.

Another roll-off roof observatory, built in 2007 next to the IRSF, was dubbed the Sumi-hut, (named for the Sumitomo Foundation that supplied funding for the project). It houses the 220mm aperture WFCT II (Wide Field Cryogenic Telescope II), a special infra-red telescope whose interior, including detector and optics, is under vacuum and cooled to cryogenic temperatures. Like the IRSF, it too is a project of Nagoya University, Japan.

The last two observatories both house site testing gear. A roll-off roof shelter, commonly know as the Ossewa (since it resembles an Ox Wagon when open) was built in 1994 housing a DIMM (Differential Image Motion Monitor) system for doing seeing measurements. This system was used as a reference while a second portable DIMM was operated from three positions on site to decide on the final location of SALT. Dr Timothy Pickering recently upgraded the facility to a MASSDIMM system, which is two instruments in one. MASS (Multi Aperture Scintillation Sensing) measures how different layers of the atmosphere contribute to the seeing for altitudes ranging from 300 m to 32 km. At the heart of the modernisation is TimDIMM, the software he developed to run the camera and analyse the data from it. The dome has also been motorised, allowing full remote operation. Real-time seeing data is now published on the SALT weather page.

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For one year during 2010, a SLODAR (SLOpe Detection And Ranging) optical turbulence monitor, developed at Durham University, UK, was erected near SALT and run in parallel with MASS-DIMM to cross-calibrate it. SLODAR provides real-time measurements of the atmospheric turbulence strength, altitude and velocity. The telescope has since been returned but the clamshell canvas shelter surrounded by a blue protective shadow-net windbreak is sill there today.

At the site of the LCOGT (Las Cumbres Observatory Global Telescope) network all the foundations and three domes, each destined to house a 1-m telescope, have been completed. The next phase of installing equipment is planned for August. Apart for the scientific aims for the 1-m telescopes, a wider audience is destined to use the other two clamshell domes which will eventually contain four 0.4-m telescopes.

Hosted Experiments

A scientific facility like the Observatory, located on a remote site like this, but with an infrastructure of power, water, internet, etc and manned with technical backup is very attractive to house experiments.

When the Observatory opened in 1973, two experiments were hosted on site. The Ainglow building housed both the Airglow experiment, measuring the atmospheric glow as well as the photographic recording equipment of a seismograph, run by the South African Geological Survey. The seismometer instrument is located in an underground vault, with its pier built on the bedrock. The airglow experiment was terminated after a few years while the seismometer still exists today, but in a much more modern format and managed differently.

The Seismograph is now part of Project IDA (International Deployment of Accelerometers) is a global network of broadband and very long period seismometers operated by the Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics (IGPP), Scripps Institution of Oceanography (SIO), University of California, San Diego (UCSD). Project IDA is an element of the IRIS Global Seismographic Network (GSN) supported by the Cecil and Ida Green Foundation for the Earth Sciences and the National Science Foundation. There are currently 40 broadband stations deployed worldwide. A big satellite dish next to the Sutherland vault supplies seismic data to the CTBT (Comprehensive Nuclear-Test-Ban Treaty) network which monitors nuclear explosions everywhere; on the Earth's surface, in the atmosphere, underwater and underground.

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Geophysical Facilities comprise SAGOS (South African Geodynamic Observatory), a co-operative agreement between the National Research Foundation (NRF), South Africa and the GeoForschungs-Zentrum Potsdam (GFZ), Germany. The station was built in 1999 and is equipped with a Superconducting Gravtimeter, a PRARE (Precise Range and Range-rate Equipment) Station and a GPS (Global Positioning System) Receiver as part of the International GPS Service for Geodynamics.

A second high quality GPS receiver is shared between the South African Department of Land Affairs and HartRAO's Space Geodesy programme as part of the International GPS Service (IGS). The latter system consists of about 125 satellite tracking stations, three Data Centres and seven Analysis Centres worldwide. The GPS data sets are used to generate GPS satellite ephemerides, Earth rotation parameters, IGS tracking station coordinates and velocities, GPS satellite and IGS tracking station clock information.

SANSA Space Science (formerly Hermanus Magnetic Observatory) has been operating a pulsation magnetometer from Sutherland for the last ten years. This is located in a cluster of vaults just below the surface, to the south of site, far enough away from everything so as not to be affected by any electromagnetic interference.

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Sprite is a global network (Scotland, California, Australia and South Africa) of data loggers and magnetic coils to measure, count and map the location of Sprite lightning (Transient Luminous Events). Each system consists of a data logger about the size of a briefcase and two magnetic field sensors. It runs off a 12V battery and connects to the internet. The experiment is run by the Department of Electronic and Electrical Engineering, University of Bath, UK. The Sutherland installation is located east of the 74-inch dome.

In one corner of the Airglow building (currently being used as the Electronics lab) is a computer connected to a VLF (Very Low Frequency) antenna outside. This is an experiment by Dr Andrew Collier, Physicist at the Waves and Space Plasmas Group, SANSA and the Space Physics Research Institute, University of KwaZulu-Natal, Durban.
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Author:Koorts, Willie
Publication:Monthly Notes of the Astronomical Society of Southern Africa
Date:Jun 1, 2012
Words:2290
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