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Science and Technology Minister visits HartRAO - 2006/08/15

Minister of Science and Technology Mosibudi Mangena visited the Hartebeesthoek Radio Astronomy Observatory (HartRAO) on 2006 August 15. Astronomer Dr. Michael Gaylard acted as the guide for the tour around the facility, during which the Minister met many of the staff and students and learned about their work.

Staff astronomer Marion West acted as photographer for the visit, together with Linda Pretorius from Southern Science. The photo-essay below illustrates the tour.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
First stop was the 26-m radio telescope, where the Minister was able to take a close look at the 252 new high-accuracy surface panels that have greatly improved telescope performance.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Mike Gaylard describes the upgrades to the antenna since it was built in 1961 for a NASA Deep Space tracking station.

hart visit
Click on image for LARGE version. Credit: Linda Pretorius / Southern Science
The Minister inspects the antenna towering over him.

hart visit
Click on image for LARGE version. Credit: Linda Pretorius / Southern Science
Next stop was the Surface Upgrade Workshop, where the new antenna surface panels had been made, on the large "bed of bolts" seen here.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Antenna technician Pieter Stronkhorst explains how the panels were measured to check their accuracy after fabrication.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Mike reminds the Minister that it was Pieter Stronkhorst and Jacques Grobler who came to the rescue of an RFI measuring system used for SKA site testing and rebuilt it after it sustained damage on dirt roads in the Karoo.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Satellite Laser Ranger Manager Johan Bernhardt describes what the SLR is used for, while the 26-m telescope in the background goes back to monitoring the recovery of the Vela pulsar after its large glitch (sudden jump in rotation rate) two days earlier.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
SLR operator Sam Tshefu was tracking the Japanese satellite Ajisai as the Minister entered the SLR control van.

Ajisai is Japanese for Hydrangea. Satellite laser ranging to Ajisai provides high precision orbit determination and is used to improve the map of the Earth's gravity field. Launched in 1986, it is a 2.15 metre sphere covered with 1436 corner cube reflectors and 318 plane mirrors. It orbits at an altitude of 1490 km.

hart visit
Click on image for LARGE version. Credit: Linda Pretorius / Southern Science
The Minister was intrigued by the corner reflector, a duplicate of those mounted on the satellites tracked by the SLR.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
In post-track calibration of the SLR on a ground target the SLR operates in eye-safe low-power mode and the Minister was able to get a close up view of the laser transmitter and large telescope that receives the returning photons.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
The Minister is intrigued by the colourful poster created by a group of learners from Woodland Primary School who had made an overnight visit at the Observatory.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
A surprise visitor was Dr. Claire Flanagan, Director of the Johannesburg Planetarium. Claire established the pulsar research programme at HartRAO and continues to play an active part in it. The Vela pulsar is one that is closely monitored by the 26-m radio telescope. It typically glitches every few years, and one of the these events fortuitously occurred two days before the Ministers visit. In the absence overseas of pulsar observer Sarah Buchner, Claire stepped in and verified that the glitch detected by the automated software was real, and reduced the data to establish the glitch initial parameters. The telescope is currently monitoring the pulsar's recovery for twelve hours each day while the pulsar is above the horizon. Here Claire shows the Minister how the pulsar the latest data on the glitch.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
The Minister enjoyed hearing about the real life drama's involved in studying the glitches.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Moving from star death to star birth, Dr. Sharmila Goedhart told the Minister about research into star formation using masers as tracers of the environment in which it occurs. Here Sharmila describes the startling discovery that several of the methanol masers show periodic veriations - they tick like clocks, albeit with periods of months.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
The Minister enjoyed questioning Sharmila about the masers.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Sharmila illustrates how the collapse of dense molcular clouds triggers star formation.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
NASSP MSc student Christina Langa described her startling results obtained from daily monitoring of a methanol maser that had shown up in Sharmila's earlier fortnightly maser monitoring as "flickering" rapidly. Christina is registered at North-West University for her MSc.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
The Minister checks his understanding of what Christina has told him.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Mike demonstrates the geographical importance of the radio telescope at HartRAO in global networks of radio telescopes used both for astronomy and for geodetic research. The data from these telescopes are combined using the technique known as Very Long Baseline Interferometry (VLBI).

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
The Minister takes a close look at the images of the surface of the Moon taken by the Lunar Orbiter spacecraft in the runup to the Apollo Moon landings. At that time the station was part of the NASA Deep Space Network, receiving data from such spacecraft.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
In the Space Geodesy Laboratory, PhD student Joel Ondego Botai describes his investigation into the effects of water vapour on the accuracy of radio telescope positions determined from intercontinental VLBI campaigns. Joel is registered for his degree at Pretoria University.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
MSc student Sakia Madiseng discusses his investigation into potential new sites suitable for space geodetic instrumentation. Sakia is doing his MSc through the University of the Witwatersrand.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Attie Combrink has been using data from GPS base stations across southern Africa to measure the precipitable water vapour content of the atmosphere, and how it is changing over time, for his PhD. Attie recently submitted his thesis for examination at the University of Cape Town.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
The Minister asks about the implications of the changing water vapour pattern over southern Africa.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
For his PhD research Mojalefa Moeketsi is using GPS data to measure the total electron content of the ionosphere - the ionised upper part of the atmosphere - the correlation with the changing radiation from the Sun during the eleven year solar cycle. Mojalefa is registered for his degree with Rhodes University.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Sandile Ngcobo is developing a high-powered pulsed laser for his MSc research project. The aim is for this to be used in a new laser ranger to replace the ageing NASA MOBLAS-6 SLR. Sandile is currently based at the National Laser Centre at the CSIR, and is registered with the University of Stellenbosch for his degree.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Dr. Vasyl Suberlak described his work developing the proposed new laser ranger, which is intended to be capable of lunar laser ranging as well as ranging satellites in Earth orbit. Vasyl did his PhD in laser ranging in the Ukraine.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Moving on to the electronic workshop, Paul Prozesky demonstrated the "hot spare" electric motor for the 26-m radio telescope. The replacement of the original hydraulic motors by pairs of electric motors on each axis in 1998 provided much improved pointing precision and control.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Engineer Keith Jones describes the new 22-GHz / 1.3-cm wavelength receiver under test in the microwave laboratory. This is designed to capitalise on the much extended wavelength range over which the 26-m telescope can operate since the installation of the high-precision, solid main surface panels between 2000 and 2004.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Paul Prozesky in the new digital electronics laboratory describes how we will be replacing analogue electronics with digital systems using FPGA's. This technology is being implemented in collaboration with the team developing the Karoo Array Telescope (KAT).

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Richard Moralo demonstrates the skills he is gaining in the mechanical workshop. Here is using the milling machine to cut an adaptor plate to permit the mounting of a chuck on the machine.

hart visit
Click on image for LARGE version. Credit: Linda Pretorius / Southern Science
Outside the Visitors Centre, Mike showed how a standard satellite dish can also function as a small radio telescope, and easily detects the radio emission from the Sun.

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
More surprisingly perhaps, a satellite dish also detects microwave emission from the human body!

hart visit
Click on image for LARGE version. Credit: Linda Pretorius / Southern Science
The Minister saw the Science Awareness team in action, with two busloads of learners from Ikaneng Combined School visiting the observatory. Here Anacletta Koloko is helping learners discover the mysteries of angular momentum on a turntable.

hart visit
Click on image for LARGE version. Credit: Linda Pretorius / Southern Science
How much would one weigh on the planet Jupiter? The Minister finds out!

hart visit
Click on image for LARGE version. Credit: Marion West / HartRAO
Sam Rametse shows learners what happens to marshmallows when they are put in a vacuum chamber, using equipment developed by MEng student Benjamin Klein.

hart visit
Click on image for LARGE version. Credit: Linda Pretorius / Southern Science
The visit ended with the handover of a brochure of background information on the Observatory.