the return to service of the hartrao 26m telescope michael gaylard hartrao

The Return to Service of the HartRAO 26m Telescope

Michael GaylardHartRAO

South polar shaft bearing failed 2008 October 03

Diagram of NASA antenna similar to HartRAO's

A-frame to support telescope during bearing replacement

HartRAO 26m telescope repair - pouring foundations for A-frame April 19

Components at Tass Engineering, Johannesburg May 26

Ludwig Combrinck measuring the polar shaft position May 27

Placing the A-frame box-beam on the concrete bases June 10

Preparing the A-frame legs June 18

First A-frame leg hanging from collar around polar shaftJune 21

Bracing the hour angle gear wheelJune 23

Last A-frame leg installedJune 24

Inserting the pin locking the A-frame leg to the box-beam June 24

Welding A-frame base to box-beam June 29

200-ton hydraulic jack lifts the telescope June 30

Polar shaft end cap puller in place July 01

Removing the polar shaft end capJuly 02

Failed bearing exposed July 02

Extracting fragments of shattered bearing July 02

Arc-gouging to extract remains of bearing July 06

Preparing polar shaft end cap for re-installation July 13

The new bearing is in July 15

Re-installing the polar shaft end cap July 15

Removing the A-frame July 16

The telescope drives West for the first time 2010 July 20

Testing the limits July 22

First light – testing the telescope pointingJuly 22

First pulsar observation – Vela pulsar July 23

First spectroscopy – water vapour in Orion July 23

26m and 15m (XDM) – both observing the Vela pulsar July 23

Vela pulsar glitches after 4 years – on July 31 at 21h 15m SASTdiscovered by 15m XDM then 26m

Sarah Buchner

See Astronomers Telegram 2768

Interacting Binary star Circinus X-1radio flares

See Astronomers Telegram 2699

First VLBI after repairICRF astrometry Aug 11

First target of opportunity e-VLBI with the EVN, Sep 30

MAXI J1659-152Zsolt ParagiATEL 2906

e-VLBI to Europeat 1024 Mbps – Nov 23

Target of Opportunity – Crab Pulsar

e-VLBI to Australiaat 512 Mbps – Nov 24

Jonathan Quick

26m Telescope Repair – Key Players and timeline

National Research Foundation – President Albert van Jaarsveld approves motivating the repair, 2009 July 22

Department of Science and Technology – Minister Naledi Pandor obtains funds for the repair

GD Satcom (US) – prime contractors - Tom McClellanStratosat Datacom (SA) – local contractors – Gerhard BothaTass Engineering (SA) – heavy engineeringHartRAO – Pieter Stronkhorst, Antennas and special projectsFirst post-repair observation – 2010 July 22First post-repair VLBI – 2010 August 11 - Jonathan Quick, VLBI Operations Manager