With the mesh laying done and dusted, today we turned our focus to tack welding. For this part of the job we make several welds along where the three sheets of mesh meet to create a single conductive sheet.
Welding in the bush means taking lots of precautions to avoid fires, so behind one of our vehicles we tow a “Fire Tender”, a big water tank on a trailer connected to a hose and a motor to drive a pump and provide water pressure. Should a fire break out the first course of action is to stamp it out or throw a shovel of sand over it, failing this we turn to the Fire Tender trailer and douse it with water. Fortunately the day went smoothly and any smouldering tufts of grass under the weld points were quickly taken care of with a boot.
Once we got underway we quickly fell into a streamlined routine with two of us moving the heavy welding equipment back and forth and the other two crouching and shuffling along each tile to weld the sheets together. By days end we’d completed 62 sites including the entire core. This puts us beyond the half way mark already as several of the 128 tile sites cannot be laid as they are located on “trenches” being used by vehicles for access to the different areas of the MRO.
This morning while we were assembling the welding equipment and collecting the Fire Tender trailer I had a chance to get up close to CSIRO’s Australian SKA Pathfinder (ASKAP) antennas, the beginnings of a very impressive “next generation” radio telescope. I’ve been talking about ASKAP as part of my work for the past half a dozen years, so to actually get to see it in person and wander around it is very exciting.
Like the Murchison Widefield Array radio telescope we’re here to work on, ASKAP is another of the three official precursors to the Square Kilometre Array (SKA). The third is South Africa’s MeerKAT radio telescope.
ASKAP is being led by CSIRO working with leading scientists and engineers in The Netherlands, Canada and the USA, as well as people from other Australian universities. The telescope is expected to be complete in 2013, but has already started working with some of the antennas.
When completed ASKAP will comprise of thirty-six dish-shaped radio antennas. Right now all 36 antennas are on the ground awaiting the complex electronics that will link them together and allow them to observe the radio sky as one.
Each dish is 3 stories high and 12m in diameter and unlike other “dish” radio telescopes which can only move in two directions, up and down and side to side, ASKAP antennas can also rotate around, something which has never been done before.
Once its fully operational ASKAP will be used to discover new objects and help answer questions about how galaxies formed and how magnetism in the Universe came about. Even though its still being built the first 5 years of observing time is already booked up, such is the keen interest by astronomers eager to take advantage of this new instrument.