Astronomy Benalla Dark Sky Site Report - Saturday 11th December 2010
Reports - 2010
Our December night viewing was held at the Benalla Racecourse Cricket Ground venue in association with
a celebratory Christmas Starbeque.
On arriving at the venue with the Sun still well above the horizon, our new Personal Solar Telescope (PST)
took precedence prior to unloading and setting up the portable gas barbeque. This enabled any of the early
arrivals to safely view the Sun and its two gigantic sunspots. These sunspots, many times larger than the
Earth, are changing position as the Sun rotates.
An excellent roll up of members and friends thoroughly enjoyed the barbeque which was finished off with a
specially baked Christmas cake (per Gwen Cheetham) prior to moving out on to the oval to set up the
telescopes. As the dusk turned to darkness, carloads of visitors began to arrive and wandered out to view
the 3-day-old, thin crescent Moon as it peeped out between the clouds. The club’s new 102 mm diameter
refractor telescope saw it’s ‘first light’ and was christened by Anne, Jan & Denis by zooming in on the
Moon’s cratered surface and the Sea of Serenity near where the spacecraft Apollo 17, the last manned
moon flight, set down just over 36 years ago.
The clouds continued to disperse and the sky opened up to reveal the bright planet Jupiter and this was
the next goal for the five telescopes to aim at. By increasing the magnification the four Galilean moons Io,
Europa, Ganymede & Callisto all in line brought excited gasps from the visitors. Galileo first discovered
these moons just over 400 years ago, and probably uttered something similar. A young visitor who brought
along his newly purchased telescope was assisted on how to set it up and accurately point it at the desired
objects by President Rupe Cheetham.
As the night wore on the Constellations of Orion (The Hunter) and Taurus (The Bull) came into view and
also allowed Wayne’s big Dobsonian reflector to hone in on the brilliant young star cluster, The Trapezium,
highlighting the M42 nebula in the handle of the well known ‘saucepan’, some 1,350 light years away. This
was followed up by views of the famous Pleiades open star cluster, also known as the Seven Sisters and
catalogued by Charles Messier as M45. These seven stars are relatively close at 440 light years, can be
seen by the naked eye - views were enhanced by Anne’s 10 x 50 astronomical binoculars. These close,
major stars are hot, blue and extremely luminous, and helped to create a ‘cosmic ladder’ for distance, used
to obtain distances to other star clusters and to galaxies. The pale blue disc of Uranus, very close to
Jupiter this year, was the last major body to be viewed.
Unfortunately a thick cloud front came across at 10-00pm forcing an end to a good and promising viewing
night. Nevertheless, all the visitors had seen their share of several celestial delights.