Orwell Astronomical Society (Ipswich)
Solar Total Eclipse, 29 March 2006
Once again Explorers Tours did us proud! On this occasion, they mounted a trip for 780 people to reach a spot in the middle of the Libyan Sahara desert, some 500 km south east of Benghazi, to view the eclipse of 29 March 2006. Travelling in a convoy comprising 15 coaches, a petrol tanker, two ambulances and a police escort, we set off at 2.00am allowing what we thought would be ample time for the journey. However, we hadn't allowed for the time to fill each coach at the one petrol pump open at that time of the morning nor the numerous stops to allow slow coaches (!) to catch up. Ten hours later we arrived at the appointed desert site, but so had a large number of locals, so we travelled a further few kilometres, resulting in a mutiny as there was only 10 minutes before first contact, not enough time for the serious photographers in the party to set up their equipment.
However the site, when we finally arrived, was excellent, an infinite expanse of light coloured sand. We set up our instruments; I was using the usual ancient but good Hi8 video camera with lens modifications. Up came second contact. We had been briefed to look out for shadow bands and especially nice Bailey's Beads on the points of second and third contact. (Shadow bands are ripple shadow effects thought to be produced by differing air densities brought about by rapid temperature differentials just before and just after totality. Baily's Beads are formed by sunlight reaching the earth through deep valleys on the lunar limb.) Sure enough, the shadow band effects were spectacular, better than I have ever seen before. Although I did forget to look out for them after the total phase, many people saw them then too.
As we were very close to the centre line of eclipse, we enjoyed about 4 minutes and 2 seconds of totality. This provided enough time to look about at other things happening, such as the level of darkness immediately above us contrasting with the bright ring of sky around the horizon. Various planets were plain to see during totality: Mercury (difficult), Venus (blindingly obvious) and Mars. More importantly, there was plenty of time to study the Sun's corona with binoculars, which can be a dodgy occupation when, as in Australia, there was only 27 seconds safe time. There were some really nice little flares visible during the first and last moments of eclipse. The chromosphere was also clearly visible. This is the outer layer of the Sun's surface, not usually visible because of the much brighter, underlying photosphere.
Many locals were wandering around the site and, much more annoyingly, driving, creating clouds of dust. They were very friendly, chatting and taking photographs of us including, unfortunately, using flash photography during the total phase, spoiling many observers' shots.
All too soon the spectacle was over and we were taken to the support site, where some groups had a tent city set up in the desert. There was a toilet block and an enterprising individual had brought a lorry load of camels for us. Whether we were meant to ride the animals or eat them was unclear, but they did look cute sitting in the back of an open-top truck. Then came the trip home back to the boat. The words "never ending journey" spring to mind: ten hours in a coach totally devoid of any legroom. I had difficulty walking for the rest of the trip!
See Fred Espenak's eclipse web site eclipse.gsfc.nasa.gov/eclipse.html.
Paul Whiting, FRAS