Derby and District Astronomical Society

DDAS Observing Session - Saturday, 24th March 2012

Report by Claire Spencer

The skies looked set for a clear night of observing on Saturday 24th March 2012, after the previous weeks session was rained off to the default location of the Rose & Crown at Brailsford. Robert Seymour, who lives nearby to me, offered me a lift, as he was keen to try out his 5” refractor. The evening was a bit misty, but didn't look to bad as we set off with the 2 day old crescent moon, Venus and Jupiter dominating the West. Quite a few people arrived at the observatory during the course of the evening, and with four planets on show, they were in for a real treat.

The first object the society's 10” reflector looked at was the two day old crescent moon. There were many craters seen on the eastern terminator, caught by the rays of the rising sun. Jupiter came under the scrutiny of Robert's 5” refractor, and it did not disappoint. Masses of detail could be seen on the Jovian disc, with the cloud belts easily visible, the Northern Equatorial belt was very prominent, as well as the Galilean moons, of course.

Venus, being very high up in the West was the next object for the superb 5” to study. Venus presented a perfect half moon phase, but as usual with our closest neighbour, very little else could be seen on its dazzling white disc. Mars was very well placed in Leo, and had just passed opposition on the 3rd March. Although the disc was a little on the small side at just over 13 arc seconds, a lot of detail could still be seen, including the North polar cap and the dusky markings of the Mare Acidalium and the Tharsis region.

As Orion was still well placed, Robert's telescope was pressed into service to view the Orion Nebula, M42, below the famous three stars that make up the sword belt of the mythical hunter. The magnification was increased to have a close look at the Trapezium, which is a multiple star system of stars arranged in the shape of a lop sided square. I could see three stars, however the faintest eluded me, though other observers said that they could see all four.

Around 9pm, Robert announced that a satellite would shortly be visible. This was an iridium satellite, which briefly brightens as its highly reflective panels catch the sun's rays. Sure enough, bang on schedule, we saw a moving light which rapidly brightened, as it caught the sun's rays, and then just as quickly again faded. During the course of the evening, we saw a couple of other artificial satellites, slowly drifting their way through the constellations.

I then went into the main dome of the observatory, and as Saturn was now rising near to the bright star Spica in Virgo, the society's 10” reflector was turned to this most spectacular of planets. An excellent view was afforded of the planet and its glorious ring system. The largest Saturnian satellite, Titan, was easily visible. I also glimpsed the satellite Rhea, though others saw one more, possibly Dione. Some clouds belts were also observed on the surface on Saturn, though these were not as prominent as those on Jupiter. As the seeing was not the best, it was not possible to see the Cassini division in the rings, though I have seen it before through this telescope.

Mike Dumelow then suggested we look for some deep space objects, in this case the Leo triplet, which is a group of three galaxies about 35 million light years away in the constellation of Leo. The group consists of M65, M66 and NGC3628. I personally could only see two of the group, possibly M66 and NGC3628, as they are the groups two brightest objects at magnitudes 9.7 and 9.4 respectively. Other observers said that they could see all three.

All in all, a wonderful evening, despite hypothermia beginning to set in at about 11.30pm. Observing sessions are open to all interested, and if you can get along to one, you are sure to be made very welcome. Details of forthcoming observing sessions can be found on this website.

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