Upcoming Astronomical Events

View the Sky at Night chart for May (39KB MS Word doc)

The Sky at 11pm on 15th May 2012

Those keen to observe the constellations in May will have to stay up quite late as, by the end of the month, the Sun sets at 9.50pm and the sky will only be reasonably dark an hour later.

The constellation Virgo is one the zodiacal constellations. It will be quite low in the south during May and will be made more prominent by the presence of Saturn. Only about five degrees from Saturn is Spica, the brightest star in Virgo. Spica is a blue giant binary star 260 light years distant. It has a much higher surface temperature than our Sun and the larger of the Spica pair is seven times the diameter of the Sun. Using the fact that the Temple to Menat at Thebes was aligned with Spica in 3200 BC, Hipparchus (190 – 120 BC) discovered that the star’s position had changed in the intervening 3,000 years. He concluded that the equinoxes were moving through the zodiac at more than one degree each century.

Concentrated in Virgo is the Virgo cluster of galaxies of which there are about 1300 members. The centre of these galaxies is about 54 million light years distant and they form part of the Virgo supercluster of which our own Milky Way galaxy is an outlying member. Many of the brighter galaxies were discovered in the late 18th century and were included in the catalogue of Charles Messier, the comet hunter, so that he would not confuse the numerous faint and diffuse objects in the area with possible comets. A number of these brighter galaxies can be seen with a fairly small telescope on a dark, moonless night.

Looking upwards from Virgo is a distinctly bright, slightly orange coloured star. This is Arcturus, the brightest star in the ancient constellation Boötes. Boötes represents a herdsman or ploughman and is shaped rather like a kite. Arcturus is an older star than our Sun and may well represent what our Sun will become in several billions of years as more of its hydrogen is converted to helium. Arcturus, at 37 light years distant, is moving at a speed of 122 km/second and at this speed will be lost to the unaided eye in a relatively short time span of several million years.

Mercury is not well placed for observation during May.

Venus continues to be very bright towards the north-west during the first part of the month but will gradually be overtaken by the brightening evening sky.

Mars is in Leo during May and will be seen in the south-west for most of the evening.

Jupiter is too close to the Sun to be seen this month.

Saturn, in Virgo, will be well placed in May being due south at 10pm on the 15th.

The Moon will be full on the 6th, at last quarter on the 12th, new on the 20th and at first quarter on 28th.

Mills Observatory will be open every Tuesday to Friday, 11am to 5pm, closed on Mondays, and on Saturdays and Sundays from 12.30pm to 4pm. There will be a talk about the May sky and planetarium show on Wednesday 9th May at 2pm. Admission is £1 for adults and 50p for children. Please phone 01382 435967 to book as places for each show are limited.

Dundee Astronomical Society continue their summer talks on Sunday 13th May at 1.30pm. The talks are designed mainly for beginners to astronomy and visitors to Mills are welcome to attend. Admission is free. The talk this month will advise on telescopes and binoculars for astronomical observation and will be given by Bill Samson.

Visitors arriving by car should use the Glamis Road entrance to Balgay Park.

The Mills website can be located at www.dundeecity.gov.uk/mills

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