Introduction to Astronomy – Week 2
Week 2 of the Introduction to Astronomy course was presented by Peter Howell entitled “Sunshine and Green Cheese”. Peters talk covered details on the Moon and the Sun.
Peter started by talking about the Sun, and gave a great talk on every aspect of the Sun, including information that sunspots appear in magnetic pairs. Also that charged particles from the Sun give rise to the Northern and Southern lights. It was also interesting to hear that a supernova 10 billion years ago produced gold.
Peter then discussed in depth about the various stages of the moon, and why First Quarter is called what it is, and he pointed out all the Apollo landing sites on the Moon. Peter also showed images of interesting areas of the Moon to look at, including Schroter’s Valley, Rupes Recta fault line and the Hadley Rille.
Peter handed out paper moon maps as well as sheets in order to allow you to construct your own sun dial (diptisch dial). It was very interesting to find out that the equation of time varies heavily between summer and winter, indicating that the Earth rotates at different speeds through out the year.
After the talk was over and we had tea, we ventured out to the Institute of Astronomy’s outside Observatory building which houses the library. The library room holds a number of very old and interesting astronomy and cosmology books together with the latest astronomy journals and magazines.
Whilst in the library room we managed to see slides taken between 1945 and 1985 by the Schmidt telescope.
The Schmidt instrument was built in 1952 by Grubb-Parsons of Newcastle-upon-Tyne and replaced an older telescope in the existing dome, which had been made by T. Cooke & Sons Ltd. of London & York at the time of the move of the Solar Physics Observatory from South Kensington to Cambridge.
It is a `Classical Schmidt’ – the simplest and most efficient form of the ingenious wide-field camera invented in 1930 by Bernhard Schmidt of Hamburg Observatory. Light from the sky falls upon a 61 cm (24-inch) mirror with a spherical reflecting surface, at the bottom of the tube. It is reflected to a focus in the centre of the tube and half-way up it, 163 cm (64 inches) from the primary mirror. At the focus a photographic plate P 15 cm (6 inches) in diameter, which must be bent to fit a curved surface, records the star images in an area of sky 5 degrees in diameter. (The full Moon is half a degree in diameter.)
Below are some images I took with my mobile phone that were produced by the Schmidt Camera of Halley’s Comet in 1986 and another part of the cosmos.