Orwell Astronomical Society (Ipswich)
10-11 May 1980
Observations by M Barriskill, R Townsend and R Robertson at Orwell Park Observatory, using the 26 cm refractor, 21:00-03:30 UT, 10-11 May 1980.
- Planets. Mike Barriskill found Venus, and we noted it to have a pronounced crescent phase. We also observed Mars, which was gibbous, but could discern little detail. Jupiter showed several belts, and the Galilean satellites were easily visible. We skipped observing Saturn in favour of other objects.
- Galaxy M51. With magnification x156 the galaxy showed great detail. The nucleus was surrounded by a fainter disk of light, the Population I regions. There was a hint of two spiral arms within these regions. A third, much fainter arm extended from M51 to the companion galaxy, NGC 5195. The companion itself did not appear as a round blob of light but rather more like a rose seen sideways on.
- Markarian 421 (a BL Lacerta Object). We found this object with no difficulty. (I have tracked it down previously with my own telescope.) It lies close to the star 51 Ursae Majoris, which is shown in Norton's Star Atlas. Markarian 421 appears as a point of light of magnitude 13.
- Quasar 3C273. Shining at magnitude 12.5-13.0, this is probably the most distant object accessible to most amateur astronomers, at a distance of 3 billion light years. It took considerable effort to identify the quasar and, in fact, I would have been unable to identify it were it not for the finder chart supplied by David Childs of Luton Astronomy Society together with Atlas Coeli which showed some of the field stars surrounding it. The quasar lies in a curious pattern of stars not unlike a miniature version of the "W" of Cassiopeia. The star at the middle of the "W" is much more difficult to see than the quasar which lies next to it. Stars from the identification field were visible down to magnitude 14.
- Globular cluster M13. This is a spectacular object in any instrument. It comprises thousands of stars in a dense ball and we could discern hundreds of them, sprawling a long way from the centre of the cluster, to greater distances than I had previously seen.
- Pluto. Mike Barriskill undertook the arduous task of attempting to identify Pluto. After a long search with the aid of the finder diagram in the BAA Handbook, he found the neighbourhood of the planet, but none of us could be sure which object in the neighbourhood was Pluto itself! There were several faint objects and dots of light which might have been the planet.
- Planetary Nebula M57. This is a pleasing object which was well seen in the 26 cm refractor. We easily saw the centre as being darker than the surrounding ring.
- Planetary Nebula NGC 6210. This object presented a small but bright disk of light. It is blue in colour and it would be very rewarding to compare it with others of the same kind, such as NGC 6543 or NGC 7662. The object needs a high magnification to bring it out well. Under low magnification, the inexperienced eye could mistake it for a star.
- Barnard's Star. This object is well worth looking for, as it is the nearest interstellar object visible from the UK, lying only six light years away and moving at a speed of 10.3 arcsec per annum. It proved much easier to find than I had expected, using a finder chart supplied by the Royal Greenwich Observatory.