Thu, 24. December 2009
Astronomy in the UK
The first thing I noticed is that from Sydney, we have access to a much larger proportion of the entire sky than observers in England. At 34° S, we can (theoretically) see all the sky from 90° South as far as declination 56° North. In England, at a latitude of 52° N, one could only see from 90° North as far as declination 38° South, leaving a very much larger area of the sky unseen. Some might say the better areas. The converse of this is that a greater proportion of the sky is circumpolar in England, with all objects between declination 90° N and 52° N theoretically visible all the year round, making the sky much easier to familiarise oneself with.
There are eighty-eight constellations in the entire celestial sphere and it caught me by surprise to find out that there are only two of them that are fully below the theoretical horizon from Macarthur. These are Ursa Minor (southernmost boundary 65°N) and Cepheus (55°N). Camelopardalis (53°N), Cassiopeia (52°N) and Draco (48°N) are three more constellations that are technically almost invisible from Macarthur and realistically they are. Approximately half of the constellation of Ursa Major is invisible in Macarthur, as are very small parts of Lynx, Cygnus, Lacerta, Perseus and Auriga. So, an MAS observer visiting the Northern hemisphere needs to concentrate on the constellations of Ursa Minor, Cepheus, Camelopardalis, Cassiopeia and Ursa Major, because the rest are visible from Macarthur. There are seven Messier objects in Ursa Major, two in Cassiopeia, one in Draco and none in Ursa Minor or Camelopardalis. Therefore, if you are seeking Messier objects, there are only three constellations to worry about and they will be visible for much of the year.
Below is a list of the fourteen northernmost Messier objects, (four of which are technically just visible from Macarthur and five of which are right on the horizon, so a trip North would enable them to be seen at the right time of year):
69°N | Ursa Major | M81 | NGC 3031 | Spiral Galaxy | Mag 6.9 |
69°N | Ursa Major | M82 | NGC 3034 | Cigar Galaxy | Mag 8.4 |
61°N | Cassiopeia | M52 | NGC 7654 | Open Cluster | Mag 7.3 |
60°N | Cassiopeia | M103 | NGC 581 | Open Cluster | Mag 7.4 |
58°N | Ursa Major | M40 | ~ | Double Star | Mag 8.4 |
55°N | Ursa Major | M108 | NGC 3556 | Spiral Galaxy | Mag10.1 |
55°N | Draco | M102 | NGC 5866 | Edge On Galaxy | Mag 10.0 |
55°N | Ursa Major | M97 | NGC 3587 | Owl Nebula | Mag 9.9 |
54°N | Ursa Major | M101 | NGC 5457 | Pin Wheel Galaxy | Mag 7.7 |
53°N | Ursa Major | M109 | NGC 3992 | Spiral Galaxy | Mag 9.8 |
51°N | Perseus | M76 | NGC 650 | Little Dumbell | Mag 10.1 |
48°N | Cygnus | M39 | NGC 7092 | Open Cluster | Mag 4.6 |
47°N | Canes Venatici | M51 | NGC 5194 | Whirlpool Galaxy | Mag 8.4 |
47°N | Canes Venatici | M106 | NGC 4258 | Spiral Galaxy | Mag 8.3 |
Not all of these objects will be visible through binoculars but concentrating on just Ursa Major, Cassiopeia and Draco greatly simplifies the objectives for anyone visiting the northern hemisphere from MAS and wanting to star-hop to Messier objects. However, this does not take into account the other governing factors, which are: weather; light pollution; localised light source glare; jet trails; and very late summer sunsets.
England is renowned for it's cloudy weather. When it is not cloudy the sky will often be hazy, permitting views of bright objects such as Jupiter and the International Space Station - but little else. Lichfield is under many air corridors, as demonstrated by this day-time image, in which about nine jet trails are visible, with others apparently dissipating:
Light pollution in the UK is much worse than in Macarthur. Naked eye astronomy is not what it was when I was a young man living in North London in the 1960's. At that time I learned the northern constellations very easily as I walked home from the tube station each night - but now it is difficult to pick out Polaris and the Little Dipper.
So how did I go? Well, with the use of binoculars instead of my 'goto' Meade 8" LX-90, backyard astronomy was a somewhat difficult experience but despite these difficulties at least I was able to observe M52 and M103 in Cassiopeia. Ursa Major was fairly easily picked out but my binoculars could not pick out any of the seven Messier objects it contains.
Maybe this article will be of some value to any others visiting the UK in the future from 'Dow Nunder'. Despite the difficulties, I still recommend taking your binoculars and giving it a go.
Article originally published in the October 2009 issue of Prime Focus, the journal of Macarthur Astronomical Society.