Skylights: Summer 2010

From our latitude in north London, the summer is not a good time for sky-watching. During the summer months, the Sun, at its greatest northern declination, is never far below the northern horizon at midnight, so the sky never really gets dark. We are experiencing 'astronomical twilight' and this continues until September. Coupled with our dreadful light pollution, it makes the summer months virtually useless at our Observatory. In addition, the ecliptic - the path of the Moon and planets, is very low in the night time sky, and consequently, any planets visible at this time will be low down in the south immersed in the horizon murk - more pollution generated by our fair City. During the summer time, people often travel abroad and they often go to places that are not afflicted with our levels of light pollution. Then for the first time they can actually experience the glories of a dark sky. They see the Milky Way arching high overhead with the great star clouds in Sagittarius low in the south, looking like diamond dust and the dark lanes of dust dividing the Milky Way into two streams. Low in the south lies the zodiacal constellation of Scorpio with its principal star Antares red in colour and easy to mistake as the planet Mars. Antares means 'rival of Mars.' Higher up, towards the south, the sky is dominated by the 3 first magnitude stars Vega,Deneb and Altair. These three stars are called 'the summer triangle'. Vega, a blue white star is almost overhead. It is the main star of the tiny constellation Lyra- the Lyre - an ancient musical instrument. There are some interesting objects in Lyra. Scan around Vega with binoculars and you will soon find the star epsilon Lyrae. This is a double star easily split with low magnification. Look at it with a telescope and each of the two components are split again - this is the famous double double. Almost midway between Beta and Gamma Lyrae is the M57 the Ring Nebula. Even a small telescope will show M57 as a small pale greenish disk, looking like a smoke ring. It belong to a class of objects called Planetary Nebulae so called because they exhibit small disks. They are the remnants of spheres of gas thrown off when the parent star long ago exploded as a Supernova. Deneb, the brightest star in Cygnus - the Swan lies in a rich part of the Milky Way, and scanning the area binoculars will reveal countless stars. Cygnus resembles a cross and the star furthest from Deneb is beta Cygni Albireo. this is one of the finest coloured double stars in the sky. A small telescope will split it easily into its two components. The brightest is a golden yellow and its companion a deep blue. Further south, Altair, alpha Aquilae - the Eagle, lies in a sparse area of the Milky Way. Just above Altair is a dark obscuring dust cloud. Sweeping south west through Aquila will bring us to the star cluster M11, a fine star cluster in a rich field of the Galaxy. Just after sunset, towards the west, Venus, Mars and Saturn are grouped together just below Leo. On July 10th, Venus is just above Regulusand in the same field of view in binoculars. After midnight low in the south east, Jupiter is rising in Pisces - the Fishes. This year, Jupiter looks decidedly odd as its South Equatorial Belt (SEB) is missing. But the Great Red Spot(GRS) is becomming more prominent. The annual 'fireworks display' - the Perseid Meteors is at maximum on August 12th at 21 hours, so it is very favourable and we should see a good display, provided that it isn't cloudy!

The sky map below shows the general appearance of the night sky and there are sections giving more detail about planets, the Moon, comets and others.

Overview

Of the planets, Mercury is very very low in the evening sky after superior conjunction - you would be lucky to find it! Venus is prominent in the western sky after sunset, gradually decreasing in altitude in July and will be close to Regulus on 10th. Mars now low in the west below Leo and will be lost to view by mid July Jupiter is now rising after midnight, low in the south east now in Pisces. Saturn joins Mars in the low south west and will be lost to view by mid July Uranus rises after midnight and will be within 3 degrees of Jupiter during July. Neptune is in opposition in August situated in Aquarius Perseid Meteors, max on August 12th predicted as favourable this year.

[The night sky from
Hampstead: Summer 2010 v]

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Moon

The Moon is one of the most impressive sights through a telescope. Even in a pair of binoculars much detail can be seen. The best times to view the Moon is about 3 days before and after first quarter, when the Moon is in the evening sky. Also there's the added bonus that the terminator (line between light and dark) is visible and we get some spectacular views of the lunar surface seen in high relief.


Phase	Full Moon	Last quarter	New Moon	First quarter
Date	26/07/10	04/07/10	11/07/10	18/07/10
Date	24/08/10	03/08/10	10/08/10	16/08/10
Date	23/09/10	01/09/10	08/09/10	15/09/10
Date	23/10/10	01/10/10	07/10/10	14/10/10

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Comets

Comets are also sometimes visible and can produce incredible public interest, like Comet Halley (1985-86) and Hale-Bopp (1997). In 2005 Comet Machholz was visible and Comet McNaught scudded through the northern sky in January 2007 and was easily accessable to the naked eye, albeit for just a few days. Normally none can be seen with the unaided eye at any given time but this can change. This was certainly the case with Comet Holmes which increased its brighness by a million times in October 2007 and remained visible to the naked eye for many weeks. During March 2009 Comet Lulin was moving westwards below Leo but it was a very faint object and not at all easy to locate.

During June, comet C/2009 R1 McNaught has been moving through Perseus and Auriga just about achieving 5th magnitude at the end of the month. It was very low in the north and difficult to locate. To stay abreast of any new comets, sign up for our news service.

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Other animals

Most of the phenomena above are reasonably periodic. But there are also sporadic events which we can see through the Cooke telescope like eclipses or even novae and supernovae (Please). And this summer (2010) we had another unexpected comet/asteroid collision with Jupiter seen from Australia. So keep your eyes on the skies or let us do it for you and you might get to look at some rare, beautiful and profound phenomena.

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Last modified by DGD: 01 July 2010 15:30