30-08-2008 September Night Sky (Article 152)

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Simon Kenny
Posts: 527
Joined: Tue Feb 12, 2008 9:17 pm
Location: Shannon, Co. Clare, Ireland

30-08-2008 September Night Sky (Article 152)

Post by Simon Kenny » Tue Dec 30, 2008 9:20 pm

September Night Sky (Article 152)

Many astronomers across the country have had little or no opportunity to view the sky recently given the almost monsoon like weather conditions. It seems that June and July are months to wrap up the telescope and put it in the attic, but now with all the schools reopening we are hopefully due some clear skies in the coming weeks.
If you have a very low western horizon, you might be able to spy Venus setting between 8.30pm and 9pm. If you scan around Venus with a pair of binoculars you might be able to see two other bright stars to the left, which are the planets Mars and Saturn. Be certain that the Sun is below the horizon before scanning with binoculars; otherwise you risk instant permanent blindness if you spy the Sun by accident.
If you turn your head to the left, you will notice a bright star low in the southern sky. This is in fact the planet Jupiter. This month is the time to get a good view of it and it’ll be visible in that position for the rest of the month. If you have a telescope, then you will be able to see its disk fairly easily with its cloud bands visible. You might also be able to see its 4 Galilean moons nearby as star points.
For an hour either side of midnight, you will be able to see the planets Uranus and Neptune using a telescope if you know where to look. The maps are a bit too detailed to be shown here so we’ll be showing them in the September club meeting on Wednesday the 3rd in Mary Immaculate College in Limerick at 8pm.
For the first week, the moon is visible skimming the south western horizon in the evening twilight, working its way from a crescent towards first quarter (half moon) and getting higher as it does so. By the 15th, the moon is now full and is highest in the sky at approx 1am. In the early hours of Saturday the 20th, the moon will pass through the Pleiades star cluster. It enters the cluster at about 2.30am and leaves it at about 4.30am and will be visible next to it until sunrise. The apparition will be visible to the unaided eye, although through binoculars it makes for a spectacular sight and even more so in low power telescopes. At this stage the moon has what is known as a waning gibbous phase, meaning that the moon is two thirds full and has already gone past full moon.
By the 22nd, the moon had reached last quarter (half moon) phase, and is visible in the early hours of the morning. For the following 8 days you will see the moon plunging towards the eastern horizon as it makes its way towards a crescent phase.
On the weekend of the 26th-28th, the club will be holding its annual Whirlpool Starparty in Dooleys hotel in Birr county Offaly. Speakers include Ian Ridpath, Judith Phiper, Damien Peach, Sally Russel, Deirdre Kelleghan, Arron Golden, Lorraine Hanlon and Niall Smith, see our website for more details.

Next meeting is on 3 September at 8pm in Mary Immaculate College in Limerick.

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