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From: TerryMoselaol.com Date: Sat, 31 Dec 2005 07:56:21 EST Subject: HNLS, IAA Party, 2xNM, Aurorae?, Quads, ISS Hi all, HAPPY NEW LEAP SECOND! The New Year will start at 00h 00m 01s on 1 January, on your watch, as an extra second will be inserted after 00.00.00 to compensate for the Earth's slowing rotation period! So what makes a body as massive as the Earth slow down? Basically, it's the tides. The gravitational pull of the Moon (ignore the Sun for this purpose) draws the Earth's oceans out in two opposite bulges - one towards the Moon where the pull is strongest, and one on the other side of the Earth, where the Moon's pull is weakest. The Earth rotates once per day 'under' those bulges, so they sweep round the Earth, causing almost two high tides each day, which pile up against the Earth's land masses as it rotates. The dissipation of this energy cause the Earth's rotation to slow down ever so slightly, hence the extra second that has to be inserted every so often to compensate. As a result of the law of the conservation of angular momentum, that means that the Moon also slowly recedes from the Earth, and so the length of the month is increasing by a tiny amount each year also! 2. IAA NEW YEAR PARTY - DIRECTIONS: Here are directions to the Tudor Cinema, Drumhirk Road, Comber, Co Down, for the IAA New Year Party on Saturday 7 January, at 7.30 p.m.: From the Comber by-pass, take the A22 to Killyleagh & Downpatrick. From the roundabout at the by-pass / A22 junction, Drumhirk road is just under 1 mile, on the right. Go up Drumhirk Road for 1/3 mile, and you'll see some cottages on the right, with a laneway opposite, surrounded by 'ranch-style' fencing. Go to the end of that laneway, where you'll find the car park beside the cinema. Be there promptly for first choice among the eats and drinks! 3. Two New Moons this month: I didn't mention this before, as it's really a 'non-event', but as the media & some American sources are hyping it up, I'm forced to comment. They're not rare! There are also 2 Full Moons in June 2007, and 2 New Moons in August 2008! In other words, they're far more frequent than Leap Years! And just as predictable. (And what about the two Last Quarters in May 2005? Or the two First Quarters in August 2006?) A synodic month (New Moon to New Moon) is 29.53059 days long, and every month except February is longer than that, so they're bound to recur on a regular basis! 4. AURORAE: There's a slight chance of auroral activity over the next night or two, but don't expect anything too spectacular. 5. METEORS: Look out over the next few nights for the first members of the first meteor shower of 2006, the Quadrantids, which peak on January 3d 17h, with a nominal zenithal hourly rate (ZHR) of about 100. Luckily, it's not affected by the Moon this year, so clear skies should reveal a good show of these moderately fast meteors. They are not usually exceptionally bright, so you'll need a good dark site to see them at their best. The radiant is in N Bootes, and is above the NW horizon as darkness falls. It then dips lower, below the Pole, at lower culmination, before starting to rise again in the NE later in the evening. With maximum forecast for 17h, you should look from the start of astronomical twilight on the 3rd, right through that evening for as late as you can manage, for the best views. Some will also be seen on the nights of 1/2 and 2/3 Jan, but the Quadrantids have a short sharp peak, so not many are seen on the nights before and after maximum. The radiant is at 15h 28m, + 50°, about halfway between the end of the 'Plough' handle and the head of Draco. In a very dark sky you might see about 40-50 per hour early on the evening of the 3rd. 6. ISS: Another series of evening passes of the ISS starts on 1 January, although the best ones don't start until a few days later. Details on www.heavens-above.com. Clear skies to all - especially on 29 March! Happy New Year to all, Terry Moseley
Last Revised: 2006 January 3rd
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