Sunday, December 19, 2010

SECOND ROCK FROM THE SUN

By Ken Harrison

Just in case we have any lunatic anoraks about, that very bright star that can be seen, fairly low down towards the east before dawn is the planet Venus*. It's obvious and much brighter than any star. Easily seen with naked eye, but a telescope would improve clarity.
For the really keen, just before sunrise (about 8.15am) on Tuesday, 21st December there will be a total eclipse of the Moon. It's not expected to be spectacular as the eclipse will occur just before the Moon sets below the horizon.
If the weather is clear, find an viewing point unobstructed by buildings and such like, as possible.
Advanced info: there will be a partial Solar (Sun) eclipse on January 4th. Then a few nights later, yet another meteorite shower storm (shooting stars).

*Venus is the 2nd planet from the Sun. It is covered in a highly reflective cloud layer .......of sulfuric acid (H2SO4). It lower amosphere is essentially carbon dioxide, while atmospheric pressure is about 90 times that of the Earth.
The planet is named after the Roman

3 comments:

Ken Harrison said...

Remember, the eclipse occurs BEFORE the Moon sets at about 8ish am.
Best to start looking around 7am-ish...leave it too late, you may not be able see the Moon as it could be already eclipsed.
One possible advantage point is Gallows Wood area...another advantage is that one can get a bacon sarnie and a mug of tea from the butty bar in the lay-by. I think it opens at 7am.
Some folks may see the eclipse on the way to work.

If keen, assess the situation:
?clear sky, ?weather ok - don't risk going out if the roads are dICEy.

The predicted viz for Tuesaday is CLEAR - even the Sun should come out during the day!!

Ken Harrison said...

A few more notes.....for the really keen, they could start gazing from just after 5am....but that's a bit too early for us sensible folk.

In this lunar eclipse, the Earth gets between the Sun and the Moon...now when this happens the Earth cast two types of shadow - the umbral and penumbral.

Some of the Sun's rays are deflected off the Earth's curved surface, and this casts an outer, partial showdow.

Solar rays passing thro' the Earth's atmosphere will be filtered and infra-red rays will be cast off the Earth's dark side creating a smaller inner core of an orange-glowing shadow - or umbral shadow.

In ideal circumstrances, as the Moon passes thro the penumbral and umbral shadows, the Moon will first darken - then gradually reappear in the umbral (orange) shadow and then darken again as it passes thro the opposite side of the penumbral shadow. It takes time.

I'm not certain exactly how much of this sequence anyone watching from around Brigg will see as the Moon is due to set either just after, or possibly at the latter stages of the sequence. And it will be low on the horizon....but, nevertheless, given the chance, a spectacle worth watching.

ps Is 21st December the official date for the start of Winter - the Winter Soltice - time when the Earth/Sun angle is at it's most southern extremity......After the soltice, the Sun is on its way to us!!

Ken Harrison said...

Midnight: Temp -10'C
Viz - Clear - Moon overhead and very clear.

For info: There is no 'air temperature' on the Moon as it has no atmosphere.
But its surface temp (facing Sun) is in the range of 100'C to 160'C.