the moon 31-12-09

[astropete]

just a reminder, there will be a partial eclipse of the moon this new years eve. the eclipse starts at 1852hrs and ends at 2130hrs, the moons southern tip will be in shadow and all in all 8% of the moon will be eclipsed. good snapping.

[DarkerSky]

Thanks for the reminder.

It is also a Blue Moon - the 2nd full moon this December. A rare event indeed!

[astropete]

i always wanted to know what was meant by a blue moon, thanks for telling.

[DarkerSky]

Astronomically, a Blue Moon is a 2nd full moon in any given calendar month. That is its most popular definition - but a definition that only goes back as far as an an article in Sky & Telescope in 1946.

Meteorolgically, a Blue Moon can mean the colouration of the moon as blue due to some combination of atmospheric effects - not sure what tho.!

[TheThing]

Meteorolgically, a Blue Moon can mean the colouration of the moon as blue due to some combination of atmospheric effects - not sure what tho.!

Mostly dust in the atmosphere caused by volcanic eruptions. After Krakatoa in the 1800's, the UK witnessed some marvelous blue moons.

[ringz]

Sky and Telescope retracted that definition of a blue moon several years ago. The true definition is way more complicated

Unfortunately their wrong definition has propagated everywhere.

http://www.skyandtelescope.com/observing/objects/moon/3304131.html

--

Martyn.

[Talitha]

I hope a lot of you get to see it, the event will be over before moonrise here.

There will be a 'penumbral' eclipse going on, too. See the inner circle on the attached graphic? That's the dark part of the Earth's shadow (umbra) which takes a 'bite' out of the Moon.

The outer circle is the Earth's 'penumbra' (from the Latin paene umbra which means 'almost shadow'). When the moon passes through our penumbra it will darken a bit but not much... might be a fun project to catch a few 'before' and 'after' shots.

If anyone would like to give it a try, here's the time schedule for London:

5:05pm Moon not yet in penumbra

6:05pm Moon half way covered by penumbra

6:55pm-7:55pm Moon totally inside of penumbra

8:35pm Moon half way out of penumbra

9:35pm Moon clear of penumbra

So if you get a few shots of the Moon before it enters and then a few while it's totally immersed, you'll get a nice comparison of the brightness.

[brianb]

here's the time schedule for London

Actually, for lunar eclipses, the times are the same everywhere that the Moon is visible. Just remember that the times given are GMT / UT.

For anyone in say India it might be interesting to plot the Moon's brightness at 5 or 10 min intervals ... with the Moon being low here in Western Europe, changes in atmospheric absorbtion as the Moon gains altitude will probably swamp the effects of the eclipse.

[daz]

My forecast shows wall to wall as per flippin' usual!!