2009 says goodbye with a non-blue lunar eclipse

By Phil Plait | December 29, 2009 2:00 am

moon_eclipsedec2009Folks in Europe, Africa, and Asia can say goodbye to 2009 by viewing a very slight lunar eclipse on the last day of the year: Thursday, December 31. The event lasts for about an hour starting at 18:52 UTC, with deepest eclipse, such as it is, at 19:22.

Only a small part of the Moon will be in the deepest part of the Earth’s shadow, so this is nowhere near a total eclipse, when the Earth fully blocks sunlight from reaching the Moon. However, if you go out and take a look you’ll see the full Moon looking distinctly flattened on one side, and perhaps the rest of the Moon’s surface will look dusky. I’ve made a little image here to show you about how much the Moon will be covered, and approximately where. Like I said, only a small part will be darkened.

dec2009_eclipsemapNot everyone will see this; North and South America are basically shut out of this event since it happens on the other side of the planet and the whole thing’s over before the Moon rises. The image of the Earth here shows where the eclipse will be visible: if you can see where you live, then you can see the eclipse. The closer you are to the center of the map, the higher the Moon will be in the sky at midpoint of the eclipse.

The next lunar eclipse visible will be in June 2010, but it’s partial and will only be visible in Australia. After that, there is a full eclipse in December 2010 which will be seen by North and South America — though the farther west you are the better as far as decent viewing times go (it’ll be around midnight for me in the Mountain time zone).

Anyway, if you want to learn about lunar eclipses (like what I mean by partial versus total, and what an umbra and penumbra are) then take a look at the Mr. Eclipse site, which has great info.

I’ll note that this last eclipse of 2009 is also a so-called Blue Moon: the unofficial term for the second full Moon in a single month. There’s no real significance to it — the Moon ain’t blue, folks, despite a bunch of news sites already posting pictures of the Moon Photoshopped to look that color without explanation. But the real thing here is that celestial geometry is putting on a small show for you, and what better way to ring in a new year?

Tip o’ the umbra to AstroPixie for reminding me about this!

MORE ABOUT: Lunar eclipse

Comments (22)

  1. Quasar

    In the place where i am from.. People dont go out in the ecclipse time… Ironically my place is in the centre of the image….

  2. natasha

    hi will i be able to see it i live in uk

  3. Gamercow

    There’s no real signifigance to a blue moon, but I still enjoy them when they happen for some reason, because they are semi-rare, only happening twice a year. A lunar eclipse on a blue moon is even rarer, so yay! No woo-ism here, just a happiness for a rare-ish event. Kind of like thunder snow or lenticular clouds or moonbows.

  4. Plutonium being from Pluto

    There’s no real significance to it — the Moon ain’t blue, folks,

    How do you know our Moon isn’t feeling blue, BA? Have you asked her? 😉

    Maybe she’s disappointed by the whole LCROSS failing to provide a spectacular watery impact or the fact that her Indian & Chinese & US friends* have smacked down and gone and she misses them? Or perhaps the Moon just sighs and wishes she too could have a couple of friendly little rovers giving her some attention like Mars gets? 😉

    Perhaps the Moon likes the Blues and prefers it to jazz or bluegrass or even rock! 😉

    (There’s an interesting albeit off topic under-reported story for the year – the MER’s Spirit and Opportunity are *still* roving the russet sands of Mars after so many years despite only being designed to last 90 days or something like that!)

    @ Gamercrow : I’m with you there Blue Moon wise. I also think they are mildy cool. :-)

    But what’s thunder snow? Don’t think I’ve heard of that one …


    * I.e. Chang’e & Chandrayaan & the Lunar Reconnaissance Orbiter have all completed their missions and crashed , I think. Right?

    PS. MER’s for those who don’t know = Mars Exploration Rovers.

  5. Dumb Guy

    I miss the old website where you analyzed movies and discussed scientific misconceptions. Your topics were better then. That stuff could be used in a high school science classroom. The new stuff isn’t the same.

    Thanks for linking us back to the oldies but goodies.

  6. dcsohl

    Thunder snow – when you get lightning and thunder in a snow storm.

    @Gamercow – Blue moons are rarer than twice a year. They only happen about once every 2 ½ years. Phil outlines it here, but basically, in the course of 19 years there are 236 lunar cycles and 228 calendar months. Therefore you have 8 (or more – see Phil’s page) calendar months with double full moons. 228/8 = 28.5, so you get a blue moon every 28.5 months, on average. And, indeed, the next month with two full moons is August 2012, and after that not until July 2015.

  7. Yeebok

    Will the blue moon be a sign of impending doom, late December 2012 you reckon ? Place your odds here !

    Also, this link (to Southern Sky Watch) has a little on the subject if you need a link, Phil:

  8. Erasmussimo

    If the moon were just a few days old when the sun is directly over the center of the Pacific Ocean, would it then be a blue moon? 😉

    I wonder if we could measure the differences in earthshine attributable to differences in the reflecting surface of the earth?

  9. Stevo Raine


    By StevoR (a.k.a. Plutonium being from Pluto) 2009 Dec. 29th draft III~ish. 😉

    The Moon Goddess drifted lonely and restless across the magnificent desolation that was her home and very self. Selene, she’d called herself based on an old myth that she’d heard but an eye-blink of her perception ago. She was composed of demi-Higgs and super-charmed quarks and other particles and fields as yet unknown to Human minds and still outside their conception of the electromagnetic spectrum. An ethereal Spirit, she’d been here from the start, from the femtosecond the Moon had coalesced from the shattered remnants of Earth and Theia. Born in fire, collision and lava and shortly afterwards bombarded late into her birth night with a battering of asteroids and comets.

    After awakening and beginning her sleepless sentience, she then observed, reflected, wandered, felt and simply was for aeon upon aeon; night upon night. Sensing everything within her restricted domain of Moon and, if she stretched out her will, even the shared Earth-Moon space to which she was bound. For near eternity, almost all her life there had been nothing she could do but watch and wonder as comets came and went, as the reverberasting thump of the occasional new-forged crater made her not-quite heart not-exactly jump. She merely absorbed ever deeper in her being-home its cratered shades of grey, sinuous rilles and smoothly rounded peaks.

    After billennia of testing her limits of sensing – and they were vast indeed – she gradually became aware over so many aeons of something special rising and sparking on the world that lit up fully half of her and was her nearest and dearest of companions.

    Special creatures that Selene found she could inspire and connect with telepathically in the vaguest possible way. Come she called! It’s been so long! I seek your presence close with me! Inspire me and build me anew as I inspire you and cause your ambitions to reach for the very Moon I am!

    Selene learnt and followed their mayfly generations, watched progress rapid yet paradoxically so painfully slow. She yearned and burned for them and then, at last, they came .. but oh so briefly!

    She’d gained and lost such marvellous alien new friends in so agonisingly short yet long a time. She wandering amongst her internal landscape now, sliding herself against reminders of their presence. She caressed the descent stages of the six LEM’s the precious memories they contained, pressed herself to the lingering warmth in the minuscle craters where Chang’e and Chandrayaan met their ends.

    Selene loved the blues, she felt that mood crash down upon her now, far harsher than the feather-light touches of those wonderful men and their flying machines. It has already been so long, so long! she played a lonely not-note to herself on a non-existent harmonica equivalent its non-sonic waves unheard amid the airlessness.

    Selene called at wavelengths just barely outside the thick headed Humans range of mental hearing. O Come on! Please come already. Don’t give up on me, just get in spaceships and head to me now!

    The dogs heard inside and howled n the night and Selene strove and sought to somehow reach out.

    And on that distant world nearest her, Selene got the barest hint of contact – some silly woman pretending to speak for her and telling the opposite of her wants – and her wrath knew no bounds …

    The End?

  10. StevoR-Correcting

    Make that :


    “Selene called at wavelengths just barely outside the thick headed Humans range of mental hearing. O Come on! Please come already. Don’t give up on me, just get in your spaceships and head to me now!

    The dogs heard inside and howled in the night as Selene strove and sought to somehow reach out.”


    Instead. ;0)

    & we all know about the silly woman this refers to here don’t we?

    If not or if you’d like torefresh your memory of it click here :


    Never enough editing time & always too many typos. Sigh.
    ( Could have been too many beers & too late at night /early morn too. 😉 )

  11. StevoR-Correcting

    D’oh! Forgot all about poor old Kaguya; the recent Japanese version of the Chang’e / LRO / Chandrayaan style lunar mission too. Oops. Mea culpa. :-(

    If you’ve also forgotten then this may refresh memories :


    Or this :


    Or maybe best of all this :


    (How many links are we allowed to add to comments here again? Hope this isn’t too many. 😉 )

    Hope these are enjoyable & handy for folks – esp. those nostalgic for the old “furniture store” spaceprobe already! 😉

  12. John Baxter

    The Blue Men will be mooning.

  13. mike

    I am in atlanta georgia, of america… i saw a gagantic perfect circle around the moon that was huge in radious compared to the small moon perfectly in the middle. It was amazing and looked awesome. It lasted about 2 hours then faded out.

  14. Actually, a blue moon is *not* the second full moon in a month. This was an error introduced in an article in “Sky & Telescope” in 1946. See the Wikipedia entry on “Blue Moons” or the correction article in “Sky & Telescope” (linked via my name to prevent moderation) for a full explanation.

  15. Tom

    I prefer the Main almanac definition of a Blue Moon also. I don’t know if either definition is technically right, but I like the more complex definition of “the 3rd full moon in a season that contains 4 full moons.”

  16. Messier TidyUpper

    Actually, a blue moon is *not* the second full moon in a month.

    It is now. 😉

    It may have started as an error but it’s stuck and won’t be changing anytime soon or likely ever.

    @ 13. mike:

    Sounds like a spectacular lunar halo.

    Incidentally, the TV news here has just mentioned the Blue Moon stating its the first one ever for a New Years Eve – is this right?

  17. J-Bar

    At least I get something good out of a deployment to Iraq.

  18. Joakim Rosqvist

    Saw it here in Sweden, despite cloudy and snowy skies. Not quite like Phil’s picture. There was a long smooth gradient from fully visible to obscured.

  19. Elin

    The moon was, indeed, not blue, but it was fabulously bright and full last night. I was in Boulder for a New Year’s party.
    I am curious: why did it look so bright last night? Was a beautiful NYE treat.

    Happy New Year to you and my fellow BA’ers.


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