Saturday, December 18, 2010

Mongolia | Zaisan | Full Moon | Lunar Eclipse

Unless you have spent the last couple of months indulging in some totally heedless Bacchanalia in a basement bar in Greenwich Village you no doubt know that there is a Total Lunar Eclipse scheduled for December 21, 2010. In the Western Hemisphere the eclipse will fall on the same day as the Winter Solstice; here in Mongolia it will occur the day before. 
Phases of the Eclipse, with Total in the Middle. For a more detailed view see Lunar Eclipse Phases
Some of the best views of the Lunar Eclipse will be from the east coast of the United States. In Mongolia the situation is complicated to say the least. Here is the schedule (all local Ulaanbaatar times): 

Penumbral begins:  1:29 pm
Partial eclipse begins:  2:33 pm
Total eclipse begins:  3:41 pm
Full Moon at 4:13
Greatest eclipse:  4:17 pm
Total Eclipse ends: 4:53 pm

Moon Rises at 4:57
Sun Sets at 5:01

Partial eclipse ends: 6:01 pm
Penumbral ends: 7:05  pm

As can be seen from this the eclipse begins and the period of total eclipse ends before the moon rises and the sun sets. Thus it will rise during the partial eclipse phase when the sun is still up.  Exactly how the moon will appear when it first rises and then after the sun sets, when it is still in the partial eclipse phase, is unclear. I will be at the summit of Zaisan Tolgoi from 4:00 pm onward on the 21st to find out, however. 

Now there is an additional complication: the forecast for the 21st is snow, with a high temperature of 3º F and a low of minus 27º F. If the skies are clouded over it might not be possible to see the moon at all, regardless of the eclipse phase. 

Eclipses, both solar and lunar, are big events in Mongolia. See the Solar Eclipse of 1997.


  1. So you live in UB? You say that the lunar eclipse will start @ 16:00 on Dec 21. Is that correct? "coz my understanding was that it'll happen at 4:00 am of Dec 21.

  2. 4:00 AM Eastern Standard Time. That’s 5 PM Mongolian Time. The total eclipse begins at 07:40:47 Universal Time (GTM) and the point of the greatest eclipse occurs at 08:16:57 UT. Convert Universal Time To Your Time Zone.

  3. Thanks a lot! I hope today's weather will allow to watch lunar eclipse.

    P.S. Do you have detailed bio? What do you do in Mongolia?

  4. Still calling for snow at the moment. See My Biography. I try to do as little as possible, although I am not always successful.

  5. Mongolia is full of of air pollution maybe it'll look bad

  6. Ulaanbaaatar has a lot of air pollution, not Mongolia in general. 99% of the country is air pollution free. The Gobi Desert has the clearest night skies I have seen anywhere in the world.