06 December 2011

Total Lunar Eclipse 2011 - in San Francisco

Saturday morning, we will witness a Total Lunar Eclipse visible from western North America and regions across the Pacific Ocean. In San Francisco, we will have a dramatic early morning spectacle of the fully eclipsed Moon setting on the Pacific just as dawn breaks. As with any total lunar eclipse, the Moon's surface will be completely covered by the dark 'umbral' shadow of the Earth, but it will remain visible, taking on an eerie appearance of rusty red, or deep grey, or a mix of colors. Every eclipse is a little bit different, so we wait in anticipation to see what happens Saturday morning.

The circumstances of this eclipse are outlined in detail in this informative Sky & Telescope article, and this excellent NASA Science News article.

The timeline for San Francisco (and the entire pacific time zone) are: start of eclipse at 4:45 am, start of totality at 6:05 am, and end of totality at 6:57 am. The glow of the dawn sky will emerge in the eastern sky shortly after 6:00 am, so the Moon will be in total eclipse as the sky begins to brighten, and by the time the Moon exits the total phase, the sky will be fully lit in advance of the sunrise at 7:13 am.

What does all this mean to the casual viewer? You will experience the best views and the most drama from 4:45 am until 6:30 am, when the Moon gradually changes from full to completely eclipsed, and the skies are dark enough to appreciate the beauty and subtlety of the lighting and color of the lunar surface. And as the Moon's brightness is attenuated as the Earth's shadow creeps across the surface, the backdrop of stars will begin to shine more brightly by contrast, revealing the wonderful winter sky at its best, with the constellations Taurus, Orion and Auriga around the Moon, and some of the most beautiful, bright stars in the entire night sky punctuating the skyscape.

I welcome the public to stop by Ocean Beach on the west coast of San Francisco for an early-morning star party, where I and others from the San Francisco Amateur Astronomers (SFAA) will have telescopes set up for public viewing. We will set up at the beachwalk just across from the Beach Chalet restaurant on Great Highway, starting around 4:30 am. But heed the advice of Deborah Byrd in this EarthSky article, and wear very warm clothes. You'll be glad you did, as the winter chill is quite intense just before sunrise.


Red Brick Film said...

Sounds like a wonderful time. I will be thinking of you folks when I am running the snowblower here on the east coast. Wanna borrow my parka? Probably doesn't get that cold in San Fran? I look forward to my next clear sky here....in April. Enjoy!

The Urban Astronomer said...

Thanks for the comment, Red Brick Film. We will think it is cold, but we are just a bunch of spoiled Californian's who think that 45 degrees is a deep-freeze morning at the beach :-)

-- Paul

Unknown said...

Do you think when it starts totality just after 6am the moon will be high enough to be seen above the Golden Gate Bridge from the Presidio (at sea level) or will the Marin Headlands block the view?

The Urban Astronomer said...

The Moon will be setting north of due west, so from the Presidio you might have a great shot of the Moon as totality starts, but it depends upon the angle you will have from your vista point. The headlands do post a possible issue. If you want to get a more precise measure, try an astronomy app such as Star Walk or SkySafari.

Good luck, and tell me how it turns out.

-- Paul

Sherry said...

Where would you suggest trying to see this in the north bay?

Sidewalk Universe said...

I sure wish I could join you on the coast! The view with the flat ocean horizon will be amazing! I will see Luna low against the Sierra's and I am counting the hours!

Have a great observe Paul!

The Urban Astronomer said...

hi Sherry - in the north bay, you need a good flat horizon to the west. If the hills and mountains on your western horizon are more that the height of your thumb (with your arm extended), then you will want higher ground to see the total phase. Best of luck!

hi Richard - thanks for the encouragement. Going to take any pictures?

-- Paul

New Yorker said...

Would twinpeak be a good location for this? Wish I could see it from Nob Hill but looks like I would have to bring my gear (80lbs) to another spot.

The Urban Astronomer said...

Twin Peaks will be good, as long as you can see the coast clearly.

Good luck!

-- Paul

Greg said...


(Looking WNW from the Mason St. area.)

Suggests a nice -5 Iridium flare occurring quite close to the setting moon. The azimuth is identical, 297, and the elevation is right about where the moon should be at 5:41. An Iridium transit across the eclipsed moon would be a real treat! :)

Someone get out there and see if it happens.

The Urban Astronomer said...

Greg: good find! Based on my location near Ocean Beach, it seems that the flare will be at 165 degrees, 19 degrees above the horizon, so not likely near the Moon from our vantage point, but a nice thing to look for nonetheless. Flares are location-specific, so there is probably some location in SF or Marin where it will appear to be right on the Moon. That would be a cool transit indeed.

-- Paul

NASA Night Sky Network said...

Thanks to you and all members of the San Francisco Amateur Astronomers for sharing your knowledge, telescopes & binoculars with the public! We heard you had a great turnout at Ocean Beach. Congrats!

The Urban Astronomer said...

We had a great turnout, indeed. The Ocean Beach parking lot was full, and the sky cooperated despite a thin layer of cloud. It was a brilliant way to start a day!

Thank you to all of the SFAA members for bringing telescopes and talking with visitors.

Greg said...

Oops, missed that fact that you'd be set up at Ocean Beach and not along Mason St. (where S. Pier GG would be in 'conjunction' with the moon.)

I misread the Heaven's Above data too. :(

Oh well, sounds like you folks did well. :)

Mitchell said...

I had a great time at Ocean Beach. I don't know much about astronomy and learned a lot from you. Thanks for sharing the telescopes and giving your talk. I showed up at Ocean Beach just wanting to see the eclipse not knowing about you and the amateur astronomers and you invited us over. It wouldn't have been as memorable without you and the group. The people I met were so nice. Thanks!