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.

Orionid Meteor Shower 2011

The Orionid Meteor Shower peaks for the next two mornings, October 21 and 22, as the Earth passes through a debris stream left by Halley's Comet. Like all annual meteor showers, the Orionids occur at the same time each year because the Earth, in its 365-day trip around the Sun, passes through areas of increased debris, leading to a much more focused period of time with meteors flying into Earth's atmosphere and creating those beautiful streaks of light that magically light the sky for a moment and then vanish without a trace.

The name Orionids tells us that the meteors in this shower appear to emanate from the constellation Orion, the beautiful winter sky constellation. But like the best meteors in any shower, you won't see Orion until after midnight as it rises out of the east. Meteor showers are best observed between midnight and sunrise, when you are viewing meteors entering our atmosphere on the 'front face' of the Earth. Given that sunrise is quite late this time of year, take advantage of that and get up just ahead of dawn's light, around 6:15 in the San Francisco Bay Area.

Image courtesy of Earth Sky.

The Last Vestiges of the Winter Sky

The young Moon graces the last vestiges of the winter sky this week, creating a beautiful pattern in the west for several evenings in a row. The big, bold constellations of winter including Orion, Taurus and Canis Major, and the very distinctive asterism the Winter Triangle are sinking lower each evening into the glow of the sunset sky, and on May 4th, 5th and 6th the Moon enters the picture to create a spectacular evening picture.

I have been doing Star Parties and outdoor presentations on astronomy the last few weeks, and the change from week to week has been dramatic. There is a natural change to the sky each evening, as the constellations and bright stars along the celestial equator and zodiac (ecliptic) move approximately 1 degree westward toward the sunset. At the same time, the length of each day is growing, meaning that these great winter constellations are disappearing rapidly into the glare of sunset. But there is nothing to worry about -- they will make their way around the sky to rejoin the view in the early morning, and continue the great ritual of the sky changing slowly from one season to the next.

Take part in "The Globe At Night" project - just look up at the sky tonight!

For the next week everyone is invited to participate in a global effort to measure light pollution and to learn about stars and the sky in your neighborhood, especially for those in big cities like San Francisco. The "Globe At Night" project invites people from around the world to take a few minutes in the next 7 days and look at one of the most beautiful constellations in the sky, Orion, and simply report how much of it you can see. It's easier than you think. And it's a great family project to show kids what you can see in the night sky.

The Globe At Night website provides all of the details, but in summary you compare what you see in your sky (your backyard, rooftop or any other convenient observing location) to a series of images on the Globe At Night website. By finding the image that best matches your view and reporting this on the website, you are helping to gather data from cities around the world on the relative light pollution in the sky. The constellation Orion contains stars of varying brightness, and depending upon the darkness of your skies, you will see more or less of these stars. The charts on the Globe At Night website show you Orion with differing "magnitudes" of stars, so for very light polluted cities you might only see the 1st and 2nd magnitude stars, whereas in darker skies you will see 3rd, 4th, or even 5th and 6th magnitude stars (the higher the number, the fainter the star).

Join the worldwide "Citizen Scientists" supporting this effort to increase awareness of the night sky, and take part. And bring along a friend. It's fun!

The Winter Sky Beckons

The Winter Sky beckons me to stop what I am doing and pay attention, for the view of the heavens in this magical season is unlike any other. Here in San Francisco, when it is not raining (as was the case for most of January through today), the air is dry and the atmosphere clear, giving the casual observer sparkling vistas into the heavens. And as this kind of weather happens with regularity in the winter, and the hours of darkness are at their maximum, it is all but impossible to miss the winter sky.

Evenings right now are dominated by the slowly fading planet Jupiter high in the west at sunset, and the colorful bright stars of Orion high in the southern sky, Canis Major and Sirius to the lower left of Orion, and Taurus and Aldeberan to the upper right of Orion. Facing north, the Big Dipper and Cassiopeia trade places every 24 hours, circling Polaris, the North Star. And later in the night to the east are a variety of treasures in Virgo with Saturn in the vicinity. Two weeks ago the morning sky featured the old Moon passing through Scorpios and Sagittarius, creating beautiful alignments that accented the eastern horizon at dawn.

The most important thing to do, if you want to see these amazing sky spectacles, is to keep your eyes open and look up - - nothing more than that is necessary to be captivated by the spell of the sky. No need for a telescope or binoculars. This time of year the stars dazzle in the night, and appear to be asking all of us to take a moment to contemplate their majesty and come to appreciate the universe, awaiting your view each night of the year.

KFOG Podcast - January 20, 2011

My monthly conversation with KFOG Morning Show's Irish Greg moved from the new Zodiac signs (such as Ophiuchus) to the Aurora Borealis to the big bold winter constellations such as Orion and bright stars such as Sirius. Click here to listen and get inspired to look up at the sky tonight!

KFOG Podcast - April 14, 2010

Winter Triangle

One of the highlights of the winter sky is the Winter Triangle. This shape is a nearly perfect equilateral triangle that shines in the southern sky over the next few months. It includes three of the most brilliant stars in the sky, and it is called an "asterism" because it is not a single constellation, but a combination of stars from three different constellations.

The first and brightest star is Sirius, the brightest star in the night sky. Sirius is close to the Solar Systems (8 light years) and has a slight blue coloration. Sirius is in the constellation Canis Major, the big dog that accompanies Orion. To the upper right is Betelgeuse, a red supergiant star in Orion that is a distinctive orange color. Betelgeuse is so big that if it was our Sun, it would envelop Mercury, Venus, Earth and Mars! And the third star of the triangle is Procyon, in the constellation Canis Minor, the small dog that accompanies Orion. Procyon is actually a double-star system with a faint partner star.

Inside the Winter Triangle you can find numerous clusters of stars. I spent some time looking here a few nights ago and was able to see quite a few of these clusters, even in San Francisco. My backyard has a dark western horizon so by looking through binoculars later in the evening I was able to see quite a bit in and around the asterism. Try this for yourself sometime soon.

Dominating the Autumn Sky: Pegasus

In November, the nights grow longer and the sky changes rapidly. The Summer Triangle gradually fades into the west, and Orion and the winter constellations have not risen in the east to dominate the night sky. Instead, we see the less prominent (but no less beautiful) zodiac constellations of Capricornus, Aquarius and Pisces in the south, and directly overhead the large constellation Pegasus with the very distinctive asterism "The Great Square" in clear view. The sketch of the constellation Pegasus shown here is courtesy of the Battle Point Astronomical Association.

Pegasus is named after the Greek mythological character of the winged horse. Some constellations look a lot like their mythological namesake, but in this case I am always challenged to see the winged horse in the sky. But no matter, the shape of Pegasus is distinctive, and the Great Square makes it easy to find. This time of year Pegasus is high in the eastern sky after sunset and it moves almost directly overhead by 10 pm. I was out in my backyard a few minutes ago looking at it and to best see it I had to sit back on a chair. The Great Square is so striking because, yes, it is indeed nearly a perfect square, but more interesting is that there are virtually no other bright stars inside the square to disturb the shape. All around Pegasus, however, are a good number of bright stars, some of which form the head and feet of the winged horse, while the stars on the north side of the Great Square are actually part of Andromeda. In fact, I use Pegasus to help me find the constellation Andromeda and that points us to the Andromeda Galaxy (but that is a topic for another post).

For an excellent set of illustrations and tour of the Autumn sky, visit this webpage from the Smoky Mountain Astronomical Society.