27 January 2013

Seeing the International Space Station

International Space Station
The International Space Station, or ISS, is a wonderful sight to see. It is Earth's 2nd largest satellite (after the Moon, of course). The ISS shines brightly because of the reflective surfaces across its trusses that shine brightly in the sunlight, and make the ISS look like a bright planet that moves relatively quickly across the sky.

The ISS only appears in the sky for a short while after sunset, or before sunrise. It is in orbit about 225 miles above the surface of the Earth; for example, shortly after a sunset the ISS catches sunlight and shines as it travels across the sky. When you get a very good alignment and it passes nearly overhead, it can reach the same magnitude as a bright Venus, and therefore be easy to spot. On such a pass, it takes about 5 minutes to travel from horizon to horizon, covering over 1000 miles in that time.

ISS visibility depends upon your location on Earth, since the best times to see the ISS in one part of the globe won't be the same as another. NASA has an an excellent web resource for this; for ISS sightings in San Francisco, we have morning passes right now, and will soon have good visibility in the evenings starting on February 5th. The iPhone app ISS Visibility is quite helpful for locating the ISS, with maps and easy-to-follow directions.

Best of luck seeing this wonderful sight. Image courtesy of NASA.

17 January 2013

Astronomy Events in 2013

Every year is full of special moments in the sky as planets and stars and the Moon align to create noteworthy patterns and special views. 2013 will be marked by many special moments, so here's a quick overview of them.


Comet Hale-Bopp
The event of the year could be the fly-by of Comet Ison, currently en route for a November 28th close encounter with the Sun, potentially lighting up the night (and even daytime) sky. More information on Comet Ison here.


Mark your calendar for February 15-16, when Asteroid DA14 will pass within 10,000-20,000 miles of the surface of the Earth. This is a big asteroid, at 125 feet, and could cause considerable damage if it was to impact. Lucky for us, we will not have anything to worry about. More here from Earth Sky.


Only one eclipse will be of significance for the West Coast, on October 18th when the Moon will pass within the Earth's penumbral shadow. This partial eclipse will start before moonrise in California, but once the Moon rises, should be a nice sight.


Every month as the Moon slips past planets and stars in the night sky, there are moments when a distant object is blocked out by the Moon, called an Occultation. This year there are several close encounters that should be quite fun to watch from the Bay Area. Depending where you are on Earth, you can see more or less of these events. A few noteworthy ones: January 21 and March 17 when the Moon passes very close to Jupiter; and February 28-March 1 and July 15-16 when the Moon passes very close to the bright star Spica.

Be sure to check out the Year In Space calendar for 2013 which has fascinating facts and is a wealth of astronomy information for every day and month of the year. And happy viewing this year!

Image courtesy Wikimedia Commons.

07 January 2013

Alignments in the City Sky

Jupiter, Orion, and Sirius
I am viewing the sky this evening from one of the most densely populated urban areas, Manhattan. Looking up at the night sky here, you can't see many faint stars, but you can still see plenty of the brighter ones. Tonight looking toward the south, I was easily able to spot the fantastic alignment of Orion's belt, pointing downward toward the brightest star in the sky, Sirius, and pointing upward to the brightest planet in the sky in the evening, Jupiter. As Jupiter gradually moves in its orbit around the Sun, it will soon move out of alignment with Sirius, Orion's belt, and the bright star Aldeberan in the constellation Taurus. By the middle of 2013, Jupiter will be well on its way to the next sign in the Zodiac, Gemini. But for the coming weeks, you can enjoy the bright celestial alignment that can been seen from just about any location on Earth, even in the middle of an urban jungle such as NYC.

Image courtesy of Sky Safari.

02 January 2013

Quadrantid Meteor Shower 2013

The Quadrantids peak this evening and continue through Thursday January 4th, lighting up the sky with 'shooting stars' that are enchanting to see, if you have dark clear skies and are able to brave the wintery cold night. The Quadrantids ring in each new year with a good display of meteors, and are favorable for us in the Northern Hemisphere because the 'radiant' (the point from which the meteors appear to emanate) is high in the northern sky. Here are some helpful articles with more details about the shower.

EarthSky.com has a thorough article.

Space.com has helpful sky maps.

To enjoy the Quadrantids, follow the usual rules for a meteor shower: (a) dress warmly and have blankets or a sleeping bag, (b) avoid direct lights such as house lights, yard lights and street lights, (c) give yourself time to adapt to the darkness so your eyes can pick up faint meteors as well as big bright ones, and (d) give yourself a view directly overhead with as few obstructions as possible. If you get lucky, you can see up to 40 meteors per hour.