KFOG Broadcast - Dec 13, 2012

Today I was a guest on KFOG In The Morning, with DJs Tim Jeffreys and Greg Gory. We had a spirited discussion about the Moon and Sun and how they conspire to create King Tides, and discussed the Geminid meteor shower. Click here to listen to the broadcast.

Geminid Meteor Shower 2012

One of the best meteor showers of the year, the Geminids, peaks the night of Thursday December 13th and continues through the early morning hours of Friday December 14th, as seen from the western hemisphere. This annual shower is generally a good show, and this year will be fully uninterrupted by moonlight, as the Moon is new and will leave the skies dark.

Geminid Meteors

Annual meteor showers are created as Earth passes in the wake of another celestial body, normally an asteroid or comet with a fine trail of dust and debris that burn up in Earth's atmosphere. In the case of the Geminids, they are caused by the remnants of an asteriod. This year, a new comet has left an additional amount of dust and debris and might cause the meteor viewing to be extra-intense.

To see the Geminids, find a dark location away from bright lights or direct lights, dress very warmly, and give yourself 5-10 minutes to adapt to the darkness. Look up and you'll see the meteors, as they will streak across any part of the sky. The common aspect of these meteors is if you trace the path of the meteor backwards, they will appear to emerge from the constellation Gemini (see image). But don't worry, you don't need to point any one direction or use a telescope. Meteor showers should be relaxing events, with plenty of time to gaze into the heavens and enjoy the glorious night sky.

Image courtesy of Sky & Telescope.

Asteroid Sighting

Ceres and Vesta

Finding the major planets in the night sky is easy, since the biggest and nearest planets outshine most stars. But the more distant planets and the asteroids pose a challenge, as you need to use a star chart or other guide to locate these wanderers, and you'll need binoculars or a telescope to see them.

Right now, two of the biggest asteroids are fairly easy to spot, being located high in the night sky and nearby a variety of easy-to-locate landmarks. There are good articles with additional details on the web, including Sky & Telescope and MSNBC Space. The MSNBC article has some very simple diagrams showing the exact location of the asteroids Ceres and Vesta, as they wander through the constellation Taurus. Using binoculars, they should stand out as fairly bright points of light and be distinct against the backdrop of stars in Taurus. I am not an 'asteroid hunter' and don't have lots of experience finding these, but I have used binoculars and telescopes to find the faint outer planets Uranus and Neptune, and anticipate that Ceres and Vesta will be similar. I'll report findings here on the blog comments.

The NASA spacecraft Dawn is on a mission to visit both asteroids, having already orbited Vesta and now is en route to Ceres. (Note: although Ceres was historically classified as an asteroid, it has recently been reclassified to a Dwarf Planet, just like Pluto!)

Image courtesy of Sky & Telescope.

Jupiter at Opposition: Closest approach of the Year

Jupiter at Opposition

Every 13 months the planet Jupiter and Earth align with the Sun, a special moment called Opposition. That represents the closest approach between the two planets, and means that Jupiter is at its brightest and 'fullest' for the year. It's unmistakeable when it rises, the brightest light in the east after sunset, blazing in its glory in one of the most spectacular parts of the night sky, near the constellations Orion, Taurus and Auriga and a large number of bright, colorful stars.

It's easy to spot the four brightest Moons (also known as the Galilean Moons) of Jupiter if you use a simple telescope or binoculars. With Jupiter at opposition, now is the time to take a closer look. If you want to actually identify which Jovian moon is which, use this handy app from Sky & Telescope.

Image courtesy Space.com.

Full Moon, Partial Eclipse, and Jupiter

Full Moon

This week we are presented with a collection of celestial alignments that are quite visible in an urban setting. The Moon reaches full phase on Tuesday, and will pass through the busy area of the night sky near the constellation Orion, the beautiful star cluster known as the Pleiades, and the bright planet Jupiter (on Wednesday). As it does, take a closer look with a pair of binoculars or simple telescope, since these objects will be easy to locate and are engaging to view up close.

The morning of Wednesday November 28th, the Moon touches the edge of Earth's shadow in space, creating a faint darkening of the northern limb of the Moon, also known as a Partial Eclipse. For San Francisco and the western US, the Moon's darkening will be most visible just before sunrise, during the 6:00 am hour.

Image courtesy of Sky & Telescope.

Leonid Meteor Shower 2012

Leonids

The Leonid Meteor Shower peaks this weekend, November 16-17, giving viewers a chance to enjoy the dazzling sight of bits of light streaking across the night sky. The Leonids occur each November as the Earth passes through the remnants of Comet Tempel-Tuttle, a minor comet that has left a stream of particles in its wake. As Earth glides through the meteor stream each November, we experience the beauty of the cosmic collisions that intensify and glow in our night sky.

To see the Leonids, find a dark location and let your eyes adapt for at least 10-15 minutes. Dress warmly and relax on a blanket or lawn chair, looking overhead or somewhat toward the east. The 'raidant' of the meteor shower is in the constellation Leo which rises high in the east after midnight, and the meteors will appear to emanate from that spot, but will shoot all over the entire sky, so most important is to have a view of as much of the sky as possible. City dwellers should find the darkest possible spot. In my own backyard, I place myself in a dark area where the local streetlights are shielded from view, allowing my eyes to adapt and see fainter meteors.

Stay warm, and enjoy the show. Here are some additional resources:

Space.com article about the Leonids.
Earthsky.org article about the Leonids.

Image courtesy howstuffworks.com.

Jupiter Returns to the Evening Sky

Jupiter rises into view.

The Moon heralds the return of mighty Jupiter to our evening skies. As October nears its end, the giant planet Jupiter is arriving in the evening sky earlier and earlier each evening, now shining brightly soon after 9:00 pm. Jupiter is dazzling in its new perch for the coming months high above the constellation Orion near the bright star Aldeberan. Jupiter will be approaching its brightest of the year in the coming weeks, as we move into an alignment of Jupiter at opposition in early December. Watch the nearly Full Moon glide past Jupiter early next week. And with the late sunrises that we experience this time of year, Jupiter is visible nearly overhead in the early morning hours before sunrise.

Image courtesy of Sky & Telescope.

Red Stars at Night

Evening Sky this week

This week, the dusk sky features alignments of planets, stars and the Moon that will accentuate the western horizon with two red ‘stars’ glowing in the colorful haze of twilight. The two ‘stars’ are a planet and a star, but both are quite distinctive because of their orange-red tinge. Mars is passing near the red supergiant star Antares, and the Moon will be sweeping past the two on the evenings of the 17th and 18th.

If you have an extra-clear western horizon, you can try to locate the faint Mercury and the very young Moon shortly after sunset on Tuesday 16th. This will require the use of binoculars to spot them, but if conditions permit, it will be quite impressive to see.

Image courtesy of Sky & Telescope Magazine.