Ringing in the New Year

Saturn dominates the night sky throughout as the New Year begins. Rising a bit after sunset, the ringed planet is visible all night.

Saturn will vary its ring tilt quite a bit this year, starting at about 12.6 degrees this month, increasing to a maximum of 15.4 in April then shrinking to 6.6 in December. It reaches opposition on Feb. 10 and continues to be visible until early August.

Evening twilight as the year opens is dominated by brilliant Venus, joined later in the month by Mercury. Most of the other planets are too close to the sun to observe right now, peeking cautiously into the morning sky and awaiting their chances later in the year.

Here’s a preview of some other shallow sky events of 2007:

There are two lunar eclipses in 2007. The first one, on March 3, is only barely visible here: the moon will already be out of the umbra (the central part of the Earth’s shadow) by the time it rises, and the darkening of the moon in the penumbra is so subtle that it’s not likely we’ll be able to see anything when the moon is still down on the horizon.

But the second eclipse, on August 28, will give us a much better view. This will be the first since 2000 in which the moon passes through the center of the earth’s shadow, making (in theory, anyway) a darker than usual eclipsed moon, and an unusually long eclipse (totality lasts an hour and a half). Here on the west coast we’ll be able to see the whole event — in states farther east, the moon will set before the eclipse is over.

The moon makes lots of close passes with planets (Saturn, Uranus and Mercury) and with bright stars, but mostly we don’t get to see any actual occultations from here. Boo!

2007 gives us another Mars opposition, on the day before Christmas — but Mars will still be relatively far away and small. Between the small size and our typical December weather, this probably won’t be as impressive an opposition as the last few have been. It only gets to 15.9”, compared with 20.2 in 2005 and 25.1 in 2003.

But don’t give up hope — there’s good news too. Mars will be much farther north this time, which means that at opposition it will soar to 80 degrees above the horizon. Even a small planet, when it gets that high in the sky, can show quite a bit of detail, so if we get lucky on the weather 2007 might be a pretty good Mars opposition after all.

Meanwhile, it’s not looking good for Mars Global Surveyor. The spacecraft, which has sent back so many useful images of the red planet, was last heard from on November 5, reporting problems with one of its solar panels. Searches using both ground based telescopes and other Mars spacecraft have proved futile, and MGS is feared lost. It’s still possible that the surveyor could make a miraculous recovery, but as more time passes it’s looking less and less likely.

Jupiter starts the year in the morning sky, moving toward its opposition in early June; it will be visible in the until December. Farther out in the solar system, Neptune will reach opposition in mid August, Uranus in early September, and Pluto in mid—June.

What about comets?

We start the year with two comets visible, but neither one is very bright. 2006 HR30 (P/Siding Spring) reaches perihelion in early January and might reach 10th magnitude. 29P/Schwassmann—Wachmann will be visible in Taurus during the first few months of the year. This comet has unpredictable outbursts, so it’s hard to say how bright it will be — perhaps no brighter than 12th magnitude. In August, it will reappear in the morning sky in Auriga.

A few other periodic comets we can look forward to this year include 2P/Encke, expected to reach binocular brightness in late March and early April; 96P/Machholz, visible in the morning sky in late April but probably never getting brighter than 9th magnitude (discovered by our own comet hunter extraordinaire, Don Machholz); and 8P/Tuttle, which should become visible in binoculars or perhaps even to the naked eye at the very end of the year. It may get even brighter in 2008.

Some interesting solar system space missions launching in 2007 include Dawn, launching in mid—June, which will study the asteroids Ceres and Vesta up close, and the Mars lander Phoenix, in early August, which will study soils of the Martian arctic looking for clues to the planet’s water history. The new Herschel infrared space telescope is also scheduled to launch some time in 2007. And the New Horizons mission, which launched last year, will have a close encounter with Jupiter in February, where it will pick up some gravity assist to slingshot it out toward its planned Pluto encounter eight years later.

So there’s lots to see in the upcoming year – but start off by ringing in the new year with a good look at the ringed planet.