Friday, January 1, 2016

The January Sky

With new year and new month of January upon us, people in the Northern Hemisphere will still be treated to some of the longest nights of the year as, even after the solstice, the Sun won't be moving North very much anytime soon, meaning that changes in the length of t he night, while present, are very hard to notice So, with all of this night, what's there to see?

Cool Constellations
By nightfall in January the fall constellations are all very well-placed for early (emphasis, early!) evening viewing. First up, we will have one last chance to see the Summer Triangle, provided you have a good West horizon. Hurry, though, it will quickly disappear (at least in the West) for good by month's end. Moving onto more mainstream celestial landmarks for this time of year, the Great Square of Pegasus is rapidly sinking in the West and the Big Dipper is starting to climb in the Northeast. Starting at the Great Square, look at the double string of stars coming of third base as they constitute Andromeda. High in the North is ‘W’-shaped Cassiopeia, house-like Cepheus, and a twisted ‘V’ of stars, the mythological hero Perseus. Below Perseus is the bright Capella, alpha Auriga, and below his feet, the cloudy patch that is the Pleiades. In the early evening, the Southwest is a dark void populated by the dim constellations of Capricorn, Aquarius, Pisces, and Cetus, all 4 of which are to soon disappear. If you stay up a little later as in a couple of hours after nightfall (which is no chore this time of year), you'll see all the winter favorite like unmistakable Orion in the South, which also serves as a winter signpost to the stars. From Orion, follow a line from his belt down to blazing blue Sirius, alpha Canis Major. Following that line up will bring one to Aldebaran, alpha Taurus the bull. Imagining a line starting at bright blue Rigel (Orion's left foot) through red Betelgeuse (Orion's right shoulder) will bring you to Castor and Pollux, alpha and beta Gemini. Other winter favorites to look for include Canis Minor, Cancer, and even Leo if you wait into the night a little longer. Early birds? Well, getting up just before the Sun will bring a spring preview in the form of Virgo, Bootes, Corona, Hercules, Corvus, and even Vega just ahead of the rising Sun.

Planetary Perceptions
On the planet front, if you want to see any of our solar system neighbors, you had better be an early bird because 4 of the 5 naked eye planets make their appearances in the predawn morning sky at the start of the month and, by month's end, seeing any planets will require staying up until around midnight as Mercury will drop out of evening visibility by the end of the first week of the new month. Moving into the night, Jupiter and Mars both continue their climbs in the predawn Eastern sky while Venus continues dropping, which is what it began to do in October and then, noticeably in November. By month's end, Venus will be rising just ahead of the Sun in the predawn sky Also of note, the Moon will be making several near passes of these bodies in the early part of the month. As for Saturn, which disappeared into the dusk glow back in mid November, it will be visible low in the predawn Southeastern sky and actually relatively easy to spot by month's end. As for Mercury, it will disappear from the evening sky about a week into January but will reemerge as a morning object just ahead of the Sun by months end very near to blazing Venus.

Seeing Double
With the longest nights of the year upon us, this is the time when you can see the same star twice in one night, as is on the set in the evening and on the rise in the morning. Despite this being the first month of winter, the summer stars are still visible in the sky at dusk. The stars of the Summer Triangle make perfect targets because of their brightness. As for what to do, simply go out and observe the stars of the Triangle (Vega is best as it is the brightest and will be first to rise in the morning). That done, either go to bed or stay up and enjoy the night until just before sunrise. At that point, go out and look in the Northeast for your chosen star's return to the sky. How many people can say they saw the same star twice in one night that way?



Tonight's Sky for January 1: Ceres Discovered (1801)
It was on this date in 1801 that the largest asteroid, Ceres, became the first asteroid to be discovered.

At the time, there was a hypothesis known as the Titus-Bode Law (since discredited), which states that distances of planets from their parent star and relative to each other can be determined by mathematical formula. With the 5 classical planets, the pattern seemed to hold true save a gap between Mars and Jupiter. When Uranus was discovered, by pure chance, it fit the pattern, increasing belief in the Titus-Bode Law and causing a renewed interest in finding the missing planet that was hypothesized to be located between Mars and Jupiter.

It was on New Year's Day 1801 that Giuseppe Piazzi discovered this 'planet,' which he named Ceres after the Roman goddess of agriculture. The largest body in the asteroid belt, Ceres contains about a third of the Asteroid Belt's mass and its diameter is about a third that of the Moon.

Initially classified as a planet, Ceres retained that status for about 50 years. The turning point: the discovery of more small bodies in the same region, which eventually caused astronomers to realize that a whole new class of objects, asteroids (meaning 'star-like') existed in this region. In time, Ceres was reclassified as an asteroid and became officially known as 1 Ceres for the fact that it was the first asteroid ever discovered. Come 2006 and the whole Pluto reclassification/definition of 'planet' controversy, Ceres was reclassified also, getting promoted to dwarf planet. To date, Ceres is the only dwarf planet in the inner solar system. 

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