Mohawk Valley Astronomical Society

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Planet Watch 2013

by Perry Pezzolanella

This will be a wonderful year to explore the night sky with the evening sky dominated all year by either of the two largest planets, Jupiter and Saturn. There will be several additional celestial events to assure a smorgasbord of objects to look at that will include asteroids, comets, meteor showers, satellites, Iridium flares, and the International Space Station. There could be a surprise aurora or two, beautiful Moon and planetary conjunctions, and possibly even comets. 2013 could be the year for two bright comets starting with Comet PANSTARRS in the March evening skies being possibly as bright as the brightest stars. There is great expectation of the brightest comet in our lifetime arriving by November called ISON, named after the International Scientific Optical Network where it was discovered. It will be well placed in our Northern hemisphere after so many bright ones have appeared “Down Under” and out of view from us, and it could last into January. Could it be brighter than Comet Hale-Bopp and rival Comet Lovejoy and Comet McNaught, or could it flop like Comet Kohoutek? This comet could be the most newsworthy event of the year, and possibly of the decade.

There will be a subtle lunar and solar eclipse this year. A penumbral eclipse of the Moon will be visible on October 18 as soon as it rises but the shadow will be subtle as the Moon never touches the dark umbra. Because it does penetrate deep into the penumbra, it will be worth noting if the southern portion of the Moon has any noticeable dimming. The next total lunar eclipse is April 15, 2014. There will be a partial solar eclipse on November 3 right at sunrise and it may be possible to see the Sun up to 35% eclipsed. It will appear like a thick crescent and the eclipse will quickly end as the Sun climbs higher. Unfortunately this is one of the cloudiest times of the year, which will add to the challenge, but there is another chance shortly before sunset on October 23, 2014. That will be the last eclipse of the Sun here until August 21, 2017 and that one will be impressive with the Sun high up and 70% eclipsed. The horns of the crescent will be pointing downwards to add to an unusual and almost eerie appearance as totality races south of here.

Jupiter clearly dominates the evening sky all winter with no competition from any other planet and continues to do so into early spring when Saturn begins to rise early enough to take over by late March. Jupiter soon fades into the twilight and Saturn dominates nearly the rest of the year. It will be the planet of the year for all of the star parties during the warm months. It will not fade away into the bright evening twilight until October when Jupiter will be back shortly after midnight to begin dominating again. Neither planet will have competition from Mars as it remains dim and small until early next year. By then it will give Jupiter and Saturn some fierce competition. Mercury will be a curiosity in June as it is at its best at that time and hopefully the better weather will allow for more viewing than usual and possibly a chance to photograph some elusive surface detail. Venus will also appear low in the west during June and struggle to gain elevation for the rest of the year. It will finally gain some height by December but will not last long since this is one of the poorest apparitions possible. Uranus and Neptune are never brilliant, but both are fun to locate and observe; both will be visible in the evening from August until next February. Here is the breakdown for each planet in the evening sky during 2013:

Mercury: This elusive, iron world is always challenging to find, but has become better understood thanks to the MESSENGER spacecraft that has been orbiting it since March 17, 2011. It is easiest to see in the evening from May 30 to June 22, being highest above the horizon on June 12. Mercury grows steadily through this period from 6 to 10 arcseconds across as it approaches Earth and its magnitude will hover around 0. It will go through phases like a tiny, coppery version of the Moon, from nearly full to a thin crescent.

Venus: This deadly, inferno world has a poor evening apparition later this year as it barely rises above the tree tops and telephone poles until early December and even then its highest appearance will be brief as it reaches inferior conjunction between the Sun and Earth on January 11, 2014. It will be at its greatest eastern elongation from the Sun on November 1 and well away from the Sun for good viewing, but very low. It will brighten to magnitude -4.7 in the weeks ahead and grow into a large, thinning crescent nearly an arcminute across by New Year’s Day. It will be the perfect Christmas Star and will make several beautiful pairings with the crescent Moon.

Mars: This inspiring, rusty world has an off year as it remains on the far side of the Sun hardly appearing any larger than Uranus at less than 6 arcseconds across. It will grow slightly larger by the end of the year as it heads for a fair opposition on April 8, 2014.

Jupiter: This huge, stormy world is always very large and rewarding with active cloud belts and spots, but it will be primarily a winter planet for a few more years. Jupiter begins the year well up in the south during the early evening offering the opportunity to follow it through one full rotation during the long winter nights since it rotates in just less than ten hours while night lasts up to 15 hours. It will eventually become lost in the evening twilight by April as it fades to magnitude -2.0 and shrinks to 33 arcseconds across. Jupiter rises before midnight by November and is at opposition on January 5, 2014 in Gemini when it will be 46.8 arcseconds across and blaze at magnitude -2.7. The large size will allow for detailed viewing of the cloud belts, polar hoods, and Great Red Spot. It should be possible to see the tiny discs of the larger moons, Callisto and Ganymede, and to compare their size to smaller Europa and Io. It might even be possible to detect slight color differences among them.

Saturn: This beautiful, ringed world continues to dominate another year of star parties as the rings continue to open revealing finer detail than in any year since 2005. Saturn is at opposition on April 28 in Virgo when it will be 18.9 arcseconds across and shine at magnitude +0.1. There is always much to see and just looking at Saturn and admiring its beauty is satisfying. The warmer seasons will allow excellent chances to study Saturn’s belts and spots and to look for the Cassini Division in the rings. The largest moon, Titan, is usually visible and it might be possible to see a little peach coloring to it. Saturn will slowly fade to magnitude +0.8 and shrink to around 16 arcseconds across in October when it becomes lost in the evening twilight.

Uranus: This mysterious, misty world will be at opposition on October 3 in Pisces. Uranus will be 3.7 arcseconds across and shine at magnitude +5.7 to the lower left of the Great Square of Pegasus and well east of the Circlet of Pisces just above Cetus.

Neptune: This energetic, windy world is at opposition on August 26 in Aquarius below the Water Jar. Neptune will be 2.4 arcseconds across and shine at magnitude +7.8. A finder chart for Uranus and Neptune will appear in the August issue of Telescopic Topics. Both planets will rise before midnight by August and gradually fade into the evening twilight by February 2014.

Pluto: This dark, frigid world is finally coming out of the thick of the heart of the Milky Way above the spout of the Sagittarius Teapot, but will remain a challenge to find. Pluto is at opposition on July 1 among thousands of stars and will shine like a faint spark at magnitude +14.0 and will be only 0.1 arcseconds across. Locating Pluto will gradually become easier in the years ahead as it leaves the heart of the Milky Way by 2015 and crosses the ecliptic in 2018, but will grow slowly fainter and lower in declination for the rest of our lives as it moves steadily away from Earth.