Mohawk Valley Astronomical Society

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Planet Watch 2005

by Perry Pezzolanella, MVAS

The evening skies will be memorable this year with many spectacular conjunctions between the planets and occasionally the crescent Moon. Mars makes a dramatic return as autumn approaches and there will be a few noteworthy comets along with countless asteroids, meteor showers, and possibly an unexpected aurora. There will be at least one bright planet in the evening sky on any given day of this year.

There are no lunar or solar eclipses during 2005. The next lunar eclipse will be a total one after sunset on March 3, 2007 and the next solar eclipse is a very slight partial, about 5%, on May 20, 2012.

The year starts off with a nice evening comet as Comet Machholz passes high up near the Pleiades during early January possibly reaching magnitude +4. A comet worth looking for is Temple 1 when it is at its brightest in Virgo near Jupiter between June 8 and 12 at magnitude +9.3. Even though this is dim, history will be made on July 4 when NASA’s Deep Impact spacecraft fires an 820-pound probe into the comet to study the resulting crater. It is worth locating for the purpose of history and to note any possible changes in brightness or appearance from the impact during the following evenings.

As 2005 begins, Saturn dominates the evening sky, but soon will be joined by Jupiter. Mercury will join them briefly during March. Venus appears later in May and then Mercury briefly appears again in June for a dramatic conjunction with Saturn and Venus on June 24. Saturn then departs the evening sky with Mercury following behind. Venus hang low in the twilight until Jupiter joins it for a beautiful pairing on September 1. Jupiter then departs, but Mars begins to blaze in the northeast before midnight and draws attention away from Venus still low in the southwest. Saturn follows Mars up into the night sky by November and the year closes with Venus preparing to disappear into the twilight. Here is the breakdown for each planet in the evening sky during 2005:

Mercury: The Copper Planet will be easiest to see in the evening sky from February 27 to March 22 with its highest point above the horizon on March 12. A perfect chance to find Mercury comes on March 11 when it is to the right of the crescent Moon. Mercury will grow steadily larger from 6 to 10 arc-seconds 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: The Silver Planet appears low in the evening sky soon after sunset by Memorial Day and dazzles for the rest of the year. It will be unusually low all year, barely rising above the treetops, but will have many nice pairings with the crescent Moon. Its magnitude will rise from -3.8 to -4.6 and its size will increase from 10 arc-seconds to nearly one arc-minute from May until the end of the year as the phase changes from nearly full to a large, thin crescent barely 6% lit.

Mars: The Red Planet returns to glory later this year bringing back memories of 2003. It will begin rising before midnight by August and will reach opposition on November 7 high up in Aries. It will actually be closest to Earth on October 30 when it is 43.1 million miles away. It will be 20.2 arc-seconds across and shine at magnitude -2.3. It will begin to grow smaller by the end of the year and fade into the twilight later in 2006, ending a trio of beautiful oppositions that began in 2001.

Asteroids: This is a perfect year to begin collecting asteroids and seven are quite bright. All that is needed is a star chart with its location and a couple of clear, moonless nights to confirm their movement. Flora is at opposition on January 14 in Gemini along with Herculina on January 16, Pallas in Virgo on March 23, Ceres in Libra on May 8, Iris in Ophiuchus on June 3, and Juno in Orion on December 9. Vesta reaches opposition during the first week of 2006 in Gemini, but ends 2005 at magnitude +6.2. The other asteroids range in brightness from magnitude +7.0 to +9.2.

Jupiter: The Beige Planet dominates spring as it rises before midnight during January and is at opposition on April 3 in Virgo not far to the upper right of Spica. It will be up all night at its largest and brightest at 44.2 arc-seconds across and magnitude -2.3. Jupiter will fade to magnitude -1.5 and shrink to 31 arc-seconds as it sinks into the twilight by September, not to reappear before midnight until next February.

Saturn: The Butterscotch Planet continues its exceptional oppositions as it remains near its closest point to Earth. Opposition is on January 13 in Gemini when it is 20.6 arc-seconds across and shining at magnitude -0.1. The rings continue to slowly close since last year, but will still give the planet a classic appearance. Saturn will gradually fade to magnitude +0.5 and shrink to 17 arc-seconds by June when it will become lost in the evening twilight. Saturn will rise in the northeast by November for the start of another great viewing season next year.

Uranus: The Turquoise Planet will be in Aquarius below the Water Jar asterism when it reaches opposition on August 31. It will be 3.7 arc-seconds across and shine at magnitude +5.7 not far to the right of the bright star Lambda Aquarii.

Neptune: The Blue Planet is at opposition on August 8 in Capricornus when it will be 2.4 arc-seconds across and shine at magnitude +7.8. It will shine between the bright stars Iota and Theta Capricorni. A finder chart for Uranus and Neptune will appear in the July issue of Telescopic Topics. Both planets will rise before midnight in July and gradually fade into the evening twilight during January 2006.

Pluto: The Mauve Planet will be a tough one to find this year as it is now beginning its decade-long trek across the Milky Way where it will surely become lost among the countless stars. It is at opposition on June 13 in Serpens Cauda when it will be 0.1 arc-seconds across and shine feebly at magnitude +13.8. Pluto will emerge on the other side of the Milky Way in 2015 within the Teaspoon asterism in Sagittarius, but first it must cross the star-studded M24, the Small Sagittarius Star Cloud, in 2009.