In the previous article we left our asteroid hunting champion out in the field with another asteroid in his bag. It was an exciting hunt as he hopped from star to star in an unknown patch of sky and the Asteroid Hunter was rewarded for his effort. The question is: “What can he do now that he has confirmed seeing another one?”
Once an asteroid is confirmed, it can be followed and plotted for several nights. It is not necessary to view it more than two different nights, but if the asteroid is a tumbler, it might be possible to see fluctuations in its magnitude. It is also fun to watch it move between stars and create little patterns. Once all of the information is logged and the asteroid’s positions are plotted in the field, the next step is to officially log the asteroid and neatly replot it on a clean sheet of paper or notebook. The Asteroid Hunter uses circles of at least 2” in diameter on a clean sheet of paper to represent the field of view and very carefully plots all of the stars seen through the telescope. The asteroid is added to the same sketch for each night it is seen so that its motion can be detected and its position should be labeled with the date and time for each night observed. The stars are colored black and the asteroid is colored red so that it can be easily distinguished from the stars. Additional information should be added such as the magnification used and specifics about the asteroid such as its name, size and magnitude. As an added measure, a sketch of the constellation where the asteroid was found could be added on the same page showing its location and direction. The pages can be assembled into a binder that will eventually become full of asteroid sketches and data, a treasured trophy.
Are asteroids really nothing more than points of light through a telescope? Ceres is the largest asteroid at 605 miles in diameter and under the very best conditions when it is closest to Earth it can be as large as 0.8 arcseconds across. This means that anyone with a telescope of 12” or larger under perfect seeing conditions should theoretically see a disc. The MVAS Apollo Observatory’s 16” Meade Schmidt Cassegrain telescope should be able to resolve Ceres into a tiny disc during favorable oppositions, but one might be unconvinced. A photograph resolving it into a disc would be a trophy of accomplishment. Ceres is an excellent beginner’s asteroid because it becomes quite bright, often reaching magnitude +7.0, which makes it readily visible through binoculars. Giuseppe Piazzi discovered Ceres, on January 1, 1801. Initially thought to be a planet, it was named after the goddess of grain (cereal). With more discoveries it was later classified as the largest asteroid. In 2006, it once again gained planet status as a dwarf planet.
Another excellent asteroid to begin with is Vesta. It was discovered by Heinrich Olbers in 1807 and is the 4th asteroid discovered. At 360 miles in diameter it is too small to resolve into a disc, but it has the distinction of being the brightest of all the asteroids. At its best oppositions it can be as bright as magnitude +5.3 which means it can be seen with the unaided eye under dark skies. Vesta is also the only asteroid bright enough to trip the color receptors in the eyes revealing a warm, lemon-yellow tint. The Asteroid Hunter knows when he sees Vesta since its color gives it away.
The Asteroid Hunter’s first asteroid, Amphitrite, is also an easy catch. If anyone feels it will bring him/her the same luck eventually leading to finding 300+ asteroids like he did, then only a small telescope is required. It is rather bright for an asteroid as it can reach magnitude +9.0. Amphitrite is a fairly large asteroid about 132 miles in diameter and orbits between Mars and Jupiter around 200 million miles from the Sun. It is the twenty-ninth asteroid discovered and was found by Albert Marth in London on March 1, 1854. Amphitrite is a stony asteroid made up of silicate and nickel with a smaller amount of iron. The name is derived from a Nereid in Greek Mythology who was the wife of Poseidon and queen of the sea. Amphitrite almost ended up being the first asteroid visited by a spacecraft, but will always be remembered by space trivia buffs as the asteroid that got away. The Galileo spacecraft was supposed to fly by Amphitrite on December 6, 1986 on its way to Jupiter and would have given us the first close-up view of an asteroid. Unfortunately, the Space Shuttle Challenger disaster earlier that year postponed the launch until October 18, 1989 and the opportunity was lost. Gaspra became the first asteroid visited by a spacecraft when Galileo flew by it on October 29, 1991.
The best trophy of all is to receive a gold membership certificate suitable for framing along with a beautiful cloisonné pin by completing the asteroid observing program through the Astronomical League (http://www.astroleague.org/). Every member of the Mohawk Valley Astronomical Society has the option of being a member of the Astronomical League for an additional fee of $7.50. This is a worldwide organization promoting the interests and achievements of amateur astronomers. The goal in receiving the gold membership certificate with a pin is to observe 100 asteroids by plotting their positions on at least two nights to confirm movement. This is a challenging project with some serious plotting, but highly rewarding. If this seems too challenging, only 25 asteroids need to be plotted and confirmed to earn the regular award without the pin.
Hunting asteroids is the Asteroid Hunter’s drive and there is no stopping since that first night on January 22, 1988. It was a little slow for several years, but an upgrade to a 80mm Meade refractor in 1988 rekindled the hunt, which was followed by an upgrade to a 100mm Orion refractor in 2003. By 2009 he was catching an average of 25 asteroids per year. He became more aggressive during 1997 and caught his 50th asteroid, Anacostia, on July 24, 1998; his 100th asteroid, Doris, on September 26, 2000; his 200th asteroid, Roxanne, on July 28, 2005; and his 300th asteroid, Sarita, on September 22, 2008.
The Asteroid Hunter continues to this very day to hunt asteroids every chance he gets. Will he someday catch his 1000th asteroid? Time will tell, but in the meantime, inspired by his passion for the hunt of these tiny worlds, go out and start hunting and soon you will gain a keen appreciation of the night sky, an amateur astronomer’s ultimate trophy.