Hobbies And Interests
Not All Comets Light the Sky
Comets come in all shapes and sizes, and not all of them make a spectacular appearance. When Halley's Comet came within 14 million miles of Earth in 1910, it presented a spectacular sight. Yet when it returned in 1986, it was markedly less impressive because the comet passed several times farther away from Earth. Comets are thought to originate in large numbers from two regions of the solar system: short-period comets originating from the Kuiper Belt, with a semi-major axis less than the orbit of Neptune, and orbital periods less than 200 years; and long-period comets originating from the outskirts of the solar system, in a region called the Oort Cloud, which possesses orbital periods greater than 200 years.
Understand the Components of Comets
Comets are low-density objects that are composed of a combination of water ice in addition to minor amounts of silicate materials. When comets approach the sun, the frozen ice in their composition melts and turns into water vapor. The vapor and dust becomes dislodged from the comet and streams behind it, becoming visible as the comet's tail. The bright head of the comet is called the coma, and the comet's body is often called the cometary nucleus. The meteor showers observed every year result from the Earth plowing through the debris that forms the tails of comets.
Learn Comet Nomenclature
Comet nomenclature is not as complex as it first may appear. First, the designated names contain the letters either "C," standing for long-period comets, or "P," standing for short-period comets, followed by a forward slash. Rarely, "D," which indicates a comet has disappeared or is "dead," and "X," indicating there has been insufficient evidence to compute a comet's orbit, will appear. Next comes the year of the comet's discovery, followed by a letter that indicates the month of discovery. Letters run from "A," which indicates the period from January 1 to 15, all the way to "Y," which indicates the period from December 16 to 31. Following this comes the order of discovery during the half-monthly period, then the name of the discover(s). If the comet is discovered and reported before being officially announced, up to three names can be included in its title.
Get Suitable Equipment
In order to view comets, the first thing to consider is using a good pair of binoculars or a decent telescope. A wide field of view is best for locating comets. For binoculars, it is best to have a pair with an optical value of at least 7 by 50, which have a wide field of view for locating comets. A pair of binoculars with a more powerful zoom can be used to get a better view. Telescopes with a short refractor lens measuring 3 inches or larger, or up to 4 inches to 6 inches in Newtonian manufactured telescopes, give both a combination of reasonable magnification and a wide viewing area to follow comets optimally. In contrast, telescopes with longer focal ratios generally possess narrower fields of view less suitable for observing comets.
Be Prepared
The best way to begin observing comets is to get accurate information about where and when a comet will be visible. A number of useful web sites track comets that pass close to Earth. (See Resources.) Be aware that sky glow and nearby lights can interfere with observing comets. To minimize this, try to find a suitably dark area to observe comets.