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Image near dusk, with telescope and comet watcher Jocco Crawford in the foreground. Moonlight glow and lights from Austin, Texas light the horizon. The streak below the comet is an eastbound airplane.
Exposure is 1 min. on ASA 3200 TMax, 50 mm f/1.4, March 25 at circa 0200 UT.
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Hyakutake with Big Dipper. At this time the tail streached 80 degrees, all the way into Corvus.
Exposure is 1 min. on ASA 3200 TMax, 50 mm f/1.4, March 25 at circa 0730 UT
Our word COMET comes from the Greek name "kometes (aster)," meaning "long-haired (star)". Most comets are only visible with telescopes or binoculars, and appear as NEBULAE, hazy patches of light, or "fuzzballs" as astronomers unofficially call them. The faint fuzzball, which is called a COMA (= hair in Latin) may have a bright starlike concentration in the center. If the comet gets closer to the Earth (so it appears larger) or to the sun (so it becomes brighter) the fuzzball becomes visible without a telescope. When it is closer to the sun, whose heat generates the coma, a TAIL may also appear. The tail is part of the coma blown away from the sun by the SOLAR WIND, which is a flow of superheated gas expelled by the sun. (When this wind penetrates to the Earth's atmosphere it crashes into it, producing the AURORA, the Northern and Southern Lights.) The comet's tail points away from the sun. It is usually much fainter than the coma, but may have varied and amazing structure. It may appear as a single beam of hazy light, a narrow line, several beams or arcs, or a combination of all of these with appearances of waves and knots, like clouds or rushing water, but motionless, frozen in the night. The overall appearance of a great comet is of a star, standing out among all the other stars, though it be not so bright itself, because it has this faint but glorious decoration streaming from it. Photographers, in their bid to capture the tail, lose the striking contrast betreen the "star" and its "hair".
Comet Hyakutake appeared from very dark skies like a great ball of light, larger than the moon appears, when it passed the earth on March 25, and had an easily visible tail that looked like a searchlight beam. Some observers could definately see the tail stretching from the Comet's head near the handle of the Big Dipper all the way into Corvus, nearly 90 degrees away, though most lost the tail 60 degrees away in the GEGENSCHEIN, a faint patch of light created by interplanetary dust. The coma was noticeably green. All these phenomena, though easily seen, were tenuous - stars could be easily seen through all parts of the comet, which heightened it's beauty. Very little , however, could be seen in the cities, where artificial lighting washed out (along with 99% of the stars) the tail and much of the coma, leaving many to wonder what the travelling few were talking about. Amateur and professional telescopes alike showed a striking bright area in the center of the coma formed by sunward jets and the bright plasma stream that formed the root of the tail.
Links to:
"What is a Comet"My Comet Hyakutake Information
Comet Hyakutake press information