• Nederlandstalig (Dutch): Komeet Ikeya-Zhang

  • Comet Ikeya-Zhang Photo Gallery
  • Daily ephemeris
  • Gary W. Kronk's Cometography: Comet C/2002 C1 Ikeya-Zhang
  • Royal Observatory Greenwich: Comet Ikeya-Zhang
  • JPL: Comet Observation Home Page

    * * * SKY & TELESCOPE's SKYWATCHER'S BULLETIN - May 7, 2002 * * *


    The comet is now between 5th and 6th magnitude as it continues its trek from Draco to Hercules. For a table and chart showing the comet's current location, click here.

    What's Up in Space -- 21 Apr 2002


    Although Comet Ikeya-Zhang is approaching our planet, it is also fading as it recedes from the Sun. Astronomer Clay Sherrod reports on April 18 that "Ikeya-Zhang is just visible to the naked eye and has dimmed almost one-half magnitude since April 12." Nevertheless, there's still time to see the comet before it vanishes. Get up before dawn any morning this week and look north between the constellations Cassiopeia and Cygnus; the comet is a fuzzy blob about as bright as a 4th magnitude star.

    What's Up in Space -- 8 Apr 2002


    Comet Ikeya-Zhang, which delighted evening sky watchers last week when it glided by the Andromeda Galaxy, is now visible in the morning sky, too. One of the most photogenic comets in recent memory, Ikeya-Zhang is glowing like a 3rd magnitude star with a long blue tail. You can find it yourself above the northeastern horizon before sunrise; look near the W-shaped constellation Cassiopeia.

    Photo: Marco Verstraaten, The Netherlands

    April 7, 2002


    Northern sky watchers enjoyed a rare treat just after sunset from April 3rd - 5th. As the sky faded to black, Comet Ikeya-Zhang and the great Andromeda Galaxy met barely a degree apart in the western sky. The pair, which are dimly visible to the unaided eye, remain close together. Use binoculars to find them not too far above the western horizon. In The Netherlands Marco Verstraaten of AstroPAge took this stunning picture of the comet and the galaxy using a f5.6/300mm telephotolens piggybacked on his telescope. Exposure: 4 minutes on Fuji 400.

  • Finder chart April 4
  • Finder chart April 3 (detail)
  • Finder chart April 4 (detail)
  • Finder chart April 5 (detail)

    * * * SKY & TELESCOPE's SKYWATCHER'S BULLETIN - April 2, 2002 * * *


    Mark Thursday, April 4th, on your calendar. That evening, weather permitting, look low in the northwest after sunset to spot Comet Ikeya-Zhang very near the Andromeda Galaxy (M31). The view through binoculars or a small telescope should be especially rewarding, as these two celestial spectacles crowd into the same field of view. More information about the comet, charts showing you where to look, and a link to our interactive sky chart that will illustrate the comet's position through May, is available on our Web site.

    Space Weather News for March 31, 2002


    Got dark skies? Can you see the western horizon? If you answered "yes" to both these questions, then you could be in for a treat just after sunset on April 4th. As the sky fades to black, Comet Ikeya-Zhang and the great Andromeda Galaxy will meet about 10 degrees above the western horizon. The pair will be dimly visible to the unaided eye -- even so, binoculars are recommended. Visit for finder charts and other details...

    Image of Comet Ikeya-Zhang on the evening of
    Thursday, March 22, 2002, taken by the
    MicroObservatory telescope in Cambridge.

    Harvard-Smithsonian Center for Astrophysics

    March 22, 2002

    See a Comet Tonight

    Cambridge, MA - The brightest comet since 1997's Hale-Bopp is currently gracing the western skies of North America. Comet Ikeya-Zhang (pronounced "ee-KAY-uh JONG") was discovered on February 1st by two amateur astronomers in Japan and China, respectively. Calculations of the comet's orbit by Brian Marsden of the Harvard-Smithsonian Center for Astrophysics show that it was last seen in 1661. This makes Ikeya-Zhang the first long-period comet (a comet with a period longer than 200 years) to be identified on its return to the inner solar system.

    No telescope is necessary to look at this beautiful visitor as it swings around the Sun and heads back to deep space. The comet has brightened to naked-eye visibility, but is easiest to see through binoculars. A casual glance will show the bright, starlike nucleus surrounded by a fuzzy cloud of dust and gas called the coma. The comet's tail streaks away from the Sun, pointing nearly straight up from the horizon.

    To find Comet Ikeya-Zhang, look in the western sky shortly after sunset. A red point of light about 18 degrees up in the sky is the planet Mars. (An outspread hand at arm's length covers about 15 degrees, so Mars is a bit higher than one hand-span.) To the right of Mars are two bright stars in a nearly vertical line. The comet is at the same height as Mars, to the right of the two bright stars about as far again as the distance from Mars to the stars.

    Headquartered in Cambridge, Massachusetts, the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists organized into seven research divisions study the origin, evolution, and ultimate fate of the universe.

    * * * * SKY & TELESCOPE's WEEKLY NEWS BULLETIN - March 22, 2002 * * * *


    As Comet Ikeya-Zhang (C/2002 C1) begins the outbound leg of its journey around the Sun, questions remain as to how bright it will ultimately become or whether it has already peaked. The coming week will be a crucial one in determining its brightness during the remainder of March and the first half of April....

    If it follows the path of a power-law formula, Comet Ikeya-Zhang will rise only a couple of tenths more in magnitude to attain a brightness plateau of about 3.5 that will last almost through the end of the month. However, if it exhibits an asymmetric light curve then the comet will go right on brightening and by next Friday could be brighter than magnitude 3.0 with no peak in sight....

    Full story

    What's Up in Space -- 15 Mar 2002


    Look low over the western horizon after sunset and you can spot Comet Ikeya-Zhang. The blue-tinged fuzzball is glowing like a 3.8th magnitude star in the constellation Pisces -- easy enough to see with the unaided eye from places with dark skies. The comet's tail, stretching 5 or more degrees, has been particularly photogenic -- witness the image below.

    Says astronomer Clay Sherrod: "The comet's tail will soon fade against twilight skies as the comet approaches the Sun." Indeed, the entire comet will disappear for a while around March 18th when it has a close encounter with our star. After that Ikeya-Zhang will become a pre-dawn object best seen in April.

    * * * SKY & TELESCOPE's SKYWATCHER'S BULLETIN - March 8, 2002 * * *


    Comet Ikeya-Zhang is now a naked-eye object visible low in the west as twilight fades for Northern Hemisphere observers. More information about the comet, including a graphic illustrating the comet's location after sunset and a chart showing the path of Comet Ikeya-Zhang, is available on our Web site at:

    Viewer's Guide to New Comet Ikeya-Zhang

    By Joe Rao

    08 March 2002

    A big question for skywatchers during the next couple of months is how bright the newly discovered comet, Ikeya-Zhang, will become. The answer can't be accurately predicted, but this much is nearly certain: The comet will provide an opportunity that comes along just once or twice per decade.

    Comet Ikeya-Zhang will make its closest approach to the Sun on March 18, when it will be roughly 47 million miles away or midway between the orbits of Mercury and Venus. Shortly after it was discovered on Feb. 1, it appeared there was a chance that Ikeya-Zhang might evolve into the comet of the decade, judging by an initial rapid brightening and its possible link to a spectacular 16th Century comet.

    Observations of the comet in recent days however, have tempered those initial high expectations.

    Currently, Ikeya-Zhang appears in binoculars and small telescopes with a faint and somewhat distorted bluish gas tail about 5 degrees long accompanying a sharp, well-condensed head of about fifth magnitude.

    Full story here.

    What's Up in Space -- 6 Mar 2002


    If you haven't yet seen Comet Ikeya-Zhang, now is a good time to start looking. The comet is brightening as it approaches the Sun and has lately become a naked-eye object. To find it, simply look toward the western horizon about one hour after sunset. The comet is a faint 5th-magnitude wisp slowly gliding through the constellation Pisces. Small telescopes and binoculars will reveal a lovely tail stretching 5 degrees.

    Finder Chart
    Daily ephemeris

    19 February 2002

    Newly Spotted Comet Will Soon Grace Night Skies

    By Joe Rao

    A newly discovered comet, now approaching the Sun and Earth, could develop into a relatively bright naked-eye object in coming weeks, researchers say. The best views of the comet may be reserved for those under dark skies far from bright lights, but even city dwellers should be able to spot it.

    Kaoru Ikeya of Japan and Daqing Zhang from China first sighted the comet in the constellation Cetus, the Whale, on Feb. 1. Both described it as a weak, condensed glow in their telescopes with no mention of a tail.

    The comet is called Ikeya-Zhang. The latest orbit calculation indicates it will pass closest to the Sun, a point called perihelion, on March 18 at a distance of 47.1 million miles (75.8 million km). After rounding the Sun, the comet will continue moving toward Earth, making its closest approach to our planet, called perigee, on April 28, when it will be 37.6 million miles (60.5 million km) away.

    Full story.

    SKY & TELESCOPE's AstroAlert for Comets

    February 4, 2002


    The 9th-magnitude comet spotted last week in the constellation Cetus should continue to brighten as it approaches the Sun. In early March, Comet Ikeya-Zhang could be 5th or even 4th magnitude, but it will then be very low in the western evening sky after sunset and difficult to locate. After mid-March the comet skirts north of the Sun and enters the predawn sky, where strong moonlight will hamper observations. Prospects get better during April as it draws away from the Sun and makes its way across Cygnus, but by then the comet will have started to fade.

    That's the upshot of the preliminary orbital elements calculated by Brian G. Marsden and published on IAU Circular 7813. The comet is expected to reach perihelion on March 8th at 0.49 astronomical unit from the Sun, which puts it midway between the orbits of Venus and Mercury. (For further details, and for information on how to subscribe to the International Astronomical Union's telegram service, visit

    The ephemeris below, based on Marsden's elements, gives the comet's coordinates at 0h Universal Time on selected dates along with its distance from the Earth (Delta) and Sun (r) in astronomical units, elongation from the Sun, predicted magnitude, and constellation. Since these computations are based on a very short observation interval, don't be surprised if the comet drifts off a bit after a few weeks. But the ephemeris should still give a fair idea of how the apparition will unfold.

    Be sure to check the observing section of in coming weeks for more about this object.

    As we reported in last Friday's AstroAlert, this comet was picked up visually on February 1st by Kaoru Ikeya of Shizuoka prefecture, Japan, and by Daqing Zhang in Henan province, China. Both observers described it as a small glow about 2' or 3' across, with no mention of a tail. Ikeya was using a 25-cm (10-inch) reflector, Zhang a 20-cm.

    If the name "Ikeya" rings a bell, it should. During the 1960s, Kaoru Ikeya discovered or codiscovered no less than five comets. One of them, Comet Ikeya-Seki, became the famous naked-eye sungrazer of 1965. But little had been heard from Ikeya, at least outside Japan, until he made his sixth comet discovery last week.

    "He is the phoenix!" says astrophotographer Shigemi Numazawa of Niigata, who adds that Ikeya, now age 58, is manager of the Ikeya Optical Lab, supplier of telescope mirrors to Japan's discriminating observers.

    Roger W. Sinnott

    Senior Editor
    Sky & Telescope

                     COMET IKEYA-ZHANG, C/2002 C1
     2002       RA (2000) Dec     Delta    r     Elong   Mag   Const
     0h UT      h  m      o  '     au      au      o                
    Feb  1     0 08.3   -17 50    1.335   0.951   45     8.9    Cet
    Feb  4     0 13.2   -16 22    1.293   0.899   44     8.6    Cet
    Feb  7     0 18.3   -14 46    1.249   0.847   42     8.3    Cet
    Feb 10     0 23.5   -13 04    1.202   0.796   41     7.9    Cet
    Feb 13     0 28.7   -11 13    1.153   0.746   40     7.5    Cet
    Feb 16     0 33.8   -09 12    1.101   0.698   38     7.1    Cet
    Feb 19     0 38.7   -07 01    1.046   0.651   37     6.7    Cet
    Feb 22     0 43.2   -04 36    0.988   0.608   36     6.3    Cet
    Feb 25     0 46.9   -01 58    0.929   0.570   34     5.9    Cet
    Feb 28     0 49.4   +00 57    0.868   0.537   33     5.5    Cet
    Mar  3     0 50.2   +04 09    0.806   0.512   31     5.1    Psc
    Mar  6     0 48.7   +07 38    0.746   0.496   29     4.8    Psc
    Mar  9     0 44.1   +11 21    0.689   0.491   27     4.6    Psc
    Mar 12     0 35.9   +15 14    0.638   0.497   25     4.5    Psc
    Mar 15     0 23.8   +19 09    0.594   0.513   24     4.5    Psc
    Mar 18     0 07.9   +22 56    0.559   0.539   24     4.6    Peg
    Mar 21    23 48.5   +26 25    0.532   0.572   26     4.7    Peg
    Mar 24    23 26.4   +29 27    0.513   0.611   30     4.9    Peg
    Mar 27    23 02.6   +31 56    0.501   0.654   35     5.2    Peg
    Mar 30    22 38.0   +33 52    0.494   0.700   40     5.4    Peg
    Apr  2    22 13.3   +35 15    0.492   0.749   46     5.7    Peg
    Apr  5    21 49.3   +36 09    0.493   0.799   52     6.0    Cyg
    Apr  8    21 26.1   +36 41    0.497   0.850   58     6.3    Cyg
    Apr 11    21 03.9   +36 52    0.503   0.902   64     6.6    Cyg
    Apr 14    20 42.7   +36 48    0.510   0.954   70     6.8    Cyg
    Apr 17    20 22.5   +36 31    0.519   1.006   75     7.1    Cyg
    Apr 20    20 03.1   +36 02    0.528   1.058   81     7.4    Cyg
    Apr 23    19 44.6   +35 23    0.539   1.110   86     7.6    Cyg
    Apr 26    19 26.8   +34 34    0.551   1.161   92     7.9    Cyg
    Apr 29    19 09.8   +33 37    0.564   1.213   97     8.1    Lyr
    May  2    18 53.5   +32 32    0.579   1.263  102     8.3    Lyr

    SKY & TELESCOPE's AstroAlert for Comets

    February 1, 2002


    A 9th-magnitude comet has just been found in the constellation Cetus, low in the western evening sky. It was spotted almost simultaneously on February 1st by Kaoru Ikeya of Shizuoka prefecture, Japan, and by Daqing Zhang in Henan province, China. Both observers described it as a small glow about 2' or 3' across, with no mention of a tail. Ikeya was using a 25-cm (10-inch) reflector, Zhang a 20-cm.

    The Central Bureau for Astronomical Telegrams announced the find today on IAU Circular 7812. For further details and information on how to subscribe to that service, visit

    No orbit has yet been calculated for this comet, so its future motion is anybody's guess. But Ikeya estimated it to be moving northeastward at about 10 arcminutes per hour. Shortly before 10h Universal Time on February 1st, he found its position to be right ascension 0h 08.9m, declination -17d 42' (equinox 2000.0).

    Roger W. Sinnott

    Senior Editor
    Sky & Telescope

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