Comet Hale-Bopp

Comet Hale-Bopp

Comet Hale-Bopp (C/1995 O1) was discovered on 23 July 1995 by two independent observers, Alan Hale (Cloudcroft, N.M.) and Thomas Bopp (Stanfield, AZ), and is showing potential of putting on a spectacular display as it nears its 1997 perihelion. The image above was taken by the Hubble Space Telescope, and shows material ejected from the rotating comet in a "pinwheel" pattern. More information on this image is available in the caption.

The nucleus of Hale-Bopp is estimated to be about 30 to 40 km across - Comet Halley's nucleus was estimated at 8 x 8 x 16 km. The nucleus is exhibiting sudden brief eruptions and a complex mottled surface. Its absolute magnitude of -1 makes it one of the brightest comets to reach the inner solar system in history. Closest approach to Earth will occurred on 22 March 1997 at a distance of 1.3 A.U. It made for a spectacular view in the March morning sky, and will be in the evening skies from mid-March to early May. Closest approach to the Sun was on 31 March at a distance of .91 A.U. The comet is estimated to have last passed by the Sun about 4200 years ago.

Hale-Bopp was visible low in the northern hemisphere pre-dawn sky in February to the ENE just below the constellation Cygnus. By the end of March the comet moved from Cygnus to Lacerta to Andromeda in the NE pre-dawn sky. The comet will be disappearing from the pre-dawn sky at the beginning of April. Since mid-March, however, the comet has also been visible in the early evening sky to the NW to WNW, at the bottom of Perseus. The comet will become higher in the sky through mid-April, and then move down towards the horizon by early May. The comet is currently one of the brightest objects in the sky and the tail is spectacular.

Information on Hale-Bopp

Perihelion distance: 0.9141 AU
Perihelion date: 01 April 1997 UT 03:19 (31 March 22:19 EST)
Closest approach to Earth: 1.3 AU
Date of closest approach to Earth: 22 March 1997
Next Perihelion: ~2380 years
Previous Perihelion: ~4200 years ago
Orbital inclination: 89.43 deg.
Orbital eccentricity: 0.9951
Argument of perihelion: 130.59 deg.
Longitude of ascending node: 282.47 deg.

Heliocentric coordinates of Hale-Bopp - for any given dates

Results of IUE and Hubble observations of Hale-Bopp - 27 March 1997

NASA plans to observe Hale-Bopp - 13 March 1997

NASA Hale-Bopp Press Release - 11 October 1995

Other Sites with Information on the Comet

The International Solar-Terrestrial Physics (ISTP) - Hale-Bopp Home Page

Observing Information - SEDS

Russell Sipes' Hale-Bopp Field Guide

Hale-Bopp and the total solar eclipse of 1997

Hale-Bopp sounding rocket missions from White Sands - Launched on March 24, 25, 29; April 5

Images of Hale-Bopp

These sites have some nice images of the comet, but nothing does justice to the real thing. For a spectacular view, find a clear view to the WNW a little after sunset (when the first stars are coming out). In the U.S., the comet will be 10 to 20 degrees above the horizon, depending on your latitude and the exact time you look. A dramatic tail extends upwards. (And it's much better than anything you'll see on the Web!)

Scienceweb - Canada

Hubble Space Telescope Images

National Astronomical Observatory - Japan

Instituto de Astrofisica de Canarias - Canary Islands, Spain

General Comet Information

Comet Fact Sheet

From the Nine Planets (SEDS, Univ. of Arizona)

From Views of the Solar System (C.J. Hamilton, Los Alamos)

Comet and Asteroid Home Page

NSSDCA Planetary Science Home Page

Dr. David R. Williams,
NSSDCA, Mail Code 690.1
NASA Goddard Space Flight Center
Greenbelt, MD 20771

NASA Official: Dave Williams,
Last Updated: 01 April 2008, DRW