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Hale-Bopp: The Great Comet o
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| Title |
Hale-Bopp: The Great Comet of 1997 |
| Explanation |
Ten short years ago, Comet Hale-Bopp [ http://www.cometography.com/lcomets/1995o1.html ] rounded the Sun and offered a dazzling spectacle in planet Earth's night. This stunning view [ http://www.astropix.com/HTML/SHOWCASE/970401.HTM ], recorded shortly after the comet's perihelion passage on April 1, 1997, features the memorable tails [ http://www.ifa.hawaii.edu/~jewitt/tail.html ] of Hale-Bopp -- a whitish dust tail and blue ion tail. Here, the ion tail extends well over ten degrees across the northern sky, fading near the double star clusters [ http://antwrp.gsfc.nasa.gov/apod/ap060413.html ] in Perseus, while the head of the comet lies near Almach [ http://www.astro.uiuc.edu/~kaler/sow/almach.html ], a bright star in the constellation Andromeda. Do you remember Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap970416.html ]? The photographer's sons do, pictured in the foreground at ages 12 and 15. In all, Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap970328.html ] was reported as visible to the naked eye from roughly late May 1996 through September 1997. |
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Comet Hale-Bopp Fades
| Title |
Comet Hale-Bopp Fades |
| Explanation |
Comet Hale-Bopp has faded in the past few weeks. For Hale-Bopp [ http://newproducts.jpl.nasa.gov/comet/ ], promised as the Great Comet of 1997, this was a bit of a disappointment -- but not entirely unexpected. Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap960729.html ] continues to approach the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap960916.html ] - making the comet itself brighten, but now the Earth [ http://antwrp.gsfc.nasa.gov/apod/ap960819.html ] is moving away from it - making the comet appear to dim. Experts disagree on just how bright Hale-Bopp [ http://encke.jpl.nasa.gov/hale_bopp_info.html ] will become. Optimists hope it will eventually outshine Comet Hyakutake [ http://antwrp.gsfc.nasa.gov/apod/lib/hyakutake.html ], but some pessimists now expect no better than 3rd magnitude - hardly visible from well-lit cities [ http://antwrp.gsfc.nasa.gov/apod/ap960617.html ]. Comet Hale-Bopp [ http://www.eso.org/comet-hale-bopp/ ] still appears to be, however, a very large comet, and is sure to show much activity as it nears the Sun. The comet should reach peak brightness in March 1997. [ http://newproducts.jpl.nasa.gov/comets/ephemjpl3.html ] This image [ http://www.eso.org/comet-hale-bopp/comet-hale-bopp-summary-sep13-96-rw.html ] was taken on August 18th and shows gas shed from the nucleus of the comet. |
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A Hale-Bopp Triple Crown
| Title |
A Hale-Bopp Triple Crown |
| Explanation |
It was truly a busy sky. In one of the more spectacular photos yet submitted to Astronomy Picture of the Day [ http://www.phy.mtu.edu/apod/ ], Don Cooke of Lyme, New Hampshire [ http://www.state.nh.us/soiccnh/lyme.htm ] caught the Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ], Moon [ http://antwrp.gsfc.nasa.gov/apod/lib/moon.html ], Earth [ http://antwrp.gsfc.nasa.gov/apod/ap970130.html ], night sky [ http://antwrp.gsfc.nasa.gov/apod/ap970403.html ], Pleiades star cluster [ http://antwrp.gsfc.nasa.gov/apod/ap960903.html ], and Comet Hale-Bopp [ http://www.jpl.nasa.gov/comet/ ] all in one frame. The first leg of this "triple crown" exposure was of the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap960518.html ], taken at 6:55 pm on April 10th 1997. Through a dark filter, the Sun [ http://antwrp.gsfc.nasa.gov/apod/lib/sun.html ] appears as the bright dot on the lower right of the image. A second filtered exposure was then taken after the Sun had set, one hour and 40 minutes later - this time featuring the Moon [ http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-moon.html ]. The Moon appears as a crescent superimposed on an odd-shaped dark circle protruding into the left of the image. This shadow is actually a silhouette of a driveway reflector mounted on an aluminum rod used to block out the bright moon - so as to allow a third exposure, this time unfiltered, of the background night sky. And what a beautiful sky it is. Highlights include Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap970610.html ], on the right, and the Pleiades star cluster [ http://www.seds.org/billa/twn/m45x.html ], near the center. But what, you may wonder, is that bright light near the center of the picture? Don't worry if you can't guess: it's a porch light from a house across the river! |
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Hale-Bopp: A Continuing Tail
| Title |
Hale-Bopp: A Continuing Tail |
| Explanation |
Where is Hale-Bopp now? The Great Comet of 1997 [ http://www.jpl.nasa.gov/comet/ ], one of the largest and most active comets ever, is outbound [ http://antwrp.gsfc.nasa.gov/apod/ap970910.html ] about 400 million miles from the sun. Too faint for viewing without telescopes or binoculars, Hale-Bopp is presently positioned in the very southerly constellation of Pictor. This "negative" image [ http://www.eso.org/outreach/press-rel/pr-1998/phot-05-98.html ] (black stars against white sky) of Hale-Bopp is the result of a 1 hour time exposure using the 1-metre European Southern Observatory [ http://search.eso.org:8080/lasilla/generalinfo/html/aboutls.html ] Schmidt telescope on January 5. Clearly the comet still has a substantial tail [ http://antwrp.gsfc.nasa.gov/apod/ap971215.html ], blown by the solar wind [ http://antwrp.gsfc.nasa.gov/apod/ap970217.html ], that points generally away from the sunward direction. But look closely. A spiky "anti-tail" is also visible [ http://cfa-www.harvard.edu/iauc/06800/06812.html ] pointing toward the sun! It is likely that this anti-tail is composed of dust grains released from the comet nucleus [ http://antwrp.gsfc.nasa.gov/apod/ap961210.html ] which are too large to be easily pushed by the solar wind. As Hale-Bopp recedes [ http://www.pha.jhu.edu/~weaver/hb_stis.html ] from the sun its activity will subside but astronomers are still uncertain as to how long its tails will last. After a swing through the outer solar system and the Oort cloud [ http://www.windows.umich.edu/comets/Oort_cloud.html ], Hale-Bopp will pass through the inner solar system again ... around the year 5400. |
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Hale-Bopp: The Crowd Pleaser
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| Title |
Hale-Bopp: The Crowd Pleaser Comet |
| Explanation |
In 1997, the bright comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap970320.html] may have become the most viewed comet in history [ http://medicine.wustl.edu/~kronkg/past_comets.html ] -- visible even to casual skywatchers in light polluted [ http://antwrp.gsfc.nasa.gov/apod/ap970830.html ] cities around [ http://antwrp.gsfc.nasa.gov/apod/ap970408.html ] the globe [ http://antwrp.gsfc.nasa.gov/apod/ap970515.html ]. In this picture, taken by photographer Joe Orman [ http://members.home.com/rmscott/orman_index.html ] on the evening of May 8, 1997, Hale-Bopp easily competes with near twilight skies and a shining, over-exposed, crescent moon above Mobile, Arizona, USA. Where is Hale-Bopp now [ http://www.jpl.nasa.gov/comet/ ]? Still visible [ http://encke.jpl.nasa.gov/whats_visible.html ] to telescopic observers in the Southern Hemisphere, the comet is outbound [ http://antwrp.gsfc.nasa.gov/apod/ap970910.html ], presently about 537 million miles from the Sun. (Jupiter orbits at about 480 million miles.) The long lead time provided by the early discovery of Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap950820.html ] has allowed extensive observing campaigns [ http://www.eso.org/outreach/info-events/hale-bopp/ report-rw-hbitp98.html ] producing a bonanza of information [ http://www.jpl.nasa.gov/comet/news102.html ] about this primordial chunk of our Solar System [ http://stardust.jpl.nasa.gov/comets/comets.html ]. |
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The Dust and Ion Tails of Co
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| Title |
The Dust and Ion Tails of Comet Hale-Bopp |
| Explanation |
In 1997, Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_ts?Bopp ]'s "intrinsic" brightness exceeded any comet since 1811 [ http://cometography.com/lcomets/1811f1.html ]. Since it peaked on the other side of the Earth's orbit, however, the comet "appeared" only brighter than any comet in two decades [ http://cometography.com/lcomets/1975v1.html ]. Visible above are the two tails [ http://antwrp.gsfc.nasa.gov/apod/ap960502.html ] shed by Comet Hale-Bopp [ http://www.jpl.nasa.gov/comet/ ]. The blue ion tail [ http://www-spof.gsfc.nasa.gov/istp/events/halebopp/disconnect/ ] is composed of ionized [ http://csep10.phys.utk.edu/astr162/lect/light/ionization.html ] gas molecules, of which carbon monoxide [ http://www.cpsc.gov/cpscpub/pubs/466.html ] particularly glows blue when reacquiring electrons [ http://www-spof.gsfc.nasa.gov/Education/welect.html ]. This tail [ http://antwrp.gsfc.nasa.gov/htmltest/gifcity/comet.html ] is created by the particles from the fast solar wind [ http://antwrp.gsfc.nasa.gov/apod/ap000318.html ] interacting with gas from the comet's head. The blue ion tail [ http://antwrp.gsfc.nasa.gov/apod/ap970514.html ] points directly away from the Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ]. The light colored dust tail [ http://antwrp.gsfc.nasa.gov/apod/ap970403.html ] is created by bits of grit that have come off the comet's nucleus [ http://antwrp.gsfc.nasa.gov/apod/ap000805.html ] and are being pushed away by the pressure of light [ http://antwrp.gsfc.nasa.gov/apod/ap000526.html ] from the Sun. This tail points "nearly" away from the Sun. The above photograph [ http://www.celestialimage.com/page101.html ] was taken in March 1997. |
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Comet Hale-Bopp Over the Sup
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| Title |
Comet Hale-Bopp Over the Superstition Mountains |
| Explanation |
Four years ago, Comet Hale-Bopp [ http://galileo.ivv.nasa.gov/comet/ ] was discovered [ http://antwrp.gsfc.nasa.gov/apod/ap950820.html ] out near Jupiter [ http://www.seds.org/nineplanets/nineplanets/jupiter.html ] falling toward the inner Solar System [ http://spacelink.nasa.gov/Instructional.Materials/Curriculum.Support/Space.Science/Our.Solar.System/.index.html ]. Two years ago, it provided spectacular pictures [ http://antwrp.gsfc.nasa.gov/cgi-bin/cossc/apod_search?Hale-Bopp ] as it neared its closest approach to the Sun [ http://shutter.vet.ohio-state.edu/astronomy/faq/index.htm ]. Still today, spectacular pictures [ http://antwrp.gsfc.nasa.gov/apod/ap970723.html ] of the brightest comet of the 1990s are surfacing. Above, Comet Hale-Bopp was photographed in 1997 behind the Superstition Mountains [ http://www.goodnet.com/~rfidler/Page/Superstitions.htm ] in Arizona [ http://www.state.az.us/ ]. Clearly visible are the comets white dust tail [ http://antwrp.gsfc.nasa.gov/apod/ap960326.html ] that shines by reflected sunlight, and the blue ion tail [ http://antwrp.gsfc.nasa.gov/apod/ap970514.html ] that shines by glowing gas. Currently, there are several comets visible [ http://comets.amsmeteors.org/comets/current_comets.html ] from the proper location with a small telescope. A comet visible to the unaided eye [ http://encke.jpl.nasa.gov/bright_comet.html ] appears about once every five years. |
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