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Comet Holmes (17P/Holmes)
Comet Holmes Fades (Nov. 26, 2007)
A month after the largest known comet outburst ever (an increase in brightness from magnitude 17 to 2.8—a factor of about a half-million), Comet Holmes is now fading from view, difficult to see with the naked eye, but visible in binoculars. The comet is still reflecting considerable amounts of sunlight, but its dust cloud has
spread out to more than 870,000 miles wide. (That's still bigger than the sun at 865,370 miles in diameter.) The
distance means the light reflecting off the dust cloud is too diffuse to retain its earlier brightness. Maybe Comet Holmes will surprise us again, before it fades away completely.
Comet Holmes Bigger than the Sun (Nov. 16, 2007)
Comet Holmes is now the largest single object in the solar system—bigger than the sun!
Periodic Comet Produces Naked-Eye Outburst
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Comet 17P/Holmes.
14" LX200R at f/6.3, Canon 20dH, 2-second exposure. Oct. 25, 2007, 19:30 MST, Sierra Vista, Arizona.
Image by Rich Swanson.
© 2007 Rich Swanson |
After the HAC meeting of October 26, 2007, the public was invited to get a close-up view of
Comet 17P/Holmes (pictured above). The periodic comet experienced a dramatic outburst Wednesday, October 24. Everyone was impressed that we could see the comet naked-eye with a
near-full moon shining brightly, and with the horrendous city and college campus light-pollution.
Everyone was enthusiastic about being able to observe this comet in the coming weeks and months
under dark Arizona skies!
Comet Images
Nov. 1, 2007
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| (Above) Comet Holmes (17P) Nov. 1, 2007, 04:05 UT (21:05 MST). FOV 161 arcmin x 107 arcmin, Canon 20Da, Pronto Scope: 70mm aperture, 480mm F.L., f/6.8. Image by Doug Snyder. © 2007 Doug Snyder |
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(Above) Comet Holmes (17P) Nov. 1, 2007, 20:30 MST, with star magnitudes labeled. See table, below,
for star names. Meade AR-6 Refractor, f7/f6.3 reducer, Canon 20dH at 30 seconds. Click image or
here for
large resolution (1577x1051)). Image by Rich Swanson. © 2007 Rich Swanson
| Magnitude |
Star |
| 7.5 Mag |
HIP 17476 |
| 10.7 Mag |
TYC 3321-759-1 |
| 11.6 Mag |
TYC 3312-118-1 |
| 12.7 Mag |
USNO J0344231+503443 |
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| (Above) Comet Holmes captured on Nov. 1, 2007, as it passes in front of several stars. Image by Dennis Whitmer. Click on image or here for a larger image (640 x 512). © 2007 Dennis Whitmer |
General Information
Sky Chart
 Sky & Telescope Comet Holmes Observing Page
Periodic Comet 17P/Holmes is located in east-central Perseus. The finder chart (above) shows the northeastern horizon. The comet is easier to spot later in the evening when Perseus is higher, but before the moonrise, or after the moonset.
Look for a fuzz ball near Mirfak. (Click image or here for a large, high-res image (1600x1600)).
Detailed Sky Map (click here).
NASA JPL 3-D Orbit (click here).
Comet Holmes Path, November 2007 to March 2008 (below)
Monday, Nov. 19, 2007, is a good night to observe Comet Holmes. The comet will sail by the star Mirfak (α Persei) and appear to consume it—a sight worthy of observation. (Click on image, above, or here for a larger version (640x864).)
Holmes Discovery, History, and Additional Images
http://www.cometography.com/pcomets/017p.html
Technical Information
Recent Comet Brightnesses
http://cfa-www.harvard.edu/icq/CometMags.html
Ephemeris
http://cfa-www.harvard.edu/iau/Ephemerides/Comets/0017P.html
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Detailed Sky Map (click here)