NEW COMET McNAUGHT: A fresh comet is swinging through the inner solar system,
and it is brightening rapidly as it approaches Earth for a 100 million mile close encounter in mid-June. Comet McNaught (C/2009 R1) has a vivid green head and a long wispy tail that look great through small telescopes. By the end of the month it could be visible to the naked eye perhaps as bright as the stars of the Big Dipper. Because this is the comet's first visit to the inner solar system, predictions of future brightness are necessarily uncertain; amateur astronomers should be alert for the unexpected.
2010 June 7
A new comet is brightening and is now expected to become visible to the unaided eye later this month. C/2009 R1 (McNaught) is already showing an impressive tail and is currently visible through binoculars. The above image, taken yesterday from the Altamira Observatory in the Canary Islands and spanning about five degrees, shows an impressive green coma and a long ion tail in front of distant star trails. Although predicting the brightness of comets is notoriously difficult, current estimates place Comet McNaught as becoming visible to unaided northern hemisphere observers in late June, before sunrise, and in early July, after sunset. Discovered by Robert McNaught last year, the sun-orbiting iceberg will pass the Earth next week and will continue to melt and shed debris as it closes in on the Sun until early July. After reaching about half of the Earth-Sun distance from the Sun, the comet should fade rapidly as it then heads out of the inner Solar System.
THE GREAT COMET OF 2006+2007:
THIS WAS THE VIEW FROM NEW ZEALAND, TOO!!
But this is NOT the 2009 McNaught... They are TWO DIFFERENT COMETS
|C/2009 R1 (McNaught)|| |
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|Orbit by Kazuo Kinoshita|| |
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Copyright © 2010 by Francois Kugel (France)
F. Kugel obtained this image of the comet on 2010 June 8.07, as it was passing the edge-on galaxy NGC 891. He was using a 50-cm telescope and a KAI11K CCD camera. This image is the result of combining four 60-second exposures.
R. H. McNaught (Siding Spring Observatory, Australia) discovered this comet on five images obtained between 2009 September 9.62 and September 9.73. He was using the 0.5-m Uppsala Schmidt telescope and a CCD camera. The magnitude was given as 17.3-17.5. Pre-discovery images were subsequently found on images obtained at Siding Spring by McNaught and G. J. Garradd on 2009 July 20, August 1, and August 18. The magnitude was given as 18.5-18.9 on July 20. The first confirmation was obtained by astronomers at the ESA Optical Ground Station at Tenerife, Canary Islands on September 9.9. They gave the magnitude as 17.7-18.3.
Historical Highlights The first parabolic orbit was calculated by B. G. Marsden on 2009 September 10. He took 35 positions from the period spanning 2009 July 20 to September 10 and determined the perihelion date as 2010 July 2.17. The perihelion distance was given as 0.40 AU, indicating the comet could become a fairly bright object. The general correctness of this orbit was confirmed by Marsden on September 12, when he took 43 positions and again determined the perihelion date as July 2.17. The comet was ultimately found to be moving in a hyperbolic orbit, with a perihelion date of July 2.68 and an eccentricity of 1.00033.
Several observatories kept the comet under observation through the end of 2009, when it entered twilight. From the period of September through December, the comet had steadily brightened to magnitude 16.2. At the time of the final observation of 2009, the comet was still at a declination of -23 degrees.
The comet exited morning twilight around mid-March and was then magnitude 15.0-15.4. It was then at a declination of -8 degrees. Total magnitude estimates revealed the comet was brighter than 12 as April began. Visual estimates of the comet's magnitude became more plentiful as April progressed, although the comet was still only visible to observers in the Southern Hemisphere. Experienced observers gave the visual magnitude as 10-10.5 around mid-month, but found the comet brighter than magnitude 10 by month's end. The coma diameter was typically between 1.5' and 2.5' during the month.
The comet entered the skies of Northern Hemisphere observers as May began, with S. Yoshida (Gunma, Japan) spotting it with a 40-cm reflector on the 1st. At the low altitude, he noted a magnitude of 10.9 and said the coma was 1.5' across. Ten days later, K. Yoshimoto (Yamaguchi, Japan) saw the comet with his 25-cm reflector, giving the magnitude as 9.2 and the coma diameter as 3.7'. The comet developed nicely during the remainder of the month and was brighter than magnitude 7 by month's end. Estimates of the coma diameter were around 6-8' by the end of the month.
Observers were consistently estimating the comet's magnitude as bright than 6 as June began, indicating it was continuing to remain brighter than expected. Alexandre Amorim (Florianopolis,Brazil) saw the comet on June 6 using 10x50 binoculars and gave the magnitude as 5.5. The comet was then only 7 degrees above the horizon. V. Ivanov (Saratov, Russia) found the comet with the naked eye on June 12. Looking through his 20-cm reflector revealed a magnitude of 5.2, a coma 3' across, and a tail 10' long.
This comet is expected to be a bright one as June progresses. The only problem is that as it brightens it will also be sinking deeper into twilight. It will be magnitude 4 and about 20 degrees above the eastern horizon on the morning of June 15. On the morning of June 20, the comet will be about magnitude 3 and about 15 degrees above the horizon. The comet will be barely visible in the morning and evening sky on June 25, when the magnitude will be about 2.5. The altitude in the morning and evening sky might only be about 6 degrees around the time of nautical twilight. The comet will be at its brightest magnitude of about 2 during the period of June 30 to July 2. The comet would then be an evening sky object, with an altitude of about 5 degrees each day...in other words it could be very difficult to see.