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C/2009 R1 (McNaught)

Orbit by Kazuo Kinoshita

Image of comet McNaught on 2010 June 8
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.

Discovery

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.

Click here for a short summary of this comet.

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 bright toward the end of June and during the first days of July. Unfortunately, it will be located in twilight during this period. Its altitude was about 15 degrees in early morning twilight on June 20. It will be barely visible in the morning and evening sky on June 25, when the altitude will only be about 6 degrees around the time of nautical twilight. The comet should be at its brightest during the period of June 30 to July 2. It 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. Although the peak brightness was expected to reach magnitude 2, based on observations made since late April, the rate of brightening has slowed during the last couple of weeks, with magnitude estimates hovering between 5 and 5.5. This currently puts the comet about 2 magnitudes behind the optimistic predictions, so that the maximum magnitude may not exceed 4.

    • Additional Images

    Image of comet McNaught on 2009 September 10
    Copyright © 2009 by E. Guido and G. Sostero (Italy)

    E. Guido and G. Sostero obtained this image on 2009 September 10.2, using a 25-cm reflector and a CCD camera located in Mayhill, New Mexico (USA). They co-added twenty 120-second exposures. This was an independent confirmation of this comet.

    Image of comet McNaught on 2010 May 21 Copyright © 2010 by Martin P. Mobberly (Cockfield, Suffolk, England)

    M. P. Mobberly obtained this image of comet McNaught on 2010 May 21.43 using a remote telescope in New Mexico. The telescope was a 25-cm Takahashi Epsilon and the camera was an SBIG ST-8XE. This was a 120 second exposure. The image is 32' wide and 21' tall.

    Image of comet McNaught on 2010 May 22 Copyright © 2010 by Martin P. Mobberly (Cockfield, Suffolk, England)

    M. P. Mobberly obtained this image of comet McNaught on 2010 May 22.44 using a remote telescope in New Mexico. The telescope was a 25-cm Takahashi Epsilon and the camera was an SBIG ST10XME. This was a 120 second exposure. The image is 30' wide and 15' tall.

    Image of comet McNaught on 2010 May 23 Copyright © 2010 by Martin P. Mobberly (Cockfield, Suffolk, England)

    M. P. Mobberly obtained this image of comet McNaught on 2010 May 23.42 using a remote telescope in New Mexico. The telescope was a 25-cm Takahashi Epsilon and the camera was an SBIG ST10XME. This was a 120 second exposure. The image is 30' wide and 15' tall.

    Image of comet McNaught on 2010 June 2 Copyright © 2010 by Martin P. Mobberly (Cockfield, Suffolk, England)

    M. P. Mobberly obtained this image of comet McNaught on 2010 June 2.41 using a remote telescope in New Mexico. The telescope was a 25-cm Takahashi Epsilon and the camera was an SBIG ST10XME. This was a 120 second exposure. The image is 36' wide and 17' tall.

    Image of comet McNaught on 2010 June 6 Copyright © 2010 by Michael Jager (Austria)

    M. Jager obtained this image of comet McNaught on 2010 June 6.02, using a 20-cm telescope. Using an SXV-H9 CCD camera, he obtained separate 70-second exposures using red, green, and blue filters and then combined the images to form the color picture above.

    Image of comet McNaught on 2010 June 6
    Copyright © 2010 by Martin P. Mobberly (Cockfield, Suffolk, England)

    M. P. Mobberly obtained this image of comet McNaught on 2010 June 6.44 using a remote telescope in New Mexico. The telescope was a 25-cm Takahashi Epsilon and the camera was an SBIG ST10XME. This was a 120 second exposure. The image is 55' wide and 27' tall.

    Image of comet McNaught on 2010 June 8
    Copyright © 2010 by Martin Gembec (Czech Republic)

    M. Gembec obtained this image of comet McNaught on 2010 June 8 using a Canon 30D and a 135mm lens. The image is a composite of 14 two-minute exposures at ISO 1600. The original image was white with black stars, but the webmaster has inverted it to make it comparable to other images on this page. The tail is about 7 degrees long.

    Image of comet McNaught on 2010 June 10
    Copyright © 2010 by Gary W. Kronk (Illinois, USA)

    G. W. Kronk obtained this image of comet McNaught on 2010 June 10 using a 8-inch Meade LX-200 and a black & white Mallincam Hyper. The image is a composite of 40 7-second exposures. Gary noted the comet was an easy object in 20x80 binoculars, with a hint of tail extending westward.

    Image of comet McNaught on 2010 June 11
    Copyright © 2010 by Martin P. Mobberly (Cockfield, Suffolk, England)

    Image of comet McNaught on 2010 June 12
    Copyright © 2010 by Dale Ireland (Silverdale, Washington, USA)

    D. Ireland obtained this image of comet McNaught on 2010 June 12 using a Nikon D90 and a Nikon 500mm lens. The image is a composite of five 3-minute exposures. Dale said the comet was then low in the northeast and was visible in binoculars.

    Image of comet McNaught on 2010 June 15
    Copyright © 2010 by Gary W. Kronk (Illinois, USA)

    G. W. Kronk obtained this image of comet McNaught on 2010 June 15 using an Orion EON 80mm Apo refractor and a Canon EOS T2i DSLR. The image is a composite of three 30-second exposures at ISO 1600. Thin clouds were drifting across the sky, which accounts for the bright star to the right having a glow surrounding it.

    Image of comet McNaught on 2010 June 17
    Copyright © 2010 by Sylvain Wallart (Pas de Calais, France)

    S. Wallart obtained this image of comet McNaught on 2010 June 16. He used an Astro-professional 80ED and a Canon EOS 450D. With the camera set at ISO 800, he obtained 12 images with exposure times up to 45 seconds.

    Image of comet McNaught on 2010 June 16
    Copyright © 2010 by Gary W. Kronk (Illinois, USA)

    G. W. Kronk obtained this image of comet McNaught on 2010 June 16 using an Orion EON 80mm Apo refractor and a Canon EOS T2i DSLR. The image is a composite of three 30-second exposures at ISO 1600. The original image is color, but since the comet did not clear the wall of my observatory until after morning twilight was beginning, I converted the image to black and white in order to increase the contrast a bit.

    Image of comet McNaught on 2010 June 17
    Copyright © 2010 by Michael Jager (Austria)

    M. Jager obtained this image of comet McNaught on 2010 June 17.02. He used a 20-cm telescope and an SXV-H9 CCD camera, and obtained separate 120-second exposures using red, green, and blue filters. They were combined to form the color picture above.

    Image of comet McNaught on 2010 June 22
    Copyright © 2010 by Valter Giuliani and Enrico Colzani (Sormano Astronomical Observatory, Italy)

    V. Giuliani and E. Colzani obtained this image of comet McNaught on 2010 June 22.17. They used a 115-mm APO refractor and an SBIG STL-11000M CCD camera to obtain this 150-second exposure.

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