G A R Y   W.   K R O N K ' S   C O M E T O G R A P H Y


Past, Present, and Future Orbits by Kazuo Kinoshita

Sostero and Donato image of 24P exposed on 2001 April 29
Copyright © 2001 by Giovanni Sostero and Luca Donato (Remanzacco Observatory, Italy)

This image was obtained on 2001 April 29.86 with a 0.3-m f/2.8 Baker-Schmidt camera. The image was built using 4 120-second exposures obtained with a Hi-Sis 24 CCD camera.


     This comet was discovered in Virgo by Alexandre Schaumasse (Nice, France) on 1911 December 1. He estimated the brightness as about magnitude 12 and described the comet as diffuse, with a diameter of about 3 arc minutes.

Historical Highlights

  • The comet brightened to magnitude 11 during its discovery apparition as it continued to move closer to Earth. As 1912 began it was moving away from both the sun and Earth and rapidly faded. It was last seen on February 19, when the magnitude had faded below 14.
  • The comet was first recognised as moving in a short-period elliptical orbit during 1912 January, with the period then given as 7.1 years. Later calculations made after the comet was no longer visible indicated a period of 8.0 years. Several predictions were made for the 1919 return, and G. Fayet recovered the comet on 1919 October 30. It was then at magnitude 10.5 and steadily faded thereafter as it moved away from both the sun and Earth.
  • The comet reached a maximum magnitude of 12.0 during the 1927 apparition. It was then missed at the very unfavorable 1935 return.
  • The comet passed 0.37 AU from Jupiter during 1937 May which acted to increase the orbital period by 0.2 years. Searches were largely unsuccessful during the comet's expected return in 1943, but it was finally located by Henry L. Giclas (Lowell Observatory, Arizona, USA) on wide-field plates exposed on 1944 March 24. The comet was then seven degrees from its predicted position, indicating an unknown acceleration was present. This was later identified in the 1960s as a nongravitational force caused by the jet-like action of the gas rushing from the comet's nucleus.
  • The comet's next apparition came during 1951-2. This was the best observed apparition as the comet was unexpectedly bright and remained brighter than magnitude 7 from 1952 January to mid-March, and very near 6 for most of February. The coma even reached a diameter of 20 arc minutes.
  • Although the comet's 1960 return was a good one, with a maximum magnitude of 9.5, extensive searches in 1968 and 1976 revealed nothing and this puzzled astronomers. Some astronomers wondered if the unexpected increase in brightness during early 1952 indicated a problem which led to the comet's vanishing. As it was revealed in 1984, Elizabeth Roemer (Steward Observatory, Arizona, USA) found a weak, diffuse, faint smudge on a photograph exposed on 1976 December 27 which indicated a correction to the perihelion date of -0.03 day. With no confirmation the image went unannounced. As the comet approached its 1984 apparition, searches were again made. On 1984 September 5 and 6 J. Gibson (Palomar Observatory, California, USA) photographed the comet with a 1.2-m Schmidt telescope and Brian G. Marsden's subsequent orbit calculation confirmed that the 1976 object was indeed comet Schaumasse.
  • The comet's 1993 apparition was a good one, but that of 2001 is even better with the comet reaching a maximum magnitude of about 10 from late April to early June. It is then placed in the evening sky in the region of Auriga and Gemini (see chart below).
  • Close approaches to planets: This comet made 2 close approaches to Earth and 3 close approaches to Jupiter during the 20th century. It makes 2 close approaches to Earth and one close approach to Jupiter during the first half of the 21st century. (From the orbital work of Kazuo Kinoshita)
    • 0.35 AU from Jupiter on 1913 August 2
      • decreased perihelion distance from 1.23 AU to 1.17 AU
      • decreased orbital period from 8.01 to 7.94 years
    • 0.37 AU from Jupiter on 1937 May 5
      • increased perihelion distance from 1.17 AU to 1.20 AU
      • increased orbital period from 7.94 to 8.21 years
    • 0.27 AU from Earth on 1952 January 29
    • 0.98 AU from Jupiter on 1975 January 7
      • increased perihelion distance from 1.20 AU to 1.21 AU
      • increased orbital period from 8.20 to 8.23 years
    • 0.54 AU from Earth on 1993 January 27
    • 0.60 AU from Earth on 2026 January 4
    • 0.77 AU from Earth on 2034 March 19
    • 0.48 AU from Jupiter on 2044 January 16
      • increased perihelion distance from 1.19 AU to 1.21 AU
      • increased orbital period from 8.18 to 8.36 years

    Additional Images

    H. Mikuz image of 24P exposed on 1993 March 16
    Copyright © 1993 by Herman Mikuz (Crni Vrh Observatory, Slovenia)

    This image was obtained on 1993 Mar. 16.81 UT with 20-cm, f/2 Baker-Schmidt telescope, V filter and ST-6 CCD. Exposure time was 5 minutes. (The image was cropped by the webmaster and converted to black and white to save space.)

    G. Rhemann image of 24P exposed on 1993 March 20
    Copyright © 1993 by Gerald Rhemann (Austria)

    This image was obtained on 1993 March 20.92 UT with a 530mm f/3.3 Takahashi E-160. Exposure time was 40 minutes and the photographic emulsion was hypered Technical Pan 2415. The image has been cropped by the webmaster to save space.