Copyright © 1993 by James V. Scotti (Spacewatch, Arizona)
This image of periodic comet Howell was obtained by J. V. Scotti during the 1993 apparition.
Howell (California Institute of Technology, California, USA) discovered
this comet on photographic plates obtained with the 0.46-m Schmidt
telescope at Palomar Observatory on 1981 August 29.35. She estimated
the total magnitude as 15. Howell confirmed the discovery on August
30.37. The comet was described as diffuse and tailless. It was then
located in Cetus.
Following the acquisition of further observations during the 1981 discovery apparition, B. G. Marsden computed two orbits which
he published on IAU Circular 3635 (1981 September 8). One was parabolic with a perihelion date of 1982 April 13.47, while the second was an elliptical orbit with a perihelion date of 1981 May 19.31 and an orbital period of 7.28 years. Marsden said he preferred the elliptical orbit. The elliptical orbit was confirmed on September 11 when Marsden published a revised orbit on IAU Circular 3636. This orbit had a period of 5.94 years and indicated the comet had passed 0.6 AU from Jupiter during 1978.
The comet reached a maximum magnitude of about 12 during its 1987 apparition.
The comet reached its most southerly declination of -7 degrees at the end of 1998 February and passed 1.066 AU from Earth during mid-May. This was the closest approach of this apparition. Perihelion (point closest to the sun) came on September 27 (1.406 AU). Observers watched the comet steadily brighten and by October and November brightness estimates placed the comet around magnitude 10.5. The coma was then between 3 and 5 arc minutes across.
Copyright © 1998 by Michael Jäger
This image was taken by Michael Jäger on 1998 December 15.69. He used a 0.25-m Schmidt camera. Exposure time was 8 minutes and the photographic emulsion was Kodalith (ORTHO). Jäger determined the magnitude as 10.8. The image was cropped by the webmaster to save space. (Thanks to Gerald Rhemann for permission to use this image.