Harvard's IAU

Comment on the 1993 Observation of C/1995 O1 (Hale-Bopp), by Brian G. Marsden
21 January, 1996

• The problem with fitting the comet's orbit seems to be that the excess weight of the 1995 data (more than 700 observations) can throw a large residual into the single 1993 position, presumably because of systematic errors in the GSC reference-star system. By substantially reducing (e.g., by a factor of ten) the relative weight of the 1995 data, it is possible to fit the 1993 position completely satisfactorily.