The application of Finson-Probstein dynamical theory to the dust tail of P/Halley

Large-scale images of P/Halley, taken with the UK Schmidt telescope during the period 1985 November to 1986 July, are described. Using Finson–Probstein dynamical theory, dates of major emission times are calculated and compared with dates of reported outbursts. The average duration of these emission times is 2±0.5 day. Dust grain sizes observed in the main tail range from sub-micron to micron sizes. The antitail, seen during February, gives a lower limit ($$\approx120\mu\text m$$) to the maximum grain size detectable using the Schmidt plates. There is evidence for very small (<1 μm) and/or low density grains ( 10 μm (assuming ϱ = 1 g cm⁻³ and neglecting grains ≪ 1 μm) move into elliptical orbits, thus contributing to the zodiacal cloud.