Comet 103P/Hartley 2

Comet 103P/Hartley 2 is expected to brighten to about magnitude 4.5 towards the end of October, although it will then be very low in NZ skies. During November it will get much higher as the comet moves south of equator. Although it then will have faded a magnitude, it should still be visible in binoculars. By early December it will be in the sky all the short night, but will become too faint for viewing with binoculars, requiring a small telescope.

At the end of October Hartley 2 will be in Gemini. It moves across a corner of Monoceros and into Canis Minor during the first week of November. On the 6th it will be a little under 7° from Procyon. By early December the comet's motion will have slowed, its path will curve round about 12° from Sirius.

103P/Hartley 2 was discovered photographically by Malcolm Hartley in March 1986 at Siding Spring in Australia. The reason it had not been discovered earlier lies in the fact that it made a close approach to Jupiter in 1982. The gravity of the planet changed the comet's orbit into its present one.

The distance of 103P/Hartley 2 from the Sun varies from 1.06 AU at perihelion to 5.89 Au at aphelion. Its period is 6.47 years.

---

Chart prepared using GUIDE 8.0. Program produced by Project Pluto.

---

Positional data for 103P/Hartley from August to December 2010.

The table shows the position of the comet , its distance in AU from the Sun and Earth, its magnitude, elongation from the Sun, the constellation it is in and the approximate rise and set times at Wellington. Times will differ by a few minutes at other places in NZ.

In August and September the comet is well north of the equator and will be very low in NZ skies, eventually not rising at all. When it reappears in NZ skies in late October it will set after sunrise. The comet will then move quite rapidly to the south so that towards the end of the year it will also rise before sunset, so be in NZ skies all night.

      Date         RA      Dec    Sun    Earth   Mag   Elong   Con    Rise   Set
                hr min    deg  '   AU     AU            deg            pm     am
   23 Aug 2010  22 42.8   +33 42  1.379  0.468  10.0   134.1   Peg    9:17   4:37  NZST
   30 Aug 2010  22 48.9   +37 08  1.323  0.406   9.3   133.7   Lac    9:18   3:53  NZST
    6 Sep 2010  22 57.5   +40 46  1.271  0.349   8.6   132.8   Lac    9:28   3:05  NZST
   13 Sep 2010  23 10.7   +44 38  1.223  0.297   7.8   131.5   And    9:55   2:09  NZST
   20 Sep 2010  23 32.7   +48 47  1.179  0.248   7.1   130.0   And   11:16  12:37  NZST 
   27 Sep 2010  00 11.4   +53 05  1.141  0.204   6.3   128.5   Cas     Does not rise
    4 Oct 2010  01 21.3   +56 27  1.108  0.166   5.6   127.3   Cas     Does not rise     
   11 Oct 2010  03 11.2   +55 09  1.084  0.137   5.0   125.8   Per     Does not rise
   18 Oct 2010  05 02.8   +44 28  1.067  0.122   4.6   122.9   Aur    2:38 am NZDT
   25 Oct 2010  06 15.3   +27 32  1.059  0.125   4.5   118.3   Gem    1:13 am NZDT
    1 Nov 2010  06 55.9   +12 02  1.060  0.144   4.9   114.4   Gem   12:20 am NZDT
    8 Nov 2010  07 18.5   +00 53  1.070  0.173   5.4   113.0   CMi   11:30 pm NZDT
   15 Nov 2010  07 31.1   -06 38  1.089  0.207   5.9   113.7   Mon   10:48 pm NZDT
   22 Nov 2010  07 37.2   -11 40  1.115  0.242   6.5   115.9   Pup   10:08 pm NZDT
   29 Nov 2010  07 39.0   -14 59  1.148  0.278   7.1   119.2   Pup    9:30 pm NZDT
    6 Dec 2010  07 37.4   -17 02  1.188  0.315   7.7   123.3   Pup    8:52 pm NZDT
   13 Dec 2010  07 33.4   -18 03  1.233  0.353   8.3   127.7   Pup    8:17 pm NZDT
   20 Dec 2010  07 28.0   -18 11  1.282  0.393   8.9   132.3   Pup    7:43 pm NZDT
   27 Dec 2010  07 21.9   -17 37  1.335  0.436   9.5   136.7   CMa    7:12 pm NZDT
    3 Jan 2011  07 16.1   -16 27  1.390  0.483  10.1   140.4   CMa    6:43 pm NZDT