Comets

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Download New Comet Data

When calculating comet positions it's important to use up-to-date orbital elements. Not only are new comets constantly being discovered, but orbital elements for comets slowly change with time, and can only be used reliably for a few weeks.

The organization responsible for coordinating new comet discoveries and producing authoritative orbital elements is the Central Bureau for Astronomical Telegrams. They kindly make these element sets available in a format directly suitable for use by a number of different astronomy programs, including SkyMap and SkyMap Pro. To download the latest element set and prepare it for use by SkyMap or SkyMap Pro, proceed as follows:

 

Downloading comet data for SkyMap Pro

  1. Follow this link to display the latest set of comet element data in SkyMap's data format.
  2. Save the page as an ASCII text file on your computer. This can have any desired name, but should have an extension of ".cat". You may wish to following the naming convention used for the files supplied with SkyMap Pro, which is to use a name of the form YYYYMMDD.cat, representing the date on which the elements were downloaded, eg "19980215.cat" for an element set downloaded on Feb 15th, 1998.
  3. Edit the file previously saved using any convenient text editor (eg Windows "NotePad"), and delete any blank lines which may be present at the beginning and the end of the file.
  4. Follow the instructions given in the SkyMap Pro manual to load the new catalog.

Note that if you are using SkyMap Pro 10 or later and are connected to the Internet, you can use the Tools/Download Data menu item within SkyMap to download up-to-date comet data at any time.

NB: The download link for comet orbital elements has changed since the program was released. If you get an error trying to download orbital elements from the program, select the "File/Preferences/Downloaded Data" menu item, and set the URL for downloading comet data to:

http://cfa-www.harvard.edu/iau/Ephemerides/Comets/Soft01Cmt.txt

Downloading comet data for SkyMap

  1. Follow this link to display the latest set of comet element data in SkyMap's data format.
  2. Save the page as an ASCII text file called "comet.sky" on your computer.
  3. Edit the file previously saved using any convenient text editor (eg Windows "NotePad"), and delete any blank lines which may be present at the beginning and the end of the file.
  4. Copy the file to the directory in which SkyMap has been installed, overwriting the previous "comet.sky" file.

When you next run SkyMap, the new orbital elements will be available for use. Note that you will have to use the Options/Comets...menu item to select the comets you wish to display on the map.

Previous Comet Orbital Elements

The files below contain sets of comet orbital element data for SkyMap and SkyMap Pro at the dates indicated, and can be used to obtain accurate comet positions for that time period. To use these orbital elements, click on a link, and then follow the procedure described above from step 2 onwards.

Orbital elements for 2008

bullet2008 May 7
bullet2008 Apr 23
bullet2008 Apr 9
bullet2008 Mar 27
bullet2008 Mar 13
bullet2008 Feb 28
bullet2008 Feb 15
bullet2008 Jan 30
bullet2008 Jan 17
bullet2008 Jan 5

Orbital elements for 2007

bullet2007 Dec 26
bullet2007 Dec 13
bullet2007 Nov 29
bullet2007 Nov 15
bullet2007 Nov 1
bullet2007 Oct 19
bullet2007 Oct 6
bullet2007 Sep 22
bullet2007 Sep 8
bullet2007 Aug 25
bullet2007 Aug 11
bullet2007 Jul 28
bullet2007 Jul 14
bullet2007 Jun 30
bullet2007 Jun 16
bullet2007 Jun 2
bullet2007 May 19
bullet2007 May 05
bullet2007 Apr 21
bullet2007 Apr 07
bullet2007 Mar 24
bullet2007 Mar 10
bullet2007 Feb 24
bullet2007 Feb 10
bullet2007 Jan 27
bullet2007 Jan 13
bullet2007 Jan 1

Orbital elements for 2006

bullet2006 Dec 23
bullet2006 Dec 09
bullet2006 Nov 25
bullet2006 Nov 11
bullet2006 Oct 28
bullet2006 Oct 14
bullet2006 Sep 30
bullet2006 Sep 14
bullet2006 Aug 28
bullet2006 Aug 13
bullet2006 Jul 31
bullet2006 Jul 14
bullet2006 Jun 30
bullet2006 Jun 14
bullet2006 May 30
bullet2006 May 14
bullet 2006 Apr 30
bullet 2006 Apr 14
bullet 2006 Mar 31
bullet 2006 Mar 11
bullet 2006 Feb 25
bullet 2006 Feb 12
bullet 2006 Jan 29
bullet 2006 Jan 14

Orbital elements for 2005

bullet 2005 Dec 31
bullet 2005 Dec 14
bullet 2005 Nov 28
bullet 2005 Nov 13
bullet 2005 Oct 31
bullet 2005 Oct 14
bullet 2005 Oct 1
bullet 2005 Sep 15
bullet 2005 Sep 1
bullet 2005 Aug 14
bullet 2005 Aug 4
bullet 2005 Jul 15
bullet 2005 Jul 3
bullet 2005 Jun 14
bullet 2005 May 30
bullet 2005 May 15
bullet 2005 May 1
bullet 2005 Apr 14
bullet 2005 Apr 1
bullet 2005 Mar 14
bullet 2005 Mar 1
bullet 2005 Feb 14
bullet 2005 Feb 1
bullet 2005 Jan 17
bullet 2005 Jan 1

Orbital elements for 2004

bullet 2004 Dec 15
bullet 2004 Dec 1
bullet 2004 Nov 1
bullet 2004 Oct 16
bullet 2004 Oct 1
bullet 2004 Sep 15
bullet 2004 Sep 1
bullet 2004 Aug 15
bullet 2004 Aug 1
bullet 2004 Jul 15
bullet 2004 Jul 1
bullet 2004 Jun 15
bullet 2004 Jun 1
bullet 2004 May 23
bullet 2004 May 1
bullet 2004 Apr 15
bullet 2004 Apr 1
bullet 2004 Mar 15
bullet 2004 Mar 1
bullet 2004 Feb 15
bullet 2004 Feb 1
bullet 2004 Jan 15
bullet 2004 Jan 1

Orbital elements for 2003

bullet 2003 Dec 15
bullet 2003 Nov 30
bullet 2003 Nov 2
bullet 2003 Oct 15
bullet 2003 Oct 4
bullet 2003 Sep 15
bullet 2003 Sep 1
bullet 2003 Aug 17
bullet 2003 Aug 1
bullet 2003 Jul 16
bullet 2003 Jul 1
bullet 2003 Jun 15
bullet 2003 Jun 1
bullet 2003 May 15
bullet 2003 May 4
bullet 2003 Apr 15
bullet 2003 Apr 1
bullet 2003 Mar 15
bullet 2003 Mar 1
bullet 2003 Feb 15
bullet 2003 Feb 1
bullet 2003 Jan 15
bullet 2003 Jan 1

Orbital elements for 2002

bullet 2002 Dec 15
bullet 2002 Dec 1
bullet 2002 Nov 15
bullet 2002 Nov 1
bullet 2002 Oct 15
bullet 2002 Oct 1
bullet 2002 Sep 15
bullet 2002 Sep 1
bullet 2002 Aug 15
bullet 2002 Aug 1
bullet 2002 Jul 15
bullet 2002 Jul 1
bullet 2002 Jun 15
bullet 2002 Jun 1
bullet 2002 May 15
bullet 2002 May 1
bullet 2002 Apr 15
bullet 2002 Apr 1
bullet 2002 Mar 15
bullet 2002 Mar 1
bullet 2002 Feb 15
bullet 2002 Feb 1
bullet 2002 Jan 15
bullet 2002 Jan 1

Orbital elements for 2001

bullet 2001 Dec 15
bullet 2001 Dec 1
bullet 2001 Nov 15
bullet 2001 Nov 1
bullet 2001 Oct 15
bullet 2001 Oct 1
bullet 2001 Sep 21
bullet 2001 Sep 1
bullet 2001 Aug 15
bullet 2001 Aug 1
bullet 2001 Jul 15
bullet 2001 Jul 7
bullet 2001 Jun 15
bullet 2001 Jun 8
bullet 2001 May 15
bullet 2001 May 1
bullet 2001 Apr 15
bullet 2001 Apr 1
bullet 2001 Mar 15
bullet 2001 Mar 1
bullet 2001 Feb 15
bullet 2001 Feb 1
bullet 2001 Jan 15
bullet 2001 Jan 1

Orbital elements for 2000

bullet 2000 Dec 15
bullet 2000 Dec 1
bullet 2000 Nov 15
bullet 2000 Nov 1
bullet 2000 Oct 15
bullet 2000 Oct 1
bullet 2000 Sep 15
bullet 2000 Sep 1
bullet 2000 Aug 15
bullet 2000 Aug 1
bullet 2000 Jul 15
bullet 2000 Jul 1
bullet 2000 Jun 15
bullet 2000 Jun 1
bullet 2000 May 15
bullet 2000 May 1
bullet 2000 Apr 18
bullet 2000 Apr 1
bullet 2000 Mar 15
bullet 2000 Mar 1
bullet 2000 Feb 15
bullet 2000 Feb 1
bullet 2000 Jan 15
bullet 2000 Jan 1

Orbital elements for 1999

bullet 1999 Dec 15
bullet 1999 Dec 1
bullet 1999 Nov 15
bullet 1999 Nov 1
bullet 1999 Oct 15
bullet 1999 Oct 1
bullet 1999 Sep 15
bullet 1999 Sep 2
bullet 1999 Aug 15
bullet 1999 Aug 1
bullet 1999 Jul 15
bullet 1999 Jul 1
bullet 1999 Jun 15
bullet 1999 Jun 1
bullet 1999 May 15
bullet 1999 May 1
bullet 1999 Apr 15
bullet 1999 Apr 1
bullet 1999 Mar 15
bullet 1999 Mar 1
bullet 1999 Feb 15
bullet 1999 Feb 1
bullet 1999 Jan 15
bullet 1999 Jan 1

Orbital elements for 1998

bullet 1998 Dec 15
bullet 1998 Dec 1
bullet 1998 Nov 15
bullet 1998 Nov 1
bullet 1998 Oct 15
bullet 1998 Oct 1
bullet 1998 Sep 15
bullet 1998 Sep 1
bullet 1998 Aug 15
bullet 1998 Aug 1
bullet 1998 Jul 15
bullet 1998 Jul 1
bullet 1998 Jun 15
bullet 1998 Jun 1
bullet 1998 May 15
bullet 1998 May 1
bullet 1998 Apr 15
bullet 1998 Apr 1
bullet 1998 Mar 15
bullet 1998 Mar 1
bullet 1998 Feb 15
bullet 1998 Feb 1
bullet 1998 Jan 15
bullet 1998 Jan 1

Orbital elements for 1997

bullet 1997 Dec 15
bullet 1997 Dec 2
bullet 1997 Nov 15
bullet 1997 Nov 1
bullet 1997 Oct 16
bullet 1997 Oct 1
bullet 1997 Sep 17
bullet 1997 Sep 1
bullet 1997 Aug 16
bullet 1997 Aug 5
bullet 1997 Jul 15
bullet 1997 Jun 29
bullet 1997 Jun 15
bullet 1997 May 31
bullet 1997 May 13

Last Modified May 7, 2008