Comet charts

The charts below show positions calculated for 0h UT on the indicated dates from the latest osculating elements given in the Minor Planet Centre's database. Star data are from the Hipparcos/Tycho databases. The selection of comets is mainly derived from the summary on the web site of the BAA Comet Section.

The charts are interactive to assist with magnitude estimation. There is further explanation at the bottom of this page.

next to a chart provides a link to a red-on-black version, for display while observing.
Messier and NGC objects are marked on the charts by small squares.
The time, T, of (the nearest) perihelion is given for each comet.

NEW 2014 Jan 26: Charts starting Feb 1 onwards have some new features:

A chart for any object at any one date & time can also be plotted from our "What's observable" applet, including comets not listed here.

Periodic comets, in numerical order
Other comets, in order of discovery
Interactive charts

As you move the mouse over a chart certain data for the nearest star are displayed below it:

The id is given so that further information can be found elsewhere if desired.

V magnitude is given to enable visual comet magnitude estimation using the defocussing technique (see J.Shanklin, BAA Observing Guide to Comets, 2002).

B - V is given so that stars with a similar colour index to the Sun can be used. Dust comets are reflecting sunlight so comparison magnitudes need to be for similar stars. The Sun's B - V value is reckoned to be 0.66 (see David F. Gray, The inferred colour index of the Sun, 1992).

The chart also displays green boxes around the most Sun-like stars: those in the range 0.60 < B - V < 0.72.

If your mouse is nearer to a 0h UT point along the comet's track than to a star you will see some ephemeris data in blue.

The interaction is done using standard HTML/JavaScript techniques that have been around for many years and so should work in all browsers. It has been tested in FireFox 20 and Internet Explorer 10. It is known to work in Android tablets. The code is generated automatically by our own chart generator using Hipparcos/Tycho data. Once you have the chart in your browser no further internet connection is needed for the interaction.

If you print the chart you will not get the star data. The idea is that you select the stars you want and make a separate note of their characteristics, perhaps written on the print. However, if you save the whole page from your browser you should be able to view it from disc with the full interaction.

The interactivity is not yet in the red-on-black versions of the charts but that will come soon.

Section Director
Sheridan Williams FRAS

Section Director, Sheridan Williams

Contact Sheridan

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