These travelling masses of ice and dust galloping throughout the universe are believed to have shaped the course of life on this planet. As a result of comet-hunting, many deep-sky objects including nebulae and galaxies have been discovered with perhaps the most obvious collection being the 109 (or 110) DSO's attributed to Charles Messier. With over 1000 comets now having been catalogued and approximately 200 having been established as being periodic, historical records suggest comets to have been observed and documented as far back as 240 BC (Comet Halley by the Chinese).

Comets are appealing to amateurs for a variety of reasons: they lead to incredible photographs thanks to their glowing and colourful tails extending millions of kilometers as they approach the sun and the ice and various frozen gases in the nucleus begin to vaporize; they are the precursors of meteor showers as remnants left behind on prior visits are encountered by our planet while we orbit the sun; and they represent an active adventure and form the basis of a "culture" (comet hunters) based on the discovery of new comets during the early dawn hours on the eastern horizon or just after sunset on the western horizon.

Note: Comet C/2009 R1 (McNaught) illustrated below while passing through the constellation of Andromenda and within the immediate vicinity of the edge-on galaxy NGC 891 was discovered on Sept 9, 2009 by Siding Spring Observatory astronomer Robert McNaught in five plates and was estimated to be magnitude 17.3 to 17.5. Continuous monitoring has revealed a continuing brightening of the nucleus and which is now expected to reach mag 2 by the end of June and early parts of July when it will finally be lost in the morning twilight. Perihelion has been estimated to be July 2, 2010.

For an ephemeris and orbital elements on this hyperbolic comet from Harvard's Minor Planet Center, click here. For a simulation of the comet including various orbital elements and physical parameters, click here.

Note: The comet was only 12 to 19 degrees above the horizon during the imaging session!