Physics Photo of the Week

Warren Wilson College

January 10, 2005

Comet Macholz near the Pleiades. 

This winter (since mid December, 2004) a comet has been drifting across the sky.  I have been photographing this comet at almost every opportunity, which have been rare due to inclement weather.  The skies cleared Saturday, January 8 for this magnificent photo of the comet near the pleiades.  The image has been enhanced to accent the colors.  Notice that the stars in the Pleiades are mostly quite blue and the comet is rather "plain" or "greenish".  Some stars in teh field are red.  The Pleiades is a very young star cluster, and the stars are very massive (much more massive than the sun).  As a result the nuclear reactions in the surfaces of the Pleiades' stars are much hotter (about 10,000 K) whereas the sun is about 6000 K.  The comet (the fuzzy blob in upper right) is merely sunlight reflected by the dust of the comet.  The color of the comet dust cloud represents the color temperature of the sun which represents all colors, but more of the green than red and blue. 

The image on the right represents a cropped and enlarged portion of the original image, and more color enhancements.  Notice that the comet is definitely a "fuzz-ball" compared to the stellar images.  More information on comet Macholz may be found at the Sky and Telescope website:

The comet will be visible for about another month (until early February, 2005)

Photography details: The images posted here were photographed using an inexpensive digital camera (Canon A60) photographed through a makeshift telescope consisting of a 125 mm FL telephoto lens and a 40 mm FL eyepiece to give a magnification of 3.12.  The camera zoom lens looks through the telescope at 3X giving a total magnification of  about 9.4 - about what one sees through binoculars.  The makeshift telescope was mounted piggy-back onto a clock-drive telescope so that 20 images at 15 seconds each could be obtained and stacked to give the result shown here.  The main clock-drive telescope has too large a magnification to have photographed both the Pleiades and the comet.  A photo of the makeshift telescope and piggy-back mount is shown at right.

Physics Photo of the Week is published weekly during the academic year on Fridays by the Warren Wilson College Physics Department.  These photos feature an interesting phenomena in the world around us.  Students, faculty, and others are invited to submit digital (or film) photographs for publication and explanation.  Atmospheric phenomena are especially welcome.  Please send any photos to

Click here to see all Physics Photo of the Week for 2005

Click here to see all Physics Photo of the Week for 2004.