Auriga is the “Charioteer” in the sky, and is quite prominent in the sky now. Its brightest star is Capella. A fairly bright star (3rd magnitude) not far away from Capella called epsilon Aurigae is undergoing one of its unusual dimmings. These happen once every 27.1 years. It should reach its minimum light state around December 21st. If you look up at Auriga, you might notice that something looks “different” in the outline of that constellation.
Right now and over the next two years an effort is underway to understand one of the mysteries that have puzzled astronomers over the last 200 years. What is so unusual is that in mid-eclipse there is a slight, temporary recovery in brightness. The going theory is that the system is a binary system like many eclipsing variable stars, but a large gas cloud “donut” might also be involved.
There has been a “call” to amateurs and professionals alike to measure the brightness of this star and build a very large set of observations. A DSLR camera on a tripod is all you need to do some interesting work! Here are some links that explain how.
http://www.hposoft.com/Campaign09.html
http://www.hposoft.com/EAur09/EAUR%20pdfs/DSLR.pdf
From the pdf document: “Des Louhney has proven that DSLR V band photometry can result in measurements of epsilon Aurigae that are useful and significantly more accurate than visual estimates. An amateur astronomer, without a telescope or a drive can make accurate V band observations of epsilon Aurigae, before, during and after the current eclipse using just a color DSLR camera mounted on a fixed tripod.”
Encouraged by this, I have been giving this a try using my Canon EOS 450D DSLR on a tripod. With its 55mm lens, I can make exposures of 15 seconds with little star trailing. Using the MaxIm DL5 software, I have started making regular estimates of eps Aurigae’s brightness. In the pix below, it was at about magnitude 3.5.
It has been fun too to “see the stars again” using the camera and software. My home is in a fairly light polluted part of Pewaukee. I am amazed to see stars as faint as the ones that show up in these images.
Clear Skies!
