What Comes Out at Night and Has Two Tails?

By Aaron B. Clevenson, ALCor

“Comets, importing change of times and states,
Brandish your crystal tresses in the sky.”
- William Shakespeare


This month, in the 18th article in our Astronomical League Club certification series, we visit some of the most fancy wanderers in the Universe, the Comets. Comets have been observed since prehistoric times, and their presence has been documented since 240 BC (Chinese records). In fact, as of 1995, there have been 878 comets identified. New ones are found all the time.

Comets are not simple bodies, like the asteroids, but have structure. There is a nucleus (ice, gas, dust and rocks), a coma (water, carbon dioxide, and other gases from the nucleus), a dust tail (up to 10 million km long and made up for tiny dust particles, this is what we usually see), and an ion tail (up to several million km long, made up of plasma). So, I guess the answer to the title’s question is… ta da… a comet!

The comet certification, a very new one, comes in two flavors: Silver (12 comets) and Gold (a total of 30 comets). Observations can be made visually (looking through the eyepiece and sketching) or images (with a CCD or camera). If it is a very faint comet, with no notable tail, then two observations are required to see it move.

That’s all there is to it. It sounds simple enough, but there are not many bright comets available at any given time, so it may take you a while to amass the required number of comets. Good luck.

Tune in next month for a look at the newest certification, one created by and coordinated by me, the Constellation Hunter Club.