An Unfavourable Star

by Jason Hatton


I enjoyed Jay's essay on the risks and potential consequences of a near earth asteroid impact.

Interesting 2002 NY 40 is the third NEO in the last 15 months to be easily visible in a small scope (4" or smaller). 1999 KW4 was visible in late May 2001 at around mag +11 for several days approaching earth within 4.8 million km on May 25 2001. On December 15-16th 2001 the 1km sized asteroid 1998 WT24 approached within 2 million km of earth. That evening the weather in San Francisco co-operated and I observed 1998 WT24 slowly, but perceptibly, moving amongst the stars as a 10th magnitude point of light.

To observe 2002 NY 40 I eventually drove up to Lake Sonoma on Saturday, hoping that I was far enough from the coast to avoid the fog. Although the fog did eventually arrive around 22:30 I did manage to get a half an hour of good observations with my G9.25, along with two other observers who were also at the site. As others have pointed out the asteroids motion was readily perceptable, requiring a reasonable amount of panning of the telescope drive to keep up with it.

Having three NEO's visible in back yard scopes in the last year may be good luck, but also the NEO search programs are turning up more of these objects that would have previously gone undetected. The next one (that we know of) that will be easily visible will be 4179 Toutatis in 2004, which should be as bright as 9th magnitude. However, as Jay pointed out being able to detect an asteroid on a collision course with earth isn't going to help us unless we have some means of deflecting it.