18 - Nova? What nova?

Summary

The afternoon summer storm has just passed and the sky is clearing rapidly. It's a weekend evening and you decide to set up the telescope. By the time the Sun has set, your telescope is assembled and you are ready for a night with the stars. What do you do first? While the telescope is adjusting to nighttime temperatures, check out the sky. Is it just as you left it last time? A good way to begin any night of observing is to review the familiar constellations and asterisms. Slowly and methodically check each star down to 2nd or 3rd magnitude. In all likelihood, all is well, but you never know. An erupting star, a nova, might be out there waiting to be noticed as a “star out of place.” A nova is not, as its Latin name implies, a new star. It is really an old star system that is exploding. In the case of an ordinary nova it is a binary system that goes into outburst as it blows off some of its atmosphere, or as a supernova, it spectacularly blows a large fraction of its mass over space.

A nova in Cygnus

On a Saturday evening in late August 1975, when I was returning with friends from an early dinner, I looked up, quite by habit, and saw what I assumed to be a slow-moving satellite just north of Deneb.