Reporting and Validating a Nearby Supernova
Four observatories detect incoming neutrinos; a SuperNova Early Warning System (SNEWS) alert goes out, bouncing off AstroAlert and into your computer, handheld PDA, or mobile phone. You're told that the best place to look is at right ascension x, declination y, and that the "error box" is 5° by 10°.
You grab a star atlas and spin a planisphere to see how soon you'll have an opportunity to search.
If you're lucky, a half day after you receive the alert, evening twilight will begin to dim and the target area will already be high in the east a whole night's searching awaits! (If you're very lucky, everyone else in the world will be clouded out or having lunch!) You fit a CCD to an 85-mm camera lens and paint the target region with six images exposed a minute each. Then you check the field against your favorite star atlas or charting software. "Hey!" you say, "What's that 9th-magnitude star where no star ought to be?"
A minute later, Sky & Telescope receives your report and image. Staffers at S&T and the American Association of Variable Star Observers (AAVSO) immediately check that the putative new star lies within the error box and that no known star or asteroid matches its position. (Rigorous checking must be done because every minute of world-class-telescope time is precious and expensive!)
Since the perfect world doesn't exist, the first observation of a putative supernova will likely pinpoint a star fainter perhaps much fainter than magnitude 10.0, the limit at which our knowledge of star positions and brightnesses is essentially complete. (In fact, it's possible that the supernova responsible for the neutrino signal will be so deeply buried by an interstellar cloud that its light never emerges.) The second imperfection is that the error box could be a lot bigger than 50 square degrees like 400 times bigger, encompassing an entire hemisphere!
For faint suspects, the confirmation process rapidly becomes more complex and much less certain. A spectrum might be essential, for a supernova's anticipated brightening rate can be mimicked by ordinary novae and other variable stars. (Maurice Gavin describes his wonderfully efficient and easily made spectrograph in "The Revival of Amateur Spectroscopy". Accompanying his article is "A Field Guide to Supernova Spectra", showing how they might be recorded by amateurs.)
Of course, work with small telescopes shouldn't end with the confirmation of the supernova. S&T and the AAVSO will act as a clearing-house for observations through at least the early phase of the supernova's rise. Our aim is to produce the most accurate light curve possible. As we do so, we'll happily collect other observations of relevance to the scientific community.