For me, the greatest excitement of astronomy comes from the discovery of a new phenomenon or strange celestial object that nobody has ever seen before. Below are a few of the effects, interesting stars, and other discoveries that I have stumbled upon during my more than 3 decades of astronomical research.
The "Bond-Neff" Effect
In my first paper published in the Astrophysical Journal (ApJ,158, 1235, 1969), John Neff and I showed that barium stars have a deep, broad minimum in their flux distributions near 4000 A. More than three decades later, I am not sure the effect has yet been explained convincingly. Its presence is strongly correlated with an excess carbon abundance in the photosphere, suggesting that its carrier may be a carbon-bearing molecule; however, it could alternatively arise from numerous weak lines of s-process elements.
Bond's Flare Star in Pisces
While carrying out photographic objective-prism spectroscopy with the Curtis Schmidt telescope at Cerro Tololo in 1976, I serendipitously discovered what was at that time the largest stellar flare ever observed, when I happened to catch a previously unknown star in Pisces that rose some 8 magnitudes in about 15 seconds. Details were published in IAU Inf. Bull. on Var. Stars No. 1160. The star is now named "Bond's Flare Star" or AF Psc, and its spectrum was subsequently analyzed by Jesse Greenstein. A parallax measurement at the USNO showed it to be only 28 pc from the Earth.
The Optical Counterpart of GRB 970508
In May 1997 I had the thrill of identifying the optical counterpart ("Bond's Variable Object") of a gamma-ray burst, which proved to be the first one for which a redshift could be measured. This result finally settled the decades-long controversy over the question of the distance scale for GRB's, by decisively showing that they are at cosmological distances. The background image for this page shows the discovery frame, obtained with the Kitt Peak 0.9-m telescope on 1997 May 10. Read more about the story of this discovery here.