: By Francine JacksonMany of you are familiar with Dava Sobel's previous books, especially Longitude and Galileo's Daughter, both of which required extensive historical research. This one introduces a part of history that many astronomers use every day, but perhaps aren't aware from where it came: Spectral classification.
: By Dave HuestisThere is a lunar phase which is not observed as regularly as those phases leading up to and just after full. Today’s column will highlight a few of the features that can be observed during the Last (or Third) Quarter Moon. Binoculars or a telescope will be required to adequately observe these formations.