This week's Light Curve of the Week is less about the star -- the eclipsing binary Z Draconis -- than it is about this particular observer, Ed Halbach. Halbach was one of the most prolific of the AAVSO's 20th Century observers, sending us regular observations of hundreds of stars from 1934 up until the first decade of the new millenium. Overall, he submitted just over 100,000 visual observations to the AAVSO, one of only a handful of observers that achieved that feat. Ed Halbach passed away just two weeks short of his 102nd birthday on March 20, 2011.
Z Draconis is an eclipsing binary of the Algol type with a period of around 1.35 days. This light curve shows an example of one eclipse observed visually, as visual observers do during their eclipse timing observations. Most published EB minima are derived from instrumental data now, but visual data such as those by Halbach provide a strong historical record of the past behavior of eclipsing binaries.