November 30, 2009: The Eclipse of Algol

Dave Goggin

Last night I finally got to see Algol go from its full brightness to its dim eclipsed state. As usual for such things I checked it every hour from my home in downtown San Francisco.

Started looking around 6pm before the eclipse started. By 7pm the eclipse was underway but I couldn't really notice a difference. Of course the moon was very annoying nearby. By 8pm Algol was looking slightly dimmer than it's comparison star Almach although I was still pretty unimpressed at that point.

Things got going by 9pm, by which time Algol was definitely the dimmest of its L-shaped asterism (Almach-Algol-Mirfak). By 10pm, it was even fainter, quite difficult to see with unaided eye (city light pollution and bright moon nearby didn't help), and thru the 8x21 binoculars it was dim enough to start to be considered 'in the same league' as rho Per nearby.

Mid-eclipse was around 11pm. By then Algol was mostly invisible to the unaided eye, very faintly visible only occasionally. Thru the binoculars just a bit brighter than rho Per which it normally seriously outshines.

Afterward I figured I'd seen enough and went to bed rather than also watching the diseclipsement.

Special thanks again to calsky.com for the accurate eclipse schedule.

Tonight: HU Tauri (maybe, weather permitting)