Thursday, November 28, 2024

Medusa's Eye Pulses

The star Algol in the constellation of Perseus represents the glowing eye of Medusa from Greek mythology. Also designated Beta Persei, it is among the most accessible variable stars for skywatchers. During a ten-hour period that repeats like clockwork every 2 days, 20 hours, and 49 minutes, Algol dims noticeably and re-brightens by about a third when a fainter companion star
with an orbit nearly edge-on to Earth crosses in front of its much brighter primary, reducing the total light output we perceive. Algol normally shines at magnitude 2.1, similar to the nearby star Almach (aka Gamma Andromedae). But while fully dimmed, Algol's brightness of magnitude 3.4 is almost identical to Rho Persei (or Gorgonea Tertia or ? Per), the star sitting just two finger widths to Algol's lower right (or 2.25 degrees to the celestial south). On Thursday evening, November 28 at 6:03 p.m. EST or 23:03 UT, Algol will be at its minimum brightness. At that time it will be located one third of the way
up the east-northeastern sky. Five hours later the star will return to full intensity from a perch nearly overhead. Observers in more westerly time zones can see the latter stages of the brightening.

(Data courtesy of Starry Night)
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* Origin: CJ's Place, Orange City FL > cjsplace.thruhere.net (21:2/156)