September 24, 2021
The bright variable star Algol can be found in the northeast after 8:30 pm. Algol is the second brightest star in Perseus which appears as an upside-down Y-shape. If you watch Algol for several nights, you might notice the star dim from 2.1 to 3.4 magnitude. What you are seeing is two stars eclipsing one another which occurs every 2.87 days. The next good opportunity to see this is on October 3, 2021. Learn more about Algol at AAVSO and calculate its minima times at Sky and Telescope.
The constellations Perseus and Cassiopeia rising in the northeast at 8:30 pm. Image created using Stellarium.
