Autumn sky map algol7/28/2023 When an asterisk (*) is used, it means that the eclipse will occur not on the date listed, but on the previous calendar day. Daylight Saving Time has been accounted for in March. The table associated with this guide gives the dates and local times for the next four eclipses that can be observed from parts of North America in February and March. The star spends the rest of the night, slowly descending down into the northwest sky, and will be quite low to the northeast horizon by around 1 a.m. How to see Algol's winking natureĭuring the next month, Algol can be found about one-half to two-thirds up in the western sky as darkness falls. The whole complex system is a source of radio and X-ray emission. ![]() Algol C is a white star that is four times as bright as the sun. Yet another star, Algol C, circles the A and B pair from once every 1.86 years. Algol B is a yellow star that is "dim" when compared to the brighter blue star, yet compared to our sun it is three times more luminous.Īlgol A and Algol B are both several times larger than the sun. The dimmer star Algol B is the eclipsing body. The brighter star, Algol A is a bluish star about 90 times more luminous than our sun. The star is located about 90 light-years from Earth, and is actually made up of two stars in a binary system. Amazingly, he also correctly suggested the reason for the brightness variations: A large, dim body orbits the star and periodically blocks much of its light from our view. He observed the star systematically and determined its period. Īlgol's variability was rediscovered in 1782 by the English amateur astronomer John Goodricke, an 18-year-old deaf mute. Perhaps this is why few other astronomers paid much attention to Montanari's discovery at the time. At that time the only other variable star known (save for a few novae) was Mira, whose light varies over months instead of hours. The first person who definitely noticed Algol's winking behavior was the Italian professor of mathematics Geminiano Montanari of Bologna around the year 1667. So the eye of Medusa seems to "wink" at nearly three day intervals. While diminished light lasts nearly 10 hours, the eclipse begins and ends so gradually that most of the fading and subsequent brightening takes place within the two hours before and two hours after mid-eclipse. Normally, Algol appears 3.3 times brighter than during the peak of the eclipse it usually shines at magnitude 2.1, about equal to the nearby star Almach in the constellation Andromeda, but when it's at minimum light, it fades to about magnitude 3.3, or about equal to the brightest star in another nearby star pattern, Triangulum. The literal translation of Algol means, "The Mischievous One." Yet if the dimming of Algol was noticed by the ancient watchers of the night sky, the records say nothing about it. ![]() On the other hand, a 2013 paper published in the Astrophysical Journal by a team of researchers, suggests that a calendar for lucky and unlucky days composed in Egypt some 3,200 years ago, shows a distinct periodicity of 2.85 days and several empirical tests indicate that this periodicity just might be connected to Algol. It is due merely to Algol's position marking the severed head of the Gorgon Medusa in ancient Greek constellation mythology. The name Algol comes from the Arabic al-ghul, the female demon, but contrary to many popular accounts, the name apparently has nothing to do with the star's behavior. ![]() The lower arm of the K points at the Pleiades star cluster, but it upper arm ends at the star Algol, which has a long and venerable history. Located near the W-shape of the constellation Cassiopeia is the constellation Perseus, which resembles a lopsided letter K in the sky. To find Algol in the night sky, you should look well up in the western sky at nightfall. Because the entire eclipse takes 9 hours and 40 minutes from start to finish, the entire performance can be seen in a single night when the timing is right. This variable star eclipse occurs like clockwork at intervals of 68 hours, 48 minutes and 59.9 seconds, or 2.86736 days. The so-called "demon star" of Algol is the most prominent eclipsing variable star in the night sky, and if you know when and where to look, you can see the star appear to wink as it is eclipsed by another, dimmer star.
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