Looking for Charles’ Heart
You’ll have to explore Canes Venatici
As evening twilight gives way to darkness, the first star to appear is likely no star at all but rather Venus, so bright you may be able to spot it in the west-northwest before sunset. By the time the sun does set, there should be no mistaking Venus, although the evening star does have company.
While last week Mercury and Jupiter pirouetted in tight formation around Venus at sunset, the three are equally spaced in a line through this weekend. Mercury is roughly four degrees above Venus, while Jupiter is the same distance below the evening star. At their closest, the three planets are within seven degrees of one another, but the line stretches each night as Jupiter sinks lower and Mercury climbs higher, reaching its zenith June 7. This is the innermost planet’s best evening apparition of the year. But even as Mercury climbs higher, it dims night by night, so spot it while you can in the hour following sunset.
The remaining visible planet stays up all night. Saturn appears in the southeast at twilight and by 11:30pm is at its highest due south. It sets after 3am.
One of the most recognizable figures in the heavens, the Big Dipper shines high overhead through the night. Yet the Big Dipper is not itself a constellation, but rather part of Ursa Major, which has been seen as a great she-bear throughout the ages, from Babylonia to India, North America to Greece.
Trailing the ancient and familiar bear is one of the more modern and least-recognized constellations: Canes Venatici, the hunting dogs. Not to be confused with Canis Major and Canis Minor to the south, these are the hounds of Boötes the bear-herder, created in the 17th century by Polish astronomer Johannes Hevelius. None of the stars are standouts, the brightest being Cor Caroli, or Charles’ heart. Typically magnitude 2.8, it is a variable double star, and legend has it that it shone particularly bright at the execution of England’s king Charles I.