2023, May 18: Capella’s Heliacal Rising, Celestial Snake


May 18: The bright star Capella makes its first morning appearance, known as the heliacal rising. Look for Hydra’s dim stars during the night.

August 4, 2018: Venus from the Arizona desert.


by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 5:28 a.m. CDT; Sunset, 8:07 p.m. CDT.  Check local sources for sunrise and sunset times for your location.  Times are calculated by the U.S. Naval Observatory’s MICA computer program.

Here is today’s planet forecast:

Morning Sky

Summaries of Current Sky Events


This morning, the star Capella is making its first morning appearance, known as the heliacal rising.  A star’s first appearance can be theoretically calculated, but the actual date is subject to weather, local terrain, and nearby obstructions. Find it about 5° above the north-northeast horizon.

Capella is in the evening sky in the west after sundown to the right of Gemini and Venus.  It is the fourth brightest star, after Sirius, Arcturus, and Vega, visible from the mid-northern latitudes.  It is nearly 150 times brighter than the sun and it shines from over 40 light years.

Capella, like Arcturus and Vega, can be seen both in the evening sky and before sunrise.  They are farther north in the sky than the sun, so for Capella it sets after the sun and rises before it during this season.

Chart Caption – 2023, May 18: Jupiter, Saturn, and Fomalhaut are in the eastern sky before daybreak.

Jupiter and Saturn are visible before sunrise as well.  Bright Jupiter is low in the eastern sky.  It is emerging from bright sunlight.

Saturn, dimmer than Jupiter, is nearly 25° above the southeast horizon.

Look for Fomalhaut, making its first morning appearance for many sky watchers, 5.0° above the horizon.

Mercury is another celestial wonder emerging from bright sunlight.  Rising only twenty-five minutes after Jupiter, the speedy planet is only 6° to the lower left of Jupiter, but it is lost in the light of sunrise.  It has an unfavorable appearance next month.

Evening Sky

Chart Caption – Venus moves in front of Gemini, May 7-June 2, 2023.

Brilliant Venus is “that bright star” in the west after nightfall.  At forty-five minutes after sunset, the planet is one-third of the way up in the sky from the horizon to overhead, corresponding to 30° altitude.  The Evening star is stepping eastward in front of Gemini, 2.2° to the upper left of Mebsuta and over 10° below Castor, one of the Twins.

Chart Caption – 2023, May 18: Brilliant Venus and Mars are in the western sky after sundown.

Mars, marching eastward in front of dim Cancer, is less than 17° to the upper left of Venus and 7.5° to the left of Pollux, the second Twin.  The planet is dimmer, now about the brightness of Pollux.  It may even look dimmer than the star. To some sky watchers, reddish “stars” appear dimmer than blue stars of equal brightness.

Gemini is one of a few constellations that resembles its namesake. When the sky is darker, the dimmer stars are visible and the pattern makes two side-by-side stick figures.  The brightest stars, Castor and Pollux, dot the Twins’ heads.

As Capella makes its first morning appearance, it is in the northwestern sky, to the right of Venus and Gemini this evening. The star is part of a pentagon-shape known as Auriga, the Charioteer.

Chart Caption – May 18: Hydra the Snake crosses the sky on spring evenings.

With this darker sky and until the moon reappears and brightens in a few evenings.  Look for the constellation Hydra – the Snake.  The constellation stretches across the sky from Procyon to past Spica.  Its head is less than halfway from Procyon to Regulus, that is about halfway up in the sky in the southwest. The brightest star, Alphard – meaning “the Solitary One” – is about halfway from the horizon to Regulus. The body zigzags across the sky under Crater and Corvus, ending near the Scorpion’s claws.  It stretches nearly one-fourth of the way around the entire sky!

In one myth, Apollo sent a raven (Corvus) to fetch some water in a cup (Crater) from a fountain.  On the way the bird stopped to eat figs and was late returning to Apollo with the water.  On the way Corvus saw a snake and caught the serpent in its claws.  On return the bird accused the snake of attacking and delaying the flight back.  Apollo recognized the lie and placed the trio into the sky.  The celestial snake keeps the bird from drinking from the cup.



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