March 21, 2023: Delphinus and Sagitta are in the eastern sky before sunrise. Jupiter, Venus, and Mars are easily visible in the western sky after sundown.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:53 a.m. CDT; Sunset, 7:04 p.m. CDT. Check local sources for sunrise and sunset times for your location. Times are calculated from the U.S. Naval Observatory’s MICA computer program.
The New moon occurs today at 12:23 p.m. CDT. A very thin moon is near Jupiter tomorrow evening. Lunation 1240, the number of lunar cycles since 1923, begins at this phase.
Here is today’s planet forecast:
Morning Sky
An hour before sunrise, the Summer Triangle is in the eastern sky. Altair, meaning “the flying eagle,” is the southern vertex of the triangle. It is the brightest star in Aquila, the Eagle. The constellation somewhat represents a flying bird. Three stars line up in a row and might be mistaken for Orion’s belt except for the presence of brighter Altair as the middle star. Two triangles extend up and down indicating the wings and then a westward extension of stars for the tail.
Altair is the eighth brightest star visible from the mid-northern latitudes. At a distance of nearly 17 light years, it shines with a brightness of over 11 suns.
Notice on the accompanying chart Albireo, the nose of Cygnus, a double star that is a great contrast of star colors in a telescope – golden and sapphire.
In this region of the sky are two smaller constellations, Delphinus and Sagitta. Delphinus is to the lower left of Altair. A diamond shape makes the body of a dolphin and a star nearby indicates the tail. The dolphin is curved as if it were airborne.
Sagitta, the Arrow, is to the upper left of Altair. The arrow’s point is to the left and the fletching is to the right.
Both constellations are dim and each easily fits into a binocular’s field of view.
Delphinus is recognized in mythology when a dolphin rescued harpist Arion from a mutiny on a hired vessel that was to carry him from Sicily to Corinth.
Sagitta could be part of the aftermath from Hercules sixth Labor of removing the Stymphalian birds, an avian species that had iron wings and fed on humans. In one version of the myth, he hunted them with a bow and arrows. Aquila could be a representation of the birds and Sagitta an arrow from the quest.
Saturn continues to climb into the morning sky. Not yet in a place for easy observation, the Ringed Wonder is nearly 5° up in the east-southeast at 30 minutes before sunup.
Evening Sky
Mercury continues to race into the evening sky after its recent superior conjunction. It sets twenty minutes after the sun. Each evening it sets five to six minutes later. Like Saturn, it is not ready for easy viewing.
By forty-five minutes after sundown, brilliant Venus is visible about 25° above the western horizon. It is the brightest starlike body in the night sky. Notice that it is lower than Sirius, the night’s brightest star about one-third of the way up in the south. There is a qualification between the words “starlike” and “star.” The five brightest planets – Mercury, Venus, Mars, Jupiter, and Saturn – look like stars to the unassisted human eye, but they are worlds that shine from reflected sunlight. A star makes its own light, like the sun, but they are much farther away and appear too dim to make daylight on Earth.
Jupiter, over 5° above the western horizon, is 19.5° to the lower left of Venus. Find a clear western horizon to see the two planets. The Jovian Giant is slowly slipping into brighter twilight, while Venus steps eastward about 1° each evening and sets nearly three hours after sundown.
Venus is approaching a wide conjunction with the star Hamal, the brightest star in Aries, in two evenings. This evening Venus is 9.7° to the lower left of the star.
Venus is closing a very wide gap to Mars that is high in the southwest as the sky darkens. This evening the separation is over 52°. Each clear evening, notice how the gap between the two planets closes.
The Red Planet is east of Taurus’ horns, Elnath and Zeta Tauri, and approaching the Gemini border. It is 6.3° to the upper left of Elnath, the northern horn, 5.4° to the upper right of Zeta, the southern horn, and 6.2° to the lower right of Propus, Castor’s toe.
Mars is dimming since Earth was closest on November 30, 2022. As the separation increased, the planet dimmed in our sky. This evening it is dimmer than Capella, to its upper right and nearly the same brightness as Aldebaran, Taurus’ brightest star, to its lower right. Betelgeuse is not a reliable reference because its brightness noticeably changes. A Twitter account, @betelbot, tracks the reports of the star’s brightness each night.
Through a binocular, Mars and Propus appear with a star cluster cataloged as Messier 35 (M 35 on the chart). The stellar bundle has bluish stars similar to the Pleiades star cluster, but M 35 is nearly five times farther away. As the waxing moon moves into the sky, the brightening moonlight whitewashes dimmer celestial wonders. Look for the cluster through a binocular during the next few evenings.
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