June 19, 2023: Morning planet Saturn retrogrades against Aquarius. The thin crescent moon is below the Gemini Twins during evening twilight.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 5:15 a.m. CDT; Sunset, 8:29 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.
For the second day, daylight lasts fifteen hours, fourteen minutes, the longest daylight period in Chicago. The lengths of twilight and darkness are nearly equal to complete the twenty-four-hour period.
Summaries of Current Sky Events
Here is today’s planet forecast:
Morning Sky
Two bright planets, Jupiter and Saturn, are in the morning sky. Saturn is about 30° up in the south-southeast at one hour before daybreak. The planet is slowly retrograding. Saturn appears to move westward against the background stars. This is an illusion from Earth beginning to move between the Ringed Wonder and the sun.
On the accompanying chart notice the three positions labelled with letters A, B, and C. A is Earth’s position when Saturn appears to retrograde. The red arrow is the line of sight from Earth to Saturn toward the background stars. At location B, Earth is between Saturn and the sun, known as opposition. From location A to location B, the line of sight shifted westward or backwards from Saturn’s normal direction. The same occurs from location B to location C, when retrograde ends. During the four and one-half month period, both planets revolve around the sun, but Saturn appears to go backwards against the stars. After location C, Saturn appears to move eastward again.
Aquarius is a dim constellation and washed out by the outdoor lighting in urban and suburban settings. A few stars are as bright as those in the Big Dipper, but the dimmer stars are hiding in the glow of light pollution and morning twilight.
Fomalhaut, meaning “the mouth of the southern fish,” is about halfway from the horizon to Saturn. This star is the thirteenth brightest seen from the mid-northern latitudes. The star is twenty-five light years from the solar system and shines with a brightness of about 20 suns.
Bright Jupiter, about 20° up in the east, is moving slowly eastward in front of Aries, over 11° to the lower right of the constellation’s brightest star, Hamal.
Can you see the Pleiades star cluster low in the east-northeast? Use a binocular to initially see the stellar bundle.
Mercury continues to retreat into bright sunlight. This morning, rising forty-nine minutes before sunrise, the speedy planet is in very bright morning light when it is high enough above the horizon to be seen.
Evening Sky
The crescent moon, 4% illuminated, returns to the evening sky. It is less than 10° up in the west-northwest at forty-five minutes after night fall. It is 4.6° to the lower right of Pollux and 5.9° to the lower left of Castor, the Gemini Twins. At this level of twilight, a binocular is helpful to find the lunar crescent and the two stars.
Brilliant Venus continues to sparkle in the evening after sundown. It is overtaking our planet in the solar system and approaching Mars in the sky. On the accompanying chart notice the proximity of Venus to Earth and the larger distance from Mars to Earth.
When looking for the moon, Venus is about 20° up in the west, with the Red Planet 4.9° to the upper left of the Evening Star. Can you see Regulus, over 17° to the upper left of Venus? In two evenings, the crescent moon and Venus make a spectacular scene in the western sky.
This evening, Venus and Mars are in the same binocular field of view. After seeing them together, move the binocular so that Venus is toward the upper left portion of the field of view. The Beehive star cluster is to the lower right. In two evenings, Venus, moon and star cluster may fit into the same field of view, depending on the binocular’s capabilities.
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