May 7, 2024: Shining from the eastern sky before sunrise, Mars and Saturn are morning planets. Look for stars Arcturus and Spica after sundown.
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by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 5:39 a.m. CDT; Sunset, 7:56 p.m. CDT. Check local sources for sunrise and sunset times. Times are calculated by the US Naval Observatory’s MICA computer program.
Daylight and Twilight Increase
As spring progresses, daylight increases. The more northerly sun makes a longer arc across the sky. At the same time, the sky stays brighter longer during the evening and morning twilight begins earlier compared to sunrise. With twilight lasting nearly two hours before sunrise, then again after sunset, observing times in these articles shift to one hour before sunrise and the same interval after sunset. This is about the middle of twilight and is applied to these articles during late spring and early summer.
While Chicago’s sunrise and sunset times are listed here, find local times for these events and add or subtract the appropriate time interval.
Summaries of Current Sky Events
Summary for Venus as a Morning Star, 2023-24
Here is today’s planet forecast:
Morning Sky
Mars and Saturn are Morning Planets
Mars and Saturn are in the eastern sky before sunrise. They are the only bright solar system bodies visible during nighttime hours.
At one hour before daybreak, yellow-orange Saturn is over 10° above the east-southeast horizon. The planet slowly moves eastward against the dim starfield that is awash in morning light, although not as quickly as Mars.
The Red Planet passed the Ringed Wonder on April 10th and has opened a wide gap. This morning Mars is over 5° above the east horizon and 18.0° to Saturn’s lower left. While reddish Mars is marginally brighter than Saturn, a binocular is likely needed to see it. The planet’s color mixes with the hues of approaching sunrise.
Mercury and Venus
Venus is at solar conjunction early next month. Lost in bright twilight this morning, it rises about 15 minutes before the sun.
Appearing at its largest separation from the sun in two mornings, the planet rises over 50 minutes before daybreak. It is very difficult to locate 3.5° above the east horizon at 30 minutes before sunrise. For practical sky watching, Mercury is not visible. Mercury aficionados should find a clear eastern horizon and take along some extra patience.
Evening Sky
New Moon
The moon is at the New phase beginning lunation 1254, the number of lunar cycles since the counting system started in 1923, at 10:22 p.m. The lunar crescent returns to the evening sky in two evenings.
Jupiter
Jupiter sets during bright evening twilight, reaching its solar conjunction on the 18th. It reappears in the eastern morning sky next month.
With winter’s bright stars disappearing into western evening twilight, a few bright stars are in the eastern sky.
Bright Arcturus is about halfway up in the east-southeast. The star is 37 light years away and shines with the brightness of 100 suns.
Arcturus and Spica
Topaz Arcturus is the brightest star in the northern half of the sky and the second brightest star, after Sirius, for northern hemisphere sky watchers. The celestial equator, an imaginary circle above Earth’s equator, divides northern stars from those on the southern half of the celestial sphere.
The star’s name means “bear guard” and along with its constellation, Boötes, they chase the Great Bear (Big Dipper).
In Chicago, Arcturus has connections to great events in the city. The 1933 World’s Fair used Arcturus’ light to energize photoelectric cells attached at the eyepieces of four telescopes in the eastern U.S. – Yerkes Observatory, University of Illinois, Allegheny Observatory, and Harvard Observatory – to switch on a searchlight that signaled the beginning of the fair.
Arcturus was thought to be 40 light years away. The 1933 fair was 40 years after the 1893 Columbian Exposition that also occurred in Chicago.
In contrast, sapphire Spica is about one-third of the way up in the sky above the southeast horizon. South of the celestial equator, it is the 10th brightest star for sky watchers at the mid-northern latitudes. The star is 250 light years away, shining with a brightness of nearly 2,000 suns.
Spica means “ear of corn,” and sometimes interpreted as an ear of wheat. Virgo is associated with agriculture representing Ceres daughter or with justice as the daughter of Zeus and Themis.
Use a binocular to compare the colors of the two stars. Arcturus’ topaz represents stars that are not as hot as our sun and bluish Spica is considerably hotter.
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