June 30, 2023: Venus’ chase of Mars ends this evening with a quasi-conjunction. The bright evening gibbous is near Antares.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 5:19 a.m. CDT; Sunset, 8:30 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.
The month and the calendar quarter end with fifteen hours, eleven minutes of daylight at Chicago’s latitude.
The sunset time is still at the latest time of the year.
Venus’ chase of Mars ends this evening with a quasi-conjunction. During the winter and spring months, Venus closed a gap in the sky to Mars. This evening’s closest spacing is 3.6°, a near or quasi-conjunction.
A conjunction would occur if Venus passed Mars. Since they do not share the same celestial longitude, but appear within 5.0°, this is known as a quasi-conjunction. In his book Astronomical Tables of the Sun, Moon, and Planets, Jean Meeus lists twenty-three quasi-conjunctions of the planets from 2011 through 2040, nineteen are with Mercury. One occurs with Mars on August 13th. The gap is 4.7°. Three nights later, Venus has a quasi-conjunction with Regulus. The brilliant planet eventually passes Leo’s brightest star in October when they appear in the morning sky.
Venus appears to be approaching Mars in the sky, but in space they are nearly 160 million miles apart. Venus, on an inside orbital path, is overtaking our planet. This evening the distance is about 46 million miles. Earth continues to pull away from Mars, on an outside and slower orbital path. Tonight, it is over 205 million miles away, and appearing dimmer than when it was closest on November 30, 2022.
Summaries of Current Sky Events
Here is today’s planet forecast:
Morning Sky
Bright Jupiter is in the eastern sky with stars Capella and Aldebaran. The planet is nearly 30° up in the east at one hour before daybreak. It is slowly moving eastward in front of Aries, 11.1° to the lower right of Hamal, the constellation’s brightest star.
Capella, Auriga’s brightest star, is over 15° above the northeast horizon. It is the fourth brightest star visible from mid-northern latitudes, after Sirius, Arcturus, and Vega.
To the unassisted eye, Jupiter looks like a bright star. The word “planet” is from the Greek planete (πλανήτης) meaning wanderer or wandering star. The five bright planets – Mercury, Venus, Mars, Jupiter, and Saturn – are seen without an optical assist and they move relative to the “fixed” stars of the constellations. Add in the sun and moon and seven celestial objects have the power to move compared to the starry background, although the sun’s motion through the stars reflects Earth’s revolution.
The planets do not appear in the brightest stars list. While they resemble bright stars in the sky, they are worlds that revolve around the central star and they shine from reflected sunlight, while the stars are distant suns that make their own light.
Through a binocular up to four of Jupiter’s largest moons are visible. At 5:15 a.m. CDT, the planet’s Great Red Spot is visible at the planet’s center in the southern hemisphere through a telescope. This occurs a few minutes before sunrise in Chicago, but the spot can be seen earlier during twilight. The scene occurs in a darker sky for North American sky watchers farther westward from Chicago.
Look for the Pleiades star cluster, less than 20° up in the east-northeast, and below a line from Capella to Jupiter. Aldebaran is below the stellar bundle and near the horizon.
Saturn, dimmer than Capella, is nearly 40° above the south-southeast horizon. The Ringed Wonder is retrograding – an illusion that the planet is backing up compared to the starfield – in front of Aries.
The star Fomalhaut, meaning “the mouth of the southern fish,” is about halfway from the horizon to Saturn.
Frequent readers and podcast listeners recall that Saturn was approaching Deneb Algedi – meaning “the kid’s tail” – from the west as the planet disappeared behind the sun earlier during the year. When Saturn reappeared in the eastern sky it was east of the star. This morning the separation is 13.2°.
After midnight tomorrow, Mercury is at its solar conjunction. Technically, it is still in the morning sky today, but it rises only eight minutes before the sun.
Evening Sky
The Venus-Mars quasi-conjunction occurs this evening as described earlier. Brilliant Venus is “that bright star” in the west after nightfall. One hour later, the planet is less than 15° above the west horizon. The planet is setting earlier compared to the sun, losing three to four minutes of setting time each evening.
Along with Venus, Mars is in front of Leo. The Red Planet is 3.6° to the upper left of Venus and 5.9° to the lower right of Regulus.
Watch the planets appear to converge on Regulus. Mars passes the star on July 10th. Venus does not reach Regulus, but a quasi-conjunction occurs six nights later.
The three objects are gathered closest on the night of July 9th, when they appear in a circle that is 4.7° in diameter. This is easily visible through a binocular. Scout out a clear western horizon to spot this gathering.
This evening the gibbous moon, 92% illuminated, is low in the south-southeast, 3.1° to the upper right of Antares, the Scorpion’s brightest star. A binocular is needed to trace the head and body of the celestial arachnid. The tail curves below the horizon, reappears, and ends with Lesath and Shaula, the tip of the tail and stinger, sometimes named the Cat’s Eyes.
The moon is at the Full (Buck) moon phase at 6:39 a.m. CDT on July 3rd. Continue to watch the celestial dance in the western sky with Venus, Mars and Regulus
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