2024, July 21: Mars-Pleiades Conjunction

July 21, 2024: A Mars-Pleiades conjunction occurs this morning in the eastern sky during morning twilight.  Jupiter is to the lower left of Mars.

March 3, 2021: Mars appears to the lower left of the Pleiades.
March 3, 2021: Mars appears to the lower left of the Pleiades.

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by Jeffrey L. Hunt

Chicago, Illinois: Sunrise, 5:33 a.m. CDT; Sunset, 8:21 p.m. CDT.  Check local sources for sunrise and sunset times. Times are calculated by the US Naval Observatory’s MICA computer program.

Here is today’s planet forecast:

Morning Sky

Morning Buck Moon

2024, July 21: Two hours before sunrise, the Buck moon is in the southwest.
Chart Caption – 2024, July 21: Two hours before sunrise, the Buck moon is in the southwest.

Two hours before sunrise, the Buck moon is less than 15° up in the southwest.  Moon is opposite the sun, indicating the precise Full moon, at 5:17 a.m. CDT, shortly before sunrise and moonset in the eastern regions of the Central Time zone.  Locations farther westward see the moon higher in the sky.

The lunar orb is moving toward a conjunction with Saturn on the 24th. The moon occults or eclipses the planet for sky watchers in southeastern Asia. This morning the gap between them is over 50°.

Saturn

2024, July 21: An hour before daybreak, Saturn is in the southern sky.
Chart Caption – 2024, July 21: An hour before daybreak, Saturn is in the southern sky.

This morning at one hour before sunrise, the Ringed Wonder is less than halfway up in the southern sky.  It retrogrades in front of Aquarius, a dim starfield further affected by the bright moonlight and outdoor lighting.

Saturn retrogrades, 2024
Chart Caption – 2024: Saturn retrogrades through a single binocular field of view in front of Aquarius during 2024.

Use a binocular to track the planet’s slow progress against the background stars.

Jupiter and Mars

Mars-Pleaides conjunction
Chart Caption – 2024, July 21: During morning twilight, Jupiter and Mars are in the eastern sky.

Jupiter and Mars are in the eastern sky.  Less than a month before their conjunction, the Red Planet closes the gap to the Jovian Giant each morning.  The planet pair is in front of Taurus’ distant stars.  The vast starfield has many stellar landmarks to track the eastward planet positions.

An hour before sunrise, bright Jupiter – the brightest starlike body in this morning’s sky – is nearly 25° up in the east and 5.3° to Aldebaran’s upper left.  The planet is over 12° to the upper left of the Bull’s horns, Elnath and Zeta Tauri.

Mars-Pleiades Conjunction

Mars-Pleiades conjunction
Chart Caption – 2024, July 21: Through a binocular, Mars, Uranus and the Pleiades are in the same field of view.

A Mars-Pleiades conjunction occurs this morning. Mars, nearly 35° up in the east and 12.0° to Jupiter’s upper right, passes 4.8° to Alcyone’s lower right, the brightest member of the Pleiades star cluster. While the conjunction is wide, they easily fit into the same binocular field.

By moving the Pleiades to the upper left edge of the field of view, dim Uranus is in the right edge of the field.  It is to the upper right of 13 Tauri (13 Tau on the chart) and 14 Tauri (14 Tau). The planet is dimmer than 13 Tauri and brighter than 14 Tauri.

Reappearing Orion

Venus appears with Orion
2020, August 20: Venus shines with Orion and its bright stars Betelgeuse and Rigel.

Orion is beginning to climb across the eastern horizon during morning twilight.  Blue-white Bellatrix, one of the shoulders, is over 7° up in the east.  Betelgeuse, to Bellatrix’s lower left, is just above the horizon and might be visible through a binocular in a location with a natural horizon and no clouds. 

Betelgeuse’s first appearance or heliacal rising occurs in a few days. Begin looking for it on the 24th when it is 5° above the horizon.  Reddish stars tend to blend into the colorful hues of the predawn light and their first appearances occur when they are higher in the sky than bluer stars.

Evening Sky

Venus

Venus is slowly climbing into the evening sky.  Nearly 50 days since its superior conjunction, on the sun’s far side, the planet sets 45 minutes after the sun.  It is still in bright twilight. The planet is visible low in the western sky during bright twilight in about a week.

Mercury and Regulus

2024, July 21: At forty minutes after sundown, Mercury and Regulus are in the western sky. Use a binocular to see them.
Chart Caption – 2024, July 21: At forty minutes after sundown, Mercury and Regulus are in the western sky. Use a binocular to see them.

At 40 minutes after sundown and one day before its greatest elongation, speedy Mercury is about 5° up in the west and 3.7° to Regulus’ lower right, Leo’s brightest star.  Use a binocular to see them.

One way to look for a celestial body during bright twilight is to slowly move the binocular from side to side.  The sky’s brightness is constant, while the stars and planets move to reflect the binocular’s motion.

Nighttime Moon, Saturn

2024, July 21: Three hours after sundown, Saturn and the moon are in the southeastern sky.
Chart Caption – 2024, July 21: Three hours after sundown, Saturn and the moon are in the southeastern sky.

The moon rises less than an hour after nightfall.  Two hours later, it is nearly 20° up in the southeast and less than 40° to Saturn’s upper right. Tomorrow morning, find them in the southern sky.

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