2021, April 5: AM Lineup, PM Mars

2021, April 5: The starfield with Jupiter and Saturn. Use a binocular to watch Jupiter and Saturn move eastward compared to the stars.

April 5, 2021:  The thick crescent moon, Saturn, and Jupiter are lined up in the southeastern sky this morning.  Mars is in Taurus after sunset.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 6:26 a.m. CDT; Sunset, 7:21 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

Morning Sky

This morning the thick lunar crescent is above the southeast horizon, near Saturn.  The Ringed Wonder is 13° to the left of the lunar slice. Bright Jupiter is nearly the same distance to the lower left of Saturn.

The chart for this morning includes several background stars.  During the next few weeks, daily notes will include detailed locations of Jupiter and Saturn compared to those stars.  If you live in a region without a proliferation of streetlights, you might be able to see the background stars without optical assistance.  For others use a binocular to track the planets.  This is a good observing project for students to note the direction and speed these two planets move.  The same occurs for Mars in the evening.

Here in the morning sky, Saturn is approaching Theta Capricorni (θ Cap on the chart).   Jupiter is in a region of three dimmer stars that help note the Jovian Giant’s changing locations.  The brightest is Deneb Algiedi (δ Cap), Mu Capricorni (μ Cap), and Iota Aquarii (ι Aqr).

Jupiter is nearing the Capricornus – Aquarius border.

This morning, Jupiter is 1.9° to the upper left of Deneb Algiedi, 2.0° to the upper right of μ Cap, and 5.1° to the upper right of ι Aqr. In a widefield binocular, Jupiter fits in the upper right of the field and ι is to the lower left.  The other two stars fit in the field as well.

Saturn is 2.4° to the upper right of θ Cap.

Make observations each clear morning to note the direction and relative speed of Jupiter and Saturn compared to their background stars.

While you’re outside with a binocular or small spotting scope, look at the moon and note the features along the terminator, the day/night line.  This is where the sun is setting and shows many shadows that indicate mountains, plains, and craters.

If you can hold the binocular steady, you might be able to note up to four of Jupiter’s largest moons on either side of the planet.

Evening Sky

2021, April 5: Mars is in the west after sunset, 5.1° to the lower left of Elnath.

One hour after sunset, Mars is over halfway up in the west.  It is moving eastward in Taurus.  The planet is above the “V” of Taurus that is made by Aldebaran, “the follower,” and the Hyades star cluster.  The Bull’s horns are marked by Elnath, “the one butting with horns,” and Zeta Tauri (ζ Tau on the chart).  Mars moves between the horns in several days.

This evening Mars is 5.1° to the lower left of Elnath.

The Red Planet sets over 5 hours after sunset.  As the evening progresses, the planet and starry background are lower in the sky.  Spot them within a few hours of sunset, before they are low in the western sky.

The “V” of Taurus represents the head and one eye of the Celestial Bull.  Bright Aldebaran is the 13th brightest star visible in the skies of Earth and 9th brightest visible from mid-northern latitudes.  The other four are visible from southern latitudes.  This star is over 60 light years away.

The Hyades cluster is over twice Aldebaran’s distance.  The “V” occurs from a chance position of a bright star a distant star cluster.

As an aside, many recent charts in these articles have included Capella, “the little she-goat.” This star is the 6th brightest star in the sky, and the 4th brightest visible from mid-northern latitudes.

Capella represents a goat that the Charioteer (Auriga) has in his arm.  A small triangle beneath Capella is sometimes referred to as “The Kids,” the baby goats.

Here’s more about Mars during 2021.

Read about Mars during April.

Detailed Note: One hour before sunrise, the moon (23.2d, 39%) is 14° above the southeast horizon.  Saturn is over 13° to the left of the lunar crescent.  Jupiter is 12.4° of ecliptic longitude east of Saturn.  In the starfield, Saturn is 2.4° to the upper right of θ Cap, while Jupiter is 1.9° to the upper left of Deneb Algiedi.  One hour after sunset. Mars is over halfway up in the west.  It is approaching the horns of Taurus, 5.1° to the lower left of Elnath.

Read more about the planets during April 2021.


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