2021, April 16: Morning Planets, Jupiter, Saturn

April 16, 2021: Jupiter and Saturn are the morning planets in the southeastern sky before sunrise.  Jupiter is the brightest “star” in the region.  Through a spotting telescope or small telescope, the star Mu Capricorni seems to intermingle with Jupiter’s largest moons.

2021, April 16: Morning planets Jupiter and Saturn are in the southeast before sunrise.
2021, April 16: Morning planets Jupiter and Saturn are in the southeast before sunrise.

by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 6:08 a.m. CDT; Sunset, 7:33 p.m. CDT.  Check local sources for sunrise and sunset times for your location.

Bright Jupiter and Saturn are low in the southeast before sunrise.  One hour before sunup, bright Jupiter is 12.0° up in the east-southeast.  Saturn is 13.6° to the upper right of Saturn and about 17° above the southeast horizon.

Both planets are gently moving eastward compared to the starry background.  Saturn is 1.7° to the upper right of Theta Capricorni (θ Cap on the chart).

Jupiter is 2.9° to the upper left of Deneb Algiedi (δ Cap) and 0.1° to the right of Mu Capricorni (μ Cap). On the scale on the chart above, Mu Capricorni is not shown as it is very close to Jupiter.

2021, April 16: The star Mu Capricorni (μ Cap) seems intermingled with Jupiter's moons.
2021, April 16: The star Mu Capricorni (μ Cap) seems intermingled with Jupiter’s moons.

Use a low-power eyepiece of a spotting scope or small telescope to see the star seem to mix in with Jupiter’s moons. From North America and South America this morning, the star is near the moons Europa and Io. Other parts of the globe see a slightly different view from what is displayed in the chart above.

The star is not actually near the moons, but it is along the same line of sight, over a million times farther away from us as Jupiter and its moons.

Tomorrow morning, Jupiter is passed the star.  Jupiter, its moons, and Mu Capricorni are still in the same low-power field of a spotting scope or telescope.

Detailed Note: One hour before sunrise, Jupiter is 12.0° up in the east-southeast, 2.9° to the upper left of Deneb Algiedi. Jupiter is 0.1° to the right of μ Cap. Use a low power telescopic eyepiece to observe the plane of Jupiter’s moons below the star.  Europa is to the lower right of the star, while Callisto is less than 0.1° to the lower left of the star.  Saturn – 13.6° to the upper right of Jupiter – is nearly 17° up in the southeast.  The Ringed Wonder is 1.7° to the upper right of θ Cap.  One hour after sunset, the crescent moon (5.0d, 20%) is less than one-half of the way up in the west, 5.6° to the lower right of Mars. The lunar crescent is 5.3° to the lower right of ζ Tau, while Mars is 3.8° to the upper right of the star.  With Elnath, the moon is 5.4° to the lower left, while Mars is 5.0° to the star’s upper left.  With a wide-field binocular it’s possible to fit the moon, Mars and one of the horns of Taurus in the field of view, but not all four objects simultaneously.  The gap between the horns is too large to fit into a binocular field.

Read more about the planets during April 2021.



Categories: Astronomy, Sky Watching

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