April 17, 2021: The bright morning planets, Jupiter and Saturn, are in the southeastern sky before sunrise. Bright Jupiter is passing a dim star. Through a spotting scope or telescope the distant star seems to intermingle with Jupiter’s largest satellites.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:07 a.m. CDT; Sunset, 7:34 p.m. CDT. Check local sources for sunrise and sunset times for your location.
Morning planets, Jupiter and Saturn are in the southeast before sunrise. Saturn is over 17° above the southeast horizon, about an hour before sunrise. The planet is slowly moving eastward compared to the starry background. This morning, it is 1.6° to the upper right of Theta Capricorni (θ Cap on the chart).
Bright Jupiter – over 12° up in the east-southeast – is nearly 14° to the lower left of Saturn. It moves faster through the starfields than Saturn. The Jovian Giant continues to open the gap on the Ringed Wonder.
This morning, Jupiter is 3.0° to the upper left of Deneb Algiedi (δ Cap) and 0.1° to the lower left of Mu Capricorni (μ Cap).
Use a binocular to see the planets with their starry backgrounds.
Point a spotting scope or small telescope with a low-power eyepiece at Jupiter. The planet’s four largest moons are easy to see. Mu Capricorni appears to be intermingling with Jupiter’s moons. The distant star – over a million times farther away than Jupiter – is along the same line of sight as the planet and its moons.
From North America and South America this morning, the star is near Ganymede. Other regions of the globe may spot the star in a slightly different place than is indicated on the chart.
Depending on the type of telescope, the image may not appear the same as depicted on the chart. Some telescopes invert the image and flip it left to right. Spotting scopes, as those used for bird watching or other terrestrial viewing, usually show the view as shown in the image.
Detailed Note: One hour before sunrise, Saturn is over 17° above the southeast horizon. Saturn slowly crawls eastward compared to the starry background. This morning, it is 1.6° to the upper right of θ Cap. Brighter Jupiter – over 12° in altitude above the east-southeast horizon – is 13.7° to the lower left of Saturn. The Jovian Giant moves to the east faster and continues to widen the gap to Saturn. Its motion compared to the starry background is a little easier to observe. Jupiter is 3.0° to the upper left of Deneb Algiedi and 0.1° to the lower left of μ Cap. One hour after sunset, the waxing crescent moon (6.0d, 28%) is over halfway up in the west in front of the stars of Gemini. While not in an ideal location or dark sky, the moon is 0.6° to the upper right of star cluster Messier 35 (NGC 2168). Use a binocular to see the moon with the cluster. If the binocular has a wide field, then place the moon and star cluster to the upper left of the field and fit Mars into the lower right. Use the binocular each evening to track Mars as it approaches the star cluster. Mars passes M35 on April 26, but the moon is very bright on that evening. This evening as the sky darkens and the celestial sphere turns westward, better views might be possible of the lunar slice and the cluster together. Mars is 5.8° to the lower right of the moon, 4.0° to the upper right of ζ Tau and 5.4° to the upper left of Elnath.
Read more about the planets during April 2021.
April 19, 2021: The first evening appearance of Venus for this apparition occurs this evening. Look for it low in the west-northwest about 20 minutes after sunset.
April 19, 2021: Venus begins to appear in the west after sunset. The moon lines up with Pollux and Castor, while Mars is above Bull’s horns in the western evening sky.
April 19, 2021: The bright morning planets, Jupiter and Saturn, are in the southeastern sky before sunrise. Capricornus is the starry background for this giant planet duo.
April 18, 2021: The crescent moon is high in the west after sunset among the stars of Gemini, below Pollux and Castor. Mars is above the Bull’s horns. Daylight is 13 hours, 30 minutes long.
April 18, 2021: The bright morning planets, Jupiter and Saturn, are in the southeastern sky before sunrise. Capricornus is the starry background for this giant planet duo. Daylight is 13 hours, 30 minutes long.