April 13, 2021: The crescent moon returns to the western evening sky after sunset. Mars is now above the Bull’s horns in the west after sunset.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:13 a.m. CDT; Sunset, 7:30 p.m. CDT. Check local sources for sunrise and sunset times for your location.
Thirty minutes after sunset, the new moon, that is only 3% illuminated, is about 12° up in the west. Use a binocular to first locate the lunar crescent. As the sky darkens, it appears lower in the sky. The crescent sets at about 100 minutes after sunset.
By an hour after sunset, the moon is still nearly 7° up in the west-northwest and nearly 17° below the Pleiades star cluster. Use a binocular to see earthshine on the night portion of the moon and to spot a dozen or so stars in the star cluster.
At this hour Mars is about halfway up in the west, well-above the “V” of Taurus made by the Hyades star cluster and Aldebaran, and nearly 40° to the upper left of the lunar crescent. Mars is above a line from Elnath to Zeta Tauri (ζ Tau), the Bull’s horns.
The Red planet is 4.1° to the upper left of Elnath and 3.7° to the upper right of Zeta Tauri. It sets over 5 hours after sunset.
Here’s more about Mars during 2021.
Read about Mars during April.
Detailed Note: One hour before sunrise, Saturn is 16.0° up in the southeast. Jupiter continues to slowly move away from the Ringed Wonder. This morning the gap is 13.3°. The Jovian Giant is over 11° above the east-southeast horizon. Use a binocular during several mornings to estimate the speed of each planet compared to the starry background. The changes are small but noticeable when observed across several mornings. This morning Saturn is 1.8° to the upper right of θ Cap. Jupiter is 2.5° to the upper left of Deneb Algiedi and 0.5° to the upper right of μ Cap. Thirty minutes after sunset, the moon (1.9d, 3%) is nearly 12° up in the west. Thirty minutes later, it is less than 7° in altitude. At this time, Mars is less than halfway up in the west between the horns of Taurus. It is above a line from Elnath to ζ Tau. The planet is 4.1° to the upper left of Elnath and 3.7° to the upper right of ζ Tau.
Read more about the planets during April 2021.
Newly released analysis from the Mars Reconnaissance Orbiter shows that the Arabia Terra region on Mars experienced powerful volcanic eruptions.
September 30, 2021: An hour before sunrise, the crescent moon is near the Gemini Twins.
September 29, 2021: The thick crescent moon is in the southeast before sunrise, approaching the middle of Gemini. The evening planet pack is visible after sunset.
September 28, 2021: This morning the moon, as it approaches its Last Quarter phase, is high in the south at the Gemini – Taurus border. The evening planet pack – Venus, Jupiter, and Saturn – brightly shine after sunset.
September 27, 2021: Before sunrise this morning, the bright moon seems caught between the horns of Taurus, Elnath and Zeta Tauri. The planet pack, Venus, Jupiter, and Saturn, are visible after sundown.