October 5, 2021: Before sunrise, a very thin moon is visible in the eastern sky. The evening planet pack – Evening Star Venus, Jupiter, and Saturn – are visible at the same time after sundown.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:52 a.m. CDT; Sunset, 6:25 p.m. CDT. Check local sources for sunrise and sunset times for your location.
The bright stars of the Orion region dominate the sky during morning twilight. The sky’s brightest nighttime star, Sirius, is low in the south-southeast. As the sky brightens, a very thin crescent moon, 1% illuminated, is low in the eastern sky about 30 minutes before sunup. Use a binocular at a clear horizon to see it over 6° above the horizon. For readers who live in Hawaii, look for a thin waxing crescent moon after sunset tomorrow evening. This is also a binocular event. A crescent moon visible in the morning, followed by an evening crescent moon on the next evening is known as opposing crescents.
The planet pack – Venus, Jupiter, and Saturn – continues to brighten the evening sky.
Forty-five minutes after sunset, brilliant Venus is low in the southwest, approaching the head of the Scorpion. This evening, the Evening Star is 4.5° to the lower right of Dschubba – “the Scorpion’s forehead.”
In four evenings, Venus, the crescent moon, and the three stars of the head (Graffias, Dschubba, and Pi Scorpii, π Sco on the chart) are bunched together in the same binocular field, a rare event that occurs again on October 10, 2029.
After the grouping, Venus passes Antares on October 16.
When Venus is low in the southwest, bright Jupiter and Saturn are in the southeastern sky. The brilliant planet sets 106 minutes after sunset.
By two hours after sunset, Jupiter and Saturn are higher in the southern sky. At this hour, Jupiter is the brightest star in the sky, followed by Arcturus, Vega, and Saturn.
Use a binocular to find the starfields behind the planets. Both continue to retrograde in Capricornus, although Saturn’s apparent westward motion compared to the stars ends in less than a week.
Bright Jupiter is 3.5° to the lower right of Mu Capricorni (μ Cap on the chart), 1.9° to the upper right of Deneb Algedi, and 1.4° to the upper left of Nashira. Saturn is 1.4° to the lower right of dim Upsilon Capricorni (υ Cap).
As the sun sets earlier, find a local astronomy club or the neighborhood sky watcher to view the planets through their telescopes. Views of Jupiter and Saturn through a telescope are memorable events.
Detailed Daily Note: Forty-five minutes before sunrise, the razor-thin moon (28.4d, 1%) is about 4° up in the east, 11.3° to the lower right of Denebola (β Leo, m = 2.1). For sky watchers in Hawaii, with a binocular look for the evening crescent immediately after tomorrow’s sunset in the western sky. This event, a morning crescent followed by the next day’s evening crescent, is called opposing crescents. The shortest recorded observation of this event is less than 35 hours. The shortest intervals occur at the time of perigee. This month perigee occurs on October 8. Arcturus is at its Cosmic Rising – rising at the same time as the sun. They rise within two minutes of each other today. Forty-five minutes after sunset, brilliant Venus is over 9° up in the southwest, 4.5° to the lower right of Dschubba and 11.8° to the lower right of Antares. During the next ten days, watch Venus pass Dschubba and Antares. This evening through a telescope, Venus is an evening gibbous phase, 71% illuminated and 15.6” across. The planet sets 107 minutes after sundown. Farther eastward, Saturn is over 26° above the south-southeast horizon and 15.4° to the upper right of bright Jupiter. In five evenings, Saturn stops moving westward along the ecliptic and resumes its direct motion toward the east. Jupiter is 24.0° up in the southeast. Two hours after sunset, Saturn is nearly 29° above the southern horizon, east of the meridian, and 1.4° to the lower right of υ Cap. Jupiter is over one-third of the way up in the south-southeast, 3.5° to the lower right of μ Cap, 1.9° to the upper right of Deneb Algedi, and 1.4° to the upper left of Nashira.
October 29, 2021: Venus reaches its greatest elongation from the sun. It is in the evening sky with Jupiter and Saturn. The crescent moon and Mercury are in the eastern sky before sunrise.
October 29 – November 1, 2021: The crescent moon moves in front of the stars of Leo in the eastern sky before sunrise. Watch the moon appear lower and the phase shrink (wane) each morning. Also note that there is no Full moon on Halloween this year!
October 26, 27, and 28, 2021: During the early morning hours, the bright gibbous moon appears in front of Gemini’s stars.
October 26, 2021: Mercury is at its greatest morning appearance for the year. Look low in the east-southeast before sunrise.
October 25, 2021: This morning the bright gibbous moon seems to be caught between the horns of Taurus. Mercury is making its best morning appearance. The planet pack – Venus, Jupiter, and Saturn are in the evening sky.