October 4, 2021: Before sunrise, the razor-thin lunar crescent is low in the eastern sky.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:51 a.m. CDT; Sunset, 6:27 p.m. CDT. Check local sources for sunrise and sunset times for your location.
An hour before sunrise, the thin crescent moon, 5% illuminated, is over 13° above the eastern horizon. It is near the haunches of Leo. It is 5.3° to the lower right of Chertan – “the two small ribs.”
At a distance of less than 200 light years, Chertan is about 150 times brighter than our sun.
Leo is climbing into the morning sky. Its shape is easy to locate, a backwards question mark connected to a triangle. The mark is the Lion’s head and the triangle makes the haunches and tail (Denebola).
Use a binocular to see earthshine on the night portion of the moon. Reflected sunlight from Earth’s oceans, clouds, and land gently illuminates the ground in the same fashion that the bright moon shines on the terrestrial landscape.
Photographers can capture this effect with a tripod-mounted camera that can take a time exposure of several seconds.
This image from November, 2020, shows a thin crescent moon with earthshine. The moon was 4%, similar to this morning’s illumination. The camera’s characteristics: lens, 140mm; ISO, 100, time, 2.5 seconds.
The meanings of the star names in these articles are from an article in the January, 1944 issue of Popular Astronomy by George A Davis, Jr.
Detailed Daily Note: One hour before sunrise, the crescent moon (27.4d, 5%) is over 13° up in the east, 5.3° to the lower right of Chertan (θ Leo, m = 3.3) and 2.4° to the upper right of Iota Leonis (ι Leo, m =4.0). Forty-five minutes after sunset, brilliant Venus is over 9° up in the southwest, 5.6° to the lower right of Dschubba and 12.8° to the lower right of Antares. The planet continues to step eastward along the ecliptic at about 1.1° of ecliptic longitude from night to night. Farther eastward, Jupiter is nearly 24° up in the southeast, 15.7° to the lower left of Saturn. The Ringed Wonder, 26.0° up in the south-southeast, is slowing to begin its direct motion in two evenings. Two hours after sunset, the giant-planet pair is higher in the sky. Use a binocular to see the starfield with the planets. Jupiter, over one-third of the way up in the south-southeast, is 3.5° to the lower right of dim μ Cap, 1.8° to the upper right of Deneb Algedi, and 1.4° to the upper left of Nashira. Saturn, nearly 29° above the southern horizon and east of the meridian, is 1.4° to the lower right of υ Cap.
RECENT PODCASTS
2021, October 29: Venus, Greatest Elongation
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.
2021, October 29 – November 1, Lion Moon
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!
2021, October 26-28: Morning Gemini Moon
October 26, 27, and 28, 2021: During the early morning hours, the bright gibbous moon appears in front of Gemini’s stars.
2021, October 26: Speedy Mercury’s Morning Best
October 26, 2021: Mercury is at its greatest morning appearance for the year. Look low in the east-southeast before sunrise.
2021, October 25: Caught Between the Horns
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.
Categories: Astronomy, Sky Watching
Leave a Reply