December 1, 2022: Leo is high in the southern sky before sunrise during early December. After sundown, Jupiter and the gibbous moon make a striking conjunction.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:59 a.m. CST; Sunset, 4:21 p.m. CST. Check local sources for sunrise and sunset times for your location.
Here is today’s planet forecast:
With yesterday’s closest approach, Mars gleams brightly this morning in the western sky before sunrise. One hour before daybreak, find it about 20° up in the west-northwest, 5.4° to the lower left of Elnath – the northern horn of Taurus – and 11.4° to the upper right of Aldebaran, the constellation’s brightest star. The planet is nearly on an imaginary line between the two stars.
Mars continues to retrograde – move westward compared to the sidereal background. This is an illusion of Earth passing the more-distant planet. Earth passes between Mars and the sun on the 7th. This is known as opposition when Mars rises at sunset and sets at sunrise.
Three bright stars are in the eastern sky. Vega is about 10° above the northeast horizon; Arcturus is less than halfway up in the east; and Spica is less than one-third of the way up in the southeast.
Regulus – meaning “the prince” – is nearly two-thirds of the way up in the sky above the south-southwest horizon. At 80 light years, the star is nearly 200 times brighter than our sun. It is four times the sun’s diameter. Regulus is the 15th brightest star visible from the mid-northern latitudes.
Stars hotter than the sun emit tremendous amounts of energy through their surfaces. They release more energy per square yard than the sun. The result is that they are not as large as might be perceived. In contrast, redder stars release less energy per square yard of visible surface. To attain their brightness, they are very large compared to our central star.
When you look toward Regulus this morning, you are looking toward the sun’s early afternoon position during late August each year. Regulus is the closest star to the plane of the solar system and the sun’s apparent annual path through the zodiacal constellations.
Leo is one of a few constellations that resembles its namesake. The Lion faces westward and we see it in silhouette. A backwards question mark or sickle outlines the head of the lion. Regulus is at the bottom of the shape and in celestial artwork dots the animal’s heart. The haunches and tail are dotted by a triangle with Denebola – the tail – at the eastern edge.
Venus and Mercury are slowly emerging from bright sunlight. Mercury is east of Venus and setting later. Venus sets thirty-four minutes after the sun. Mercury follows four minutes later. The two inferior planets – those worlds closer to the sun than Earth – are joining the brighter outer planets for a five-planet display later this month.
The waxing gibbous moon, 65% illuminated, is visible before sunset and when night falls look for it near Jupiter. The moon is 3.6° to the lower right of the Jovian Giant. This is a striking sight!
In six evenings, on Mars opposition night, the Full moon covers or occults the Red Planet – a Martian opposition occultation!
At this hour Mars is less than 10° above the east-northeast horizon. Wait until later, when it is higher in the sky, to see it.
Saturn is about one-third of the way up in the south-southwest. It is slowly moving eastward compared to Deneb Algedi and Nashira in Capricornus. Saturn is 2.5° to the west (right) of Nashira. With the moon’s brightness, a binocular might be needed to see the two nearby stars.
Nearly three hours after sunset – after 7 p.m. CST in Chicago – Jupiter, with the moon nearby, is halfway up in the sky in the south. Saturn is over 20° up in the southwest and Mars is the same altitude – height above the horizon – in the east. It is noticeably above (west of) the imaginary line from Elnath to Aldebaran.
The three bright outer planets dot the ecliptic, like highway mileage markers, showing the plane of the solar system against the background stars.
Throughout the night Mars is farther westward. It is the second brightest starlike object tonight, after Jupiter, and noticeably brighter than Sirius – the night’s brightest star. Even though the planets are worlds, they appear as stars without a telescope.
By tomorrow morning, Mars is the lone bright planet in the western sky.
December 31, 2022: Mercury begins to depart the evening sky, leaving four bright planets – Venus, Saturn, Jupiter, and Mars on display for New Year’s Eve.Keep reading
December 30, 2022: The night’s brightest star, Sirius, is in the south at midnight as the year ends. The bright planet evening display continues as Mercury disappears into bright twilight.Keep reading
December 29, 2022: The evening planet display is ending as Mercury begins to retrograde and fade in brightness. Look for Venus, Mercury, Jupiter, Moon, and Mars after sundown.Keep reading