October 5, 2022: Before sunrise, Mars is with a congregation of bright stars. Mercury is in the east. Prepare to spot an asteroid near the moon after sunset tomorrow evening.
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.
Here is today’s planet forecast:
An hour before sunrise, step outside and look southward. The sky is full of bright stars that are visible on winter evenings. This is the best concentration of bright stars that is visible from the mid-northern latitudes. Other sections of the sky are seemingly empty in comparison.
Look carefully at the stars. They have slight but distinctive colors, ranging from the blue-white of Sirius, to the red-orange of Betelgeuse. A binocular or spotting scope helps to see the different colors.
In addition to Sirius and Betelgeuse, other bright stars are Rigel, Procyon, Castor, Capella, and Aldebaran.
Betelgeuse and Rigel are other obvious contrasts of star color. This pair is part of Orion. Sirius is part of Canis Major, while Procyon is part of tiny Canis Minor. Castor and Pollux are the Gemini Twins. Capella belongs to Auriga, while Aldebaran is part of Taurus.
Mars is approaching the Bull’s horns. The planet is about the same color as Aldebaran and Betelgeuse. It is slightly dimmer than Sirius. The Red Planet is high in the south-southwest, to the lower right of Zeta Tauri, the Bull’s southern horn.
Mars seems to be slowing its eastward march. It stops and reverses direction on October 30 and begins the illusion of retrograde. As our planet catches and moves between the sun and Mars, our line of sight from Earth to Mars, that normally progresses to the east, begins to move westward. Mars does not stop and move backwards in its orbit. Rather, this seemingly strange motion is an optical illusion.
Through a binocular, Zeta Tauri, and the Crab Nebula (M1 on the chart) are in the same field of view. The Crab is oval in shape and about the same brightness as the illuminated sky from outdoor lights. From urban and suburban skies, the nebula is a challenging view and easier from locations without bright outdoor lighting.
Jupiter is disappearing from the sky at this time interval before sunrise. It’s still low in the west at this hour, but within a day or so, is below the horizon at this time.
Mercury is putting on its best morning show of the year in the east before sunrise. At forty-five minutes before sunrise, it is over 7° up in the east. It’s not a high place to see it, but it’s the best it provides. The planet gains brightness each morning, but a binocular may be needed to initially locate it this morning. The planet is about 12° to the lower right of Denebola, the lion’s tail and 25° to the lower left of Regulus, the lion’s heart. Look each clear morning during the next week to see the planet brighten.
This evening the bright gibbous moon is near Saturn. An hour after sunset, find the Ringed Wonder 6.2° to the upper right of the moon.
This evening there is an infrequent opportunity to find easily the minor planet 4 Vesta. The full name of an asteroid includes its order of discovery. Vesta was the fourth discovered, first observed on Mar. 29, 1807 by Heinrich Wilhelm Olbers who had found 2 Pallas.
Tomorrow evening, spot the moon with an asteroid. Through a binocular, Vesta is 3.0° below the gibbous moon. Without the moon, Vesta is at the limit of human eyesight in a very dark location. Once you spot Vesta, to take away the lunar glare, move the binocular slightly to move the moon out of the field of view.
At one time, minor planets were thought to be from an exploded or fragmented planet. If all the irregular bodies could be put back together, the combined lump would be about the size of the moon.
Most of them are located in the “asteroid belt” between the orbits of Mars and Jupiter. Vesta revolves around the sun at 2.3 times Earth’s distance.
About a decade ago, the Dawn spacecraft studied Vesta up close. About 300 miles across, the spacecraft saw an irregular, cratered place, indicating a phase of bombardment early in the solar system’s history. The accompanying photo shows the view from the asteroid’s north pole, giving the irregular appearance.
Vesta is one of the most-massive asteroids, with nearly 10% of the mass of the asteroid belt. It is thought to have a differentiated interior. That is, it has a core and a mantle. The body was likely heated from radioactive decay.
It is one of the most-round asteroids. Dwarf planets, a newer class of planetary objects that includes Pluto, are round. Vesta nearly fits that definition.
Asteroids appear to be the source of meteorites that are found on Earth. Some meteorites are thought to be from Vesta. Large meteorites form craters, such as Meteor Crater in Arizona, when they impact our world. The moon’s cratered surface, as well as Mercury and Mars, is evidence of a period of impact throughout the inner solar system.
Vesta seems to be a more reflective object than other minor planets, making it at the edge of human eyesight, when the sun shines on it.
This evening, a star cluster appears in the same field of view with the gibbous moon and 4 Vesta. Cataloged as Messier 30 (M 30), the stellar bunch appears has a tiny cotton-ball when the moon is outside the field of view, otherwise it might be overlooked. The star cluster is thought to be about 40,000 light years away and about 100 light years across.
This evening the cluster is 3.9° to the lower right of the moon and 2.9° to the upper right of Vesta.
Comet hunter Charles Messier added it to his list of objects that are not to be confused with comets. This list of over 100 objects is the target of many backyard sky watchers. During early spring evenings, the entire list can be observed during one night, prompting some to engage in a Messier Marathon. Others are more sensible, locating the objects throughout the seasons to see all the “phantom comets.”
This evening, Jupiter is low in the east-southeast, following Saturn westward. By about midnight, Mars, Jupiter, and Saturn are strung across the sky. This evening the moon accompanies them.
- 2023, December 18: Pinched VenusDecember 18, 2023: Look for Venus between the Scorpion’s claws in the southeast before sunrise. The thick crescent moon is in the evening sky with Jupiter and Saturn.
- 2023, December 17: Celestial PairsDecember 17, 2023: Before sunrise, Venus passes Zubenelgenubi, a planet-star conjunction. After sundown, Saturn and crescent moon are paired, a planet-moon conjunction.
- 2023, December 16: Venus Clawed, Evening Crescent Nears SaturnDecember 16, 2023: Before daybreak, Venus is above the Scorpion’s southern claw. After nightfall, the crescent moon nears Saturn.
- 2023, December 15: Brilliant Morning Star, Evening Lunar CrescentDecember 15, 2023: Before sunrise, brilliant Venus approaches Zubenelgenubi, the Scorpion’s southern claw. The crescent moon returns to the western evening sky.
- 2023, December 14: Venus Nears Claws, Goodbye, Mercury!December 14, 2023: Brilliant Morning Star Venus nears the Scorpion’s northern claw, Zubenelgenubi. The thin crescent moon cues Mercury’s location in the evening sky.