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Planet Watch 2023

by Perry Pezzolanella

Nothing beats a starlit sky for relaxation and this year will offer plenty of opportunities, weather permitting. 2023 will have at least one bright planet in the evening all year long and will get busier as the holidays approach. There will be many lunar and planetary conjunctions, satellites, the International Space Station, and meteor showers to enjoy. There may even be a surprise aurora or comet!

There are no lunar eclipses during 2023 but there will be a slight partial on September 17, 2024, and a nice total lunar eclipse on March 13, 2025, to look forward to. The big event this year will be a partial solar eclipse on October 14 with the Sun 22% eclipsed at 1:17 P.M. The eclipse begins at 12:06 PM and ends at 2:29 P.M. paving the way for the big one April 8, 2024, as a total solar eclipse passes through Upstate New York!

Venus dominates the evening from January into August with Mars starting the year still bright after a good opposition in December. Both will attend Jupiter and Saturn in the evening sky until Saturn fades into the twilight later in January and Jupiter by March. Mercury peaks above the western horizon after sunset by late March and then Mars and Venus rule evenings for a long stretch until Saturn returns before midnight by July and Jupiter in August. Venus drops into the evening twilight during August and Mars fades away into the sunset glow by October. Saturn and Jupiter will dominate the evenings for the rest of the year to wrap up a hopefully productive year of planetary observing. Here is the breakdown for each planet in the evening sky during 2023:

Mercury: Always an elusive planet because it is very low on the horizon immersed in bright twilight, but it is easiest to see in the evening from March 27-April 17, being highest above the horizon on April 10. Mercury will grow steadily through this period from 6 to 10 arcseconds across as it approaches Earth, but its magnitude will dim from -1 to +2. It will go through phases like a tiny, coppery version of the waning Moon, from nearly full to a thin crescent.

Venus: This is a very good year for Venus in the evening as it will be much higher than in 2021. Venus will dominate the evening sky until August shining as bright as magnitude -4.5 by June. It will grow from a nearly full disc about 11 arcseconds across as the year begins into a huge, thin crescent nearly an arcminute high by late July. The orbital characteristics of Venus as seen from Earth during July will make it possible to see the thinning crescent in blue sky with binoculars and telescopes while the Sun is still up just before setting. Please be sure to take great care to hide the low Sun behind something to avoid accidently sweeping it into your eyes with your optics! It is unearthly to see the tiny white crescent in a blue sky especially if a few thin clouds are also in the field of view. Venus will dominate the morning sky for the rest of the year after inferior conjunction on August 13. The magnitude will range from -3.8 to -4.5 throughout the year.

Mars: A great start for Mars as it is just past its December 8 opposition and still shining high and bright in Taurus. It will start the year at 14.7 arcseconds across and magnitude -1.2 before shrinking and fading steadily the rest of the year. It will become lost in the evening twilight by October when it will be hardly more than 3.8 arcseconds across and shine at magnitude +1.7.

Jupiter: This will be another excellent year for Jupiter as it will be nearly the closest possible to Earth, about 365 million miles away, when it is at opposition in Aries on November 3. It will be 49.5 arcseconds across and sparkle at magnitude -2.9. The long nights (13-15 hours) and large size will allow for detailed viewing of the entire planet and the Great Red Spot as Jupiter rotates in less than ten hours. It should be possible to resolve the tiny discs of the larger moons, Callisto and Ganymede, and maybe even image dusky surface features. The sizes of all four moons might be possible to detect along with color differences: Callisto-gray, Ganymede-dull white, Europa-bright white, Io-yellow. Jupiter will become lost in the evening twilight by March 2024 as it fades to magnitude -2.0 and shrinks to 33 arcseconds across.

Saturn: The rings are closing, but the beauty remains with Saturn still a showstopper during the warm late summer evenings. It is at opposition on August 27 in Aquarius when it will be 19.0 arcseconds across and shine at magnitude +0.4. It will be a challenge to observe the Cassini Gap but observing the cloud belts and polar hoods will become easier in the years ahead with the rings narrowing. It might even be possible to find a few of the fainter moons such as Rhea, Dione, and Tethys. The largest moon, Titan, is readily visible shining around 8th magnitude and takes 15.9 days to orbit once around Saturn providing a fun project to plot its changing position. Saturn will slowly fade to magnitude +0.6 and shrink to around 15 arcseconds across by February 2024 when it becomes lost in the twilight glow.

Uranus: Turquoise is an unusual color for a planet but makes it easier to confirm Uranus as a small disc. It departs the evening sky by April but returns by September before midnight high up in Aries closing in on the beautiful Hyades-Pleiades region. It is at opposition on November 13 in Aries when it will be 3.8 arcseconds across and shine at magnitude +5.6. Uranus rises before midnight during September and descends into the evening twilight by April 2024.

Neptune: A distinguishingly bluish tinted tiny disc makes it easier to find Neptune among the stars. It fades into the western twilight by February, but returns before midnight in the east by August. It is at opposition on September 19 in Pisces when it will be 2.4 arcseconds across and shine at magnitude +7.8. Neptune will disappear into the evening twilight during February 2024. A finder chart for Uranus and Neptune will appear in the September issue of Telescopic Topics.

Pluto: The challenge is high for finding and confirming Pluto as it lies low below the ecliptic in Sagittarius and will only get lower and dimmer as it moves steadily away from Earth for the rest of the century. It is at opposition on July 22 in Sagittarius above a small asterism that looks like a fainter version of the Southern Cross to the east of the Teapot’s handle. Pluto is nothing more than a faint spark at magnitude +14.4 and will be only 0.1 arcseconds across.