Dídac Mesa Romeu
C/2022 E3 was discovered on March 2, 2022
, and initially reported as an asteroid candidate. One night later, Japanese observer Hirohisa Sato’s photographs of the object revealed a small coma, changing its status to a comet. More observations by additional observers confirmed Sato’s report. At the time, the 17th-magnitude speck was nearly 5 astronomical units from Earth, nearly identical to Jupiter’s average distance from the Sun.
On January 16–17, you’ll find our fuzzy friend in northeastern Boötes headed northwest at around 1.5° per day. Closest approach to Earth occurs on February 1st, when the comet will whiz past at 42 million kilometers (26 million miles). Perihelion (closest approach to the Sun) occurred on January 12th at 166 million kilometers (103 million miles).
With an inclination of 109°, Comet ZTF E3's orbit is steeply tilted to the plane of the planets. It's headed southward in January and will cross the ecliptic plane on February 12th.
As Comet ZTF E3 closes in on our planet in the coming weeks, its apparent motion across the northern sky and altitude increase quickly. The comet becomes a circumpolar object for the northern states and Canada around January 17th and for the rest of the continental U.S. on January 25th. Come month’s end, Comet ZTF will be trucking along at the rate of 6.5° a day! That’s better than ¼° per hour, making its motion relative to the background stars obvious through a telescope after just a few minutes. Even 10× binoculars will reveal movement in an hour or two.
The comet speedily mounts the northern sky this month as seen from latitude 45° north. Positions are shown for 11 p.m. CST. Remember to use binoculars as the comet will likely appear rather faint from light-polluted locations.
Stellarium with additions by Bob King
In this Spanish language version, the comet's position is shown every 3 nights for latitude 35° south at 10 p.m. CST. Stars are plotted to ~6.0 magnitude. From mid-southern latitudes, Comet ZTF will first become visible low in the northern sky in Auriga in early February. The position of Mars (Marte) is shown for Feb. 7.
Stellarium with additions by Bob King
From latitude 40° north the comet stands 10° high in the northeastern sky on the night of January 16–17 at local midnight. That improves to 21° five nights later on January 21st. During much of January, observers in the northern U.S. will see the comet higher up earlier in the night compared to those in the southern part of the country, where the best views will be after 2 a.m. local time. Viewing becomes more equitable across the U.S. by late January when the object will be circumpolar for everyone. The table below addresses Comet ZTF’s continually changing circumstances as it climbs higher and higher while playing tag with the Moon.
|Dates||Comet 25° or higher, minimal Moon||Moon phase|
|Jan. 16–24||Midnight till dawn||Waning crescent to waxing crescent|
|Jan. 24||11 p.m. till dawn||Waxing crescent|
|Jan. 25||10 p.m. till dawn||" "|
|Jan. 26||9 p.m. till dawn||" "|
|Jan. 27–28||7 p.m. till dawn||" "|
|Jan. 29–Feb. 2||Early morning hours after moonset||First quarter to waxing gibbous|
|Feb. 3–5||Moon interferes all night||Waxing gibbous to full Moon|
|Feb. 6–22||Moonless window opens again — evening hours||Waning gibbous to waxing crescent|
Here are the best times for viewing the comet through late February from latitude 40° north. "Best" is defined as minimal interference from moonlight with the comet at least 25° high. Southern observers will see the comet a little lower; northern ones higher. Bolded dates are nights with little to modest moonlight and convenient evening
First-quarter phase occurs on January 28th, when the Moon will set around 12:30 a.m. (on January 29th). A half-moon isn’t much of a comet-killer especially when it shines at the opposite end of the sky. However, by month’s end, the waxing gibbous Moon in Taurus and then Gemini will diminish the comet’s appearance if you plan to observe it before
midnight. Fortunately, the Moon sets in the wee hours through February 2nd, leaving dark-sky windows to observe and photograph the bearded visitor at its closest and brightest.
The comet's short but prominent dust tail — seen here on January 3, 2023 — is fan-shaped and easily seen in a telescope. It currently points to the northwest. The much fainter ion tail (right) extends to the north-northeast.
By early February the comet is firmly ensconced in the evening sky. It slides about 1.5° southwest of Capella on the evening of February 5th, the night of full Moon. The following evening it brushes Zeta (ζ) Aurigae in the Kids asterism. While the compact nuclear region will miss the star by ~10′, the fluffy coma may temporarily engulf it. Mars gets a visit on the night of February 10–11 when the comet cruises about 1.5° northeast of the planet for observers in the eastern half of the Americas. West Coast viewers will see them just 1° apart. The two bodies, one golden-orange, the other green and turquoise, should make a fine color contrast in time-exposure photos. Come Valentine’s Day (February 14th), Comet ZTF will have faded to about magnitude 7.0 and glow in a moonless sky around 1.5° east of Aldebaran in Taurus.
Then it’s back home for this interloper. Although its inbound journey took some 50,000 years, the return voyage to the Oort Cloud is expected to be in the millions. Don’t forget to wave “goodbye!” You can stay abreast of the comet’s magnitude, coma diameter, and more at the Comet Observation Database
(COBS). Click on the Recent Observations link, then search for C/2022 E3. Another excellent source is Weekly Information about Bright Comets
. Happy hunting!
January 16, 2023 at 3:43 pm
Finally, the real story! Thank you thank you thank you! I have been trying to battle the mainstream media (and many "science") hyped posts but it is a losing battle! One of the worst things is that I have not seen another article that talks about the moon being a problem, and it is a big problem with this comet for anyone who wants to see it naked eye. The one thing I would like to see is a photo showing what it looks like in say an 8 inch scope.