Overview: Ceres Passes Close to Phi2 Ceti
If you’re looking for a rewarding sky event this Friday, turn your gaze toward the constellation Cetus. Ceres, the largest object in the asteroid belt, will be passing close to the magnitude 5 star Phi2 Ceti this evening. Observers should note that the best viewing window is about two hours after sunset, once the sky has darkened but before the Moon rises.
From an observing position at mid-northern latitudes, Ceres will hover about 15° high in the eastern sky as the night begins to unfold. It will continue to climb during the evening, meaning there are multiple chances to catch it—from soon after twilight through late-night hours, even if the Moon makes an appearance.
How to Find Ceres Near Phi2 Ceti
Begin by locating brighter magnitude 2.0 Diphda (Beta Ceti), also known as Deneb Kaitos. This star marks the end of Cetus’ brighter stage and sits roughly three times the mass of the Sun, currently in the late phases of its life. From Diphda, move your binoculars or telescope to the upper left (north) by about 7.3°, and you should spot Phi2 Ceti.
Tonight, Ceres lies just 10 arcminutes southeast (about one-third of a degree) of Phi2. With typical binoculars or a small telescope, you’ll be able to see Ceres at magnitude 7.6 hovering very close to the star. This pairing makes for an accessible target for amateur astronomers on a crystal-clear evening.
What If you miss it? Timing and Repeat Opportunities
If the early evening conditions aren’t ideal, don’t worry: the Moon’s rise will push the sky brightness up, but Ceres remains nearby the same star for a while. Tomorrow night, the Moon rises even later, and Ceres should still be close to Phi2, though the pair will be a bit higher in the sky. On October 11, Ceres will be about 10 arcminutes southwest of Phi2, offering another workable opportunity for observation with similar equipment.
Related Morning Sky: Io and Europa’s Transit Across Jupiter
For those who enjoy planetary highlights, an exciting event unfolds on the morning of October 11 as Io and Europa perform a striking double-ballet across Jupiter. By around 4:30–4:50 A.M. Eastern Time, Europa’s shadow appears on Jupiter, followed by Io’s shadow soon after. The shadows then move toward Jupiter’s eastern limb, with Io’s shadow first becoming visible on the disk at about 4:43 A.M. EDT and both shadows across the disk within minutes of each other. Europa’s transit begins at 6:43 A.M. EDT, with the shadows crossing the planet’s disk in quick succession by roughly 6:53 A.M. EDT.
If cloudy skies prevent catching the transit on October 11, there’s another opportunity the morning of October 18. Those in the western half of the U.S. may enjoy a clearer view then, so set your alarm and prepare a backup plan for a stargazing morning.
Practical Tips for a Successful Observation
- Time your session for about two hours after local sunset to catch Ceres in its best contrast near Phi2.
- Use binoculars or a small telescope; Ceres will appear around magnitude 7.6, just below naked-eye visibility.
- Be sure to account for the Moon’s rise time (Moonrise around 8:39 P.M. this evening, with Moonset later in the morning) to maximize dark-sky conditions.
- If you’re new to planet-asteroid spotting, start with Diphda as your anchor star and scan toward the northeast to locate Phi2 Ceti and the nearby Ceres.
Dates and Local Times
Sunrise: 7:06 A.M. • Sunset: 6:27 P.M. • Moonrise: 8:39 P.M. • Moonset: 11:37 A.M. • Moon Phase: Waning gibbous (78%)
Times are local for 40° N, 90° W. The Moon’s illumination reflects local time around 10 P.M.
Looking Ahead
For a broader look at this week’s sky, our Sky This Week column has more highlights—from planetary pairings to deep-sky targets—so you can plan your observing sessions accordingly.
