Transient Events That Can Give Us a Good Enough Reason to Get Outside and Do a Little Observing
November 2025
All month: the solar system favors the evening this month. Mercury sets at least 30 minutes after the Sun from Nov 1-14, on its way to inferior conjunction on Nov 20. It begins the month as a 7″ disk 58% lit at mag -0.2; by Nov 11 it’s more than 8″ wide, a 26% illuminated crescent shining at mag +0.6. Mars is also visible during early November, although very low in the sky, its 4″ disk glowing feebly at mag +1.4. Saturn now rises in the afternoon and sets in the wee hours. It opens November as a 19″ disk shining at mag +0.9, and closes the month 1″ smaller and 0.2 mag dimmer. The rings extend to 42″ as they close from 0.6° to their minimum tilt of 0.4° by month’s end before slowly beginning to reopen, so get your final views of a ringless Saturn while you can. Neptune spends the month 4° NE of Saturn as a 2″ blue disk glowing at mag 7.8. Uranus rises 2½ hours after Saturn, at 6:40 pm CDT on Nov 1 and 3:40 pm CST on Nov 30, its 4″ disk shining at mag 5.6 until morning twilight all month long. It sits just over 4° south of The Pleiades (M45) all month and reaches opposition on Nov 21. Jupiter begins the month as a target for night owls and early risers, breaching the horizon at 10:30 pm CDT, but moves into the late night timeslot by month’s end, when it rises at 7:30 pm CST. During the month its disk grows from 41″ to 44″ as it brightens from mag -2.3 to -2.5. It sets after sunrise all month. Venus lights the predawn sky with its 10″ disk at mag -3.9 all month, but it begins to slip into the solar glare by month’s end as it heads towards solar conjunction in early January. Late in the month, Mercury emerges in the morning sky as an 8″ wide, 31% lit crescent glowing at mag +0.2. Among the asteroids, 1 Ceres continues its trek through Cetus, an easy binocular or telescope target at mag 8. This month’s charts will show you where to find it.
Nov 1: we have morning and evening events to open the month, starting at 6:22 am CDT (an hour before sunrise) with mag -3.9 Venus 4° above the east horizon and mag +1.0 Spica (Alpha [α] Virginis) visible in binoculars the same distance below right of the blazingly bright planet. At 6:16 pm (a half hour after sunset), see if you can spot mag -0.1 Mercury just 3° above the horizon and 15° left of the spot where the Sun went down. You’ll almost certainly need binoculars or a telescope to see it – and if you look closely 6° to the right of Mercury, you might also be able to see Mars glowing at mag +1.5. You’ll have to be quick to spot both planets before Mars sets at 6:34 pm, followed by Mercury three minutes later. Then turn your attention farther east, where Saturn chases the gibbous Moon across the sky. The pair are separated by less than 5° in evening twilight and get closer as the night goes on, ending up only 3° apart when they set around 2:30 am.
Nov 2: daylight savings time comes to an end, making it even more clear that summer’s long gone.
Nov 4: Algol (Beta [β] Persei), the prototype eclipsing binary, reaches minimum brightness for two hours centered on 9:13 pm CST. Jupiter rises at 9:18 pm, just as the shadow of Io begins a trek across the planet that ends at 11:32 pm. The shadow of Europa takes the same stroll from 11:12 pm to 2:00 am, giving us a double shadow transit from 11:12 to 11:32 pm. Io itself transits from 10:30 pm to 12:45 am, and Europa does so from 1:40 to 4:31 am.
Nov 8: if you have an unobstructed western horizon, you might be able to spot mag +0.3 Mercury at 5:08 pm CST (a half hour after sunset), barely 2° up and 13° left of the spot where the Sun went down. If you’re quick, you can also try to nab mag +1.4 Mars 4° to Mercury’s right and mag +1.1 Antares (Alpha [α] Scorpii) 4° to its left before all three of them set 15 minutes later.
Nov 10: rising just before 10 pm CST, the 60% illuminated gibbous Moon crosses the late night sky 2° north of The Beehive Cluster (M44). Can you and your binoculars spot the cluster’s stars in the lunar glare?
Nov 16: the Leonids meteor shower peaks tonight, with the best views coming between midnight and dawn. The Moon won’t get in the way this time: it doesn’t rise until 4:18 am CST, and even then it’s just a slender crescent 2% illuminated. The Leonids result from a debris trail left behind by comet 55P/Tempel-Tuttle, which last passed through the inner solar system in 1998. Expect to see 10 meteors per hour from a dark site, and 3-5 from the suburbs. At 71 km/sec, the Leonids are the fastest of the fast-movers, often leaving persistent trains. They’re active from Nov 6-30, so keep an eye out for them all month, as well as the South and North Taurids (which peak on Nov 5 and 12, respectively, but remain active until Nov 25). Unlike the Leonids, the Taurids are slow movers (30 km/sec). They tend to be very bright and long-lived, with plenty of fireballs to boot, but they’re not prolific, with rates only around three meteors per hour even at a dark site.
Nov 17 and 18: we rarely see mutual events of Saturn’s moons, but a couple are on the menu when mag 10.5 Dione and mag 9.8 Rhea venture less than an arcsecond from one another at 8:00 pm CST on Nov 17 (with mag 13 Mimas even closer to Dione, for those with large scopes), while Dione and mag 10.3 Tethys appear to overlap one another at 7:25 pm on Nov 18. The involved moons are west of the planet both nights. Start watching an hour ahead of time on Nov 17 and a half hour ahead on Nov 18 to see the players gradually come together.
Nov 20: the shadow of Callisto, the most distant Galilean moon, is crossing the planet’s disk when Jupiter rises at 8:15 pm CST. The shadow completes its trip at 10:33 pm, followed by Callisto itself from 4:53 am until after sunrise, making this a rare month in which you can watch transits of all four of the Galilean moons. If you stay up for Callisto’s transit, be aware that because of its very low albedo, Callisto looks dark (more like a shadow than a moon) when viewed against the bright Jovian cloudtops. Meanwhile, the shadow of Io is also in mid-transit when Jupiter rises, giving us a double shadow transit until 9:47 pm, when Io’s shadow ends its trek. Io itself transits from 8:35 to 10:50 pm.
Nov 24: it’s Ganymede’s turn to march across Jupiter tonight. Its shadow starts the trip 15 minutes after the planet rises, crossing it from 8:13 to 11:23 pm CST, while Ganymede itself transits from 12:13 to 3:30 am. While that’s happening, Algol reaches minimum brightness again, over a two hour period centered on 10:56 pm.
Nov 25: early risers can grab their binoculars or telescope today to celebrate Mercury’s return to the predawn sky. At 6:21 am CST (a half hour before sunrise), the mag +2.0 planet is a thin crescent 9 arcseconds across, standing 4½° above the ESE horizon, just 1½° above and slightly to the right of bright round Venus (mag -3.9).
Nov 27: Algol again reaches minimum for two hours centered on 7:45 pm CST. A little later, the shadow of Io crosses Jupiter from 9:26 to 11:41 pm, followed by Io itself from 10:22 pm to 12:38 am.
Nov 29: at 5:11 pm CST, the dark limb of the 68% lit gibbous Moon seems to take a step backwards to gobble up mag 5.8 star XZ Piscium, with Saturn looking on from its post 4½° to the Moon’s lower right. Later, Europa’s shadow transits Jupiter from 9:18 to 11:08 pm CST, followed by Europa itself from 10:11 pm to 1:02 am.
Rick Gering / November 2025
http://naperastro.org/wp-content/uploads/2025/11/One-Good-Target.pdf
http://naperastro.org/wp-content/uploads/2025/11/Finding-Charts.pdf