Jupiter Is Doing Something Rare Twice This May (Night Sky Preview)

Added: 2026-05-05

[00:00:00]This month Jupiter is putting on a show that most people have never seen.

[00:00:05]Two separate nights where you can watch two moons cast their shadows on the planet at the exact same time. And if you have a telescope, there's also a comet in the sky right now that is guaranteed to show up. No drama, no uncertainty, no it might just fizzle out. Simply point your telescope at it and it's there. We'll get to both. I'm Trevor from Night Sky Voyager. Welcome to your May night sky preview.

[00:00:37]I always like to start with the phases of the moon. May gives us two full moons in one month. The first full moon is the flower moon on May 1st, which will limit your deep sky observing early on in the month. Third quarter is May 9th and new moon is May 16th. That's your best window for observing right there in the middle of the month. And it's also right around when my local astronomy club is having our first star party of the year and we're all eager to get outside and hoping for finally some good spring weather.

[00:01:11]First quarter will be on May 23rd and the month closes with a blue moon on May 31st. A blue moon is simply when one calendar month has two full moons. It won't look any different, but it's a good excuse to go outside. Now, if you're a planet person, May is shaping up to be a solid month. Venus and Jupiter are both in the western sky after sunset all month long and they are genuinely hard to miss.

[00:01:40]Venus is blazing brightly near the horizon and Jupiter is the steadier one higher up in the sky.

[00:01:47]These are two of the brightest things that you can see in the sky and they're closing in on each other a little more every single night. Their actual conjunction will be on June 9th, so all of May is acting as a build-up. And Jupiter matters for another reason this month. Later in May, its moons put on one of the coolest live events you can watch through a backyard telescope.

[00:02:11]We'll come back to that later in the video. These two planets will form a photogenic grouping with the moon throughout the month, specifically May 17th through the 20th. There'll be a crescent moon near Venus on the 17th.

[00:02:25]It'll be sitting between the two planets on the 18th and the moon will be above Jupiter on the 20th. Three nights in a row worth going out for and good for wide field photos if that's something that you like to do.

[00:02:37]In the morning sky, Saturn and Mars are both low in the east before sunrise with the same caveat that we had last month.

[00:02:46]They'll be low against the horizon and fighting against bright twilight, making it more of a challenge than a reward.

[00:02:54]Saturn gets a little bit more accessible as May goes on, but neither of these planets are going to wow you this month.

[00:03:02]For meteor showers this month, May 5th will be the peak of the Eta Aquariid meteor shower and the hook here is worth knowing. These meteors are debris left behind by Halley's Comet. Every year in early May, Earth plows straight through that trail and this meteor shower is the result. The bad news this year is that the moon will be about 84% full at the peak of the meteor shower. Under good conditions, this is a fast and impressive one, but the moonlight is going to knock visibility down significantly. Probably not something worth going out for.

[00:03:37]Now, if April was all about comet drama, May is the opposite. Comet 10P, also known as Temple 2, is a periodic comet.

[00:03:48]That means it comes back around on a regular schedule, roughly every five and a half years.

[00:03:54]Its brightest apparition occurred in 1925 with an apparent magnitude of six and a half.

[00:04:00]In late April of this year, it was recorded around magnitude 11, meaning that in May you'll definitely need a telescope to see it. But there's no survival questions about it this time and no it might fizzle out. The only thing that can stop you from seeing it is clouds.

[00:04:17]In May, it will be passing through the gap between Aquila the Eagle and Sagittarius, but it will get brighter and brighter throughout the spring and summer as it approaches its perihelion in August. What you'll actually see through the eyepiece is a fuzzy, slightly asymmetric glow, a coma around a nucleus. It won't look like the dramatic tailed comets from the textbooks, but that's more commonly what comets look like in telescopes and there's something genuinely satisfying about knowing exactly what you're looking at. By late May, Temple 2 will be moving through the southern Milky Way, so you'll have a really rich star field backdrop to go with it. I'll put a link to a chart with the location of this comet in the description below.

[00:05:02]If you'd like to support the channel, please consider becoming a channel member or checking out the Night Sky Voyager merch store. The links for those are also in the description. Thank you and now back to the preview.

[00:05:14]For the constellation spotlight this month, we're looking at Bootes, the herdsman. And I picked it partly because it gives you one of the most useful navigation tricks in the night sky.

[00:05:26]Follow the curve of the Big Dipper's handle and extend that arc outwards. The first bright star that you'll bump into is Arcturus. We like to say arc to Arcturus. Arcturus is the fourth brightest star in the entire night sky and it has a beautiful warm orange gold color. But here's a very practical tip.

[00:05:46]Because it's so bright, it's one of the first stars to become visible at dusk, making it a great anchor star for your go-to alignment if you're running a computerized mount. I use it regularly for that. Once you've got Arcturus, the rest of Bootes fans out above it in a very recognizable kite shape with moderately bright stars. It's genuinely hard to miss. But I'll be up front with you. Bootes is not rich hunting ground for deep sky objects. There isn't much to find there at all. There's actually a region of space behind the constellation called the Bootes void, which is an enormous stretch that is nearly empty of galaxies. So, if you're sweeping around in Bootes and not finding much, there's a cosmic reason for that. What is worth your time is a star called Izar or Epsilon Bootes. I came across this object while researching for this video and I'm looking forward to observing it for my first time this month. To the naked eye, it's just a single point of light, but through the eyepiece it should become something else entirely, a double star with a striking color contrast between an orange primary and a blue white companion. William Herschel called it Pulcherrima, Latin for most beautiful, and I'm looking forward to having another double star that I can show at star parties that isn't Albireo because that one is very popular.

[00:07:13]For the binoculars target this month, step just west of Bootes into Coma Berenices or Berenice's Hair and look for the Coma Star Cluster. This is a case where binoculars actually beat a telescope because the cluster is so spread out that a telescope's narrower field of view works against you. This object is a wide field of loose scattered stars and it fills a binocular view very nicely. The Coma Cluster is one of those targets that reminds you how much is actually up there, which is a perfect setup for what's coming because May's final event is the most visually dramatic thing a backyard telescope can show you.

[00:07:55]All right. This is the big event for this month, which almost merited a video all its own. Jupiter's four large moons, the Galilean moons, orbit close enough to the planet that they regularly pass in front of the disk and cast shadows on the cloud tops. Through a telescope, you can see those shadows as small, sharp, black dots moving across the planet in real time. Now, if you could stand on Jupiter under one of these shadows, this would be an eclipse. Simply a moon passing between you and the sun casting its shadow down. From our perspective here on Earth looking at Jupiter, we're not seeing the moon, we're seeing the shadow that it leaves behind. This is an event called a shadow transit. So, what we're essentially watching is the footprint of an eclipse moving across another world. It's the exact same alignment that gives us eclipses here on Earth, you're just watching it from the outside. A double shadow transit is [clears throat] when two of those shadows are on the disk of Jupiter at the same time. It doesn't happen every month and this May, we get two chances, both involving the moons Europa and Ganymede. The first is the night of May 15th and into the 16th. Things get going around 11:00 p.m. Eastern.

[00:09:14]Ganymede's shadow is the larger, slower one and Europa is smaller, but moves faster. And it will actually pull ahead as you watch it progress.

[00:09:25]The best views for this event will be in the western US where Jupiter will be a little higher in the sky throughout the evening. The second is the evening of May 22nd where the shadow of Ganymede will start around 9:57 p.m. Eastern with Europa joining about two hours later.

[00:09:42]What makes this one interesting is that both of the shadows will arrive at nearly the same point at the disk at close to the same time. Pacific time zone observers will get the best geometry on this one again because it'll be higher in the sky. If you've never watched a shadow transit before, this is definitely the month to try for it.

[00:10:02]You'll absolutely need a telescope to see this one, and you should check your local time conversions to make sure that you can see it before you head out. But, the shadows are unmistakable once you know what you're looking for. It's a real treat, and I hope that I'm able to catch one of these this month. So, that's your May sky.

[00:10:21]Venus and Jupiter are building towards something special in the evening west.

[00:10:25]Comet Temple 2 is there and waiting for anyone with a telescope, and those two shadow transit nights are definitely worth planning around if you could get clear skies. If this preview was helpful, a like or subscribe really does help the channel grow. This is Trevor from Night Sky Voyager, wishing you clear skies.

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