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Episode 231: The April 2026 SkyGuide
Featuring Dr. Ian ‘Astroblog’ Musgrave
Will April bring a “Headless Comet” to our skies? In this monthly installment, Brendan O’Brien sits down with Dr. Ian Musgrave to navigate a particularly dynamic month for amateur and professional astronomers alike. From the unpredictable brightening of Comet C/2026 A1 (MAPS) to a rare “planet dance” in the morning twilight, this guide provides the precise timings and coordinates you need to look up with confidence.
Key Highlights for April 2026:
The Tangent: Why some comets receive “doom and gloom” social media treatment while others—like the spectacular Comet McNaught—pass by with little fanfare.
The Double Comet Watch: Tracking the stability of C/2026 A1 and the arrival of C/2025 R3 (PANSTARRS).
Morning Planetary Alignment: How to observe the tight grouping of Mercury, Mars, and Saturn (best seen around April 16th).
Evening Highlights: Venus climbing higher in the west and Jupiter’s alignment with the “Sickle of Leo.”
Lunar Phenomena: Specific windows to witness the Lunar X and Lunar A on April 24th.
The Tangent: Why some comets receive “doom and gloom” social media treatment while others—like the spectacular Comet McNaught—pass by with little fanfare.
Star charts and more at Ian’s Astroblog website
Transcript:
SFX: Satellite beeps 3 times …
Brendan : Welcome to Astrophiz with Brendan O’Brien.
Produced on Yorta Yorta, Pangarang and Kaurna country, we celebrate the first astronomers of this land.
Monthly, we explore the universe with the world’s leading scientists.
And here is Dr. Ian Musgrave with your April Sky Guide….
SFX: Morse code snippet …
Brendan: Hello, Ian.
Ian: Hello, Brendan.
Brendan: Great to be speaking with you again, Ian. And can you tell us, mate, what’s up in the sky for the month of April?
Ian: Well, quite a few things. Now, our planetary action has mostly moved the morning skies, but there’s still plenty to watch in the evening skies.
So Jupiter is still dominating the evening skies in the northwest. It’s setting around midnight, so it’s viewed most of the evening … and Venus is climbing higher in the twilight to become an evening star.
In the morning sky, we’ve got Mercury at its highest in early April above Mars, and Saturn is visible low in the morning twilight by mid-April. And then Mercury, Mars and Saturn form a planet dance in the early morning twilight in late April, which will be quite interesting to watch.
Now, what’s potentially very exciting is we may have two bright comets. C / 2026A1 (MAPS) in early April and C s?2025R3 (PanSTARRS) at the end of April.
We’ll talk about that in more detail later on.
Brendan: Yep.
Ian: We’ll go through the moon. So April 3 is thefull moon. April 10 is the last quarter moon, which is ideal for stargazing in the early evening. April 17 is a new moon, naturally ideal for stargazing. Then April the 24th is the first quarter moon …
… and this is when we have another chance to see the lunar X and lunar A. This will be seen in the early evening after astronomical twilight for the western and eastern and central states, but in the late twilight for Western Australia.
The moon is at apogee when it’s furthest from the Earth on April the 7th, and at perigee when it’s closest to the Earth on April the 19th. And daylight saving time ends on Sunday, April 5th. So those of you who are in daylight saving states get to turn back your clocks on the morning of April 5th. And this is also a good time to replace your smoke alarm batteries.
Brendan: Yep.
Ian: So let’s go to the evening sky. If you’ve been looking at the twilight sky in the past few weeks, you’ve been seeing Venus becoming visible in the horizon murk, and climbs higher in the early evening sky. So on the 19th, Venus is close to the two-layer-old thin crescent moon, and they’re about four degrees apart. Now on the 24th, Venus is just above the Pleiades, but you’re still going to need binoculars to see the Pleiades lower in the twilight. And on the 29th and 30th, Venus is just below the bright red star Aldebaran.
So around about 30 minutes after sunset at the beginning of April, Venus is quite obvious. And as it gets darker and it gets lower, it becomes more obvious. But naturally, as April wears on, it gets higher in the twilight. It’ll be much easier to see.
Brendan: Nice.
Ian: Yep. So turning to the northern sky, Jupiter is now in the northwest in the early evening, it’s forming a broad triangle with the bright stars Betelgeuse and Procyon, and then a narrower triangle with the stars Castor and Pollux, so it’s looking quite nice.
Right now, it’s also forming along with Pollux, Gamma Geminorum and Betelgeuse, so you’ve got a quite striking group of alignment of stars and Jupiter in the sky.
During the month, Jupiter becomes closer to Delta Gevimorum. And the pair are about 3.6 arc minutes apart by the end of the month. So that’s less than half a finger width. So on the 20th, Jupiter will be five degrees from a four day old waxing crescent moon.
And again, through binoculars, the dance of Jupiter’s moons will be always amazing to see.
And there’ll be a number of Jupiter moon events to observe in both binoculars and small telescopes.
Uranus is very low in northwestern sky at the end of astronomical twilight and may be difficult to pick up in binoculars if you’re looking.
So where all the planet dancing is happening is in the morning sky at the moment. So Mercury is climbing higher in the morning twilight. And this year, this month is the best time to see Mercury.
Now, Mercury will be furthest from the sun on the 4th of April. but it will be still relatively high for a number of days after that.
On the 16th, you’ve got an attractive massing with the three unaided-eyed planets just above the eastern horizon. Mercury’s at the top at four degrees from Mars and six degrees from Saturn in the line. As a bonus, the slender crescent of the Wayne 28-day-old Moon is nearby.
And then on the 21st, there’s another nice close encounter, with Mercury only half a degree from Saturn and 1.3 from Mars. Although because Mercury is sinking lower in the twilight, you may need binoculars to see the triple.
Now, Mars is low above the eastern horizon in the morning. And again, on the 16th, Mars will be lined up with Mercury and Saturn. It’s also going to be close to Neptune, but that’s not visible to the unaided eye. In the twilight, it’s probably not going to be visible in binoculars. So you’re just going to have to take my word for it.
But a detail that I did leave out when I was describing the line-up with Mercury, Mercury, Mars and Saturn are all within a six-degree circle, which makes them quite close indeed.
If you’ve got the binoculars or a strong telescope and a very low horizon on the 14th, Mars is only half a degree from Neptune. And then on the 16th, Mars is only three degrees from the Moon. And then on the 20th, Mars is only one degree from Saturn. And then again on the 21st, Mercury is 1.7 degrees from Mercury.
So some very close approaches. But again, because it’s relatively low above the horizon, you’ll need a fairly level, unobstructed horizon to be able to see this at the best. And by the 20th and 21st, you’ll probably need binoculars to see them all.
Brendan: Yep.
Ian: So as I’ve said, Saturn returns the morning twilight around mid-April. And I’ve just described the planets there, it’s sort of Saturn with all the others. So again, because Saturn is quite low to the horizon and relatively dim, you may need binoculars to see it.
So the big event is the comets, and I might leave that till later, and I’ll do that as my tangent.
But remember T. corona borealis?
Brendan: Oh, yes.
Brendan: Ian: It still hasn’t gone ‘bang’. It’s still down at the 10th magnitude. It’s now entering the northern… evening sky late, around about 10pm. So about 10pm, if you look for the orange star Arcturus in the northeast, you’ll see this thin circlet of stars just to the east of it.
And T-Corona borealis is in the right-hand side of the circlet where the stars turn down.
And so there’s no other bright stars in the region. So when it erupts, eventually… Maybe this year, maybe next year, maybe not. It will be easily visible.
Mira (Omicron Ceti) is theoretically unaided eye visible, but fading, but it’s really too close to the horizon to see effectively disappearing into the horizon of murk.
As you all note, both Orion and Taurus are beginning to sink into the western sky as the evening wears on, and they no longer dominate the northern sky. But another important classical constellation, Leo, is coming into the northern sky. Not as zodiacs are assigned Leo due to the precession of the equinoxes. Zodiacal Leo now covers Cancer. but the actual classical constellation of Leo. So if you look north, just to the western north, you can see the bright pair of Procyon, Alpha Canis Minoris, and Pollux, Alpha Gemini.
And these, as I’ve said before, form a triangle with Jupiter. If you look to the east of this triangle, the next brightest star you see is blue-white Regulus. This is the brightest star of the constellation Leo.
If you look down from Leo towards the horizon, you’ll see a trail of stars seem to form an upside down question mark. This is the sickle of Leo and represents the head of Leo the Lion.
And it’s from the centre of this sickle that the Leonid meteor shower comes.
Sadly, this year, there’s not going to be very many Leonids. It may be seven years before we see another decent Leonid outburst. The body of Leo lies further east, and so you can follow the stars down from Regulus to form this boxy rectangle from the Regulus and the second star of the sickle of Leo, which is relatively right Gamma Leo, forming the body of Leo.
Now, there’s lots of interesting galaxies in Leo, but you do need telescopes to see them, so I won’t dwell on that. But because Leo and Regulus lie close to the ecliptic, then you see occasionally Regulus gets very close to the Moon and occasionally is occulted by the Moon. It’s not going to happen this year, but… If you’re looking on the 26th of April, the waxing moon is very close to Regulus early in the evening. Very nice indeed.
Brendan: Cool.
Ian: Lots of planetary action and things to see in April.
Brendan: What about a tangent, Ian?
The tangent is going to be about two comets.
It’s not so much of a tangent, except that I’ll point out that we’ve had a number of bright comets in the past. Comet Elenin, Comet ISON, and even some fairly dim ones like Comet McNaught, which came close to Mars, where there’s been doom and gloom, where we’re expecting to have gravitational destruction and passing mass destruction as we pass through the tails of these comets, none of which came to pass. ELENIN sadly came apart before it reached the Sun, and Comet ISON came apart. as it was going around the sun. So there was a nice little puff of debris that was seen in space telescopes as it disappeared off into the distance.
Comet C2026A1 (MAPS) is a Kreutz family comet and it’s one of a group of related comets that pass very close to the sun.
No one’s coming up with doom and gloom about this one. We’re very excited. All the astronomers are excited about it, but nowhere in social media is people saying, “Oh, Comet C26 is going to cause solar flares or cause earthquakes when it lines up with planets” … and things like that.
So it’s not clear why some comets get the doom and gloom treatment and other comets get ignored even though they’re potentially quite important. I’ll also point out that one of the best comets of 2006 P1 McNaught, which was the amazing rooster tail … incredibly bright comet with this tail that took up a huge chunk of the sky for us in the Southern Hemisphere, had absolutely no one paying any attention to it in terms of social media and doom and gloom. That was one that put on an amazing show.
But let’s go back to C/2026A1 (MAPS). MAPS is for the automated telescope that discovered it. Now, Kreutz comets sometime back in the past, a very large comet disintegrated and fragments of this comet zoom around the sun very close. Most of the fragments are too small to see and just evaporate.
Other comets become very bright. and put on quite a show for us.
Now, people got very excited about 2026A1 because based on its approach to the sun, its apparent brightness and the speed at which it was brightening, people were going, “This was going to be a really, really nice comet”. And if you’ve been on social media, you have seen lots of graphs as people get very, very excited. Every time the comet gets a little bit brighter, a little bit brighter, “wow, fantastic!” … And then it stopped getting brighter. And then it started getting brighter again. So we thought, “Oh, maybe it’s about to disintegrate”. Maybe it’s not. It’s getting brighter again. It’s not getting brighter fantastically fast.
So it may not necessarily put on as good a show as people were hoping. And there seems to have been an eruption plume coming from the comet. So it could be that the comet’s unstable and is going to break up. Or it could be that because of its composition, it’s being very slow to heat up and is only occasionally erupting. So based on what we’ve been seeing, the two most likely outcomes is that the comet disintegrates before it reaches the sun, like Comet Ison, or that it breaks up after perihelion and forms a hairless comet like C/2021 W3 Lovejoy.
I don’t know if you remember Lovejoy.
Although it disintegrated, it had a very bright tail which for a couple of days after Christmas shone across the sky like a searchlight going from the horizon all the way up to the Magellanic clouds. So if it does a comet Lovejoy… It’ll be very nice, but will only be very nice for a short period of time. Now, the comet’s notoriously hard to second guess, and it may be that the comet will survive and will be decent.
You may be seeing on social media some predictions that they get up to magnitude minus 10, which is very, very bright, or even minus three or four, which is about as bright as Venus. But that’s when it’s very close to the sun. It’s going to be very, very hard to see. So by the time it’s in a good position for us to observe in the Southern Hemisphere, it will have abated substantially.
So probably the best chance we have of seeing it is around about -six when it’s far enough away from the sun, high enough above the horizon, 30 minutes after sunset, to be able to potentially see.
It may be visible in binoculars or it may be not visible at all. However, if there’s a decent dust tail, as twilight deepens, we may be able to see a tail sticking up from the horizon as the comet sinks below the horizon. It may be like 2024’s Comet G3. which largely, the head was largely disrupted. But at twilight, you could see the comet above the horizon. It was a faint streak above the horizon, but very obviously the comet. You had Saturn and Venus nearby, making everything look very nice.
This time, you’ve only got Venus, but Venus is a guide to where you can see the comet. If you look to where Venus is, very obviously close to the west, it looks a bit further west from Venus. That’s where the comet may appear if it hasn’t disintegrated. And over the coming days, as it gets higher in the twilight, we may be able to see the cometary head and or tail, or we may not, and it may only be a binocular comet, which is pretty exciting on its own accord.
It’s too early to tell.
I’m betting on a Comet Lovejoy-like Headless Comet, we’ll be able to see the tail above the horizon. It may be a long tail, it may be a short tail, depending on how dusty it is. But we cannot rule out that we may be able to see something really nice. We can also not rule out that it just disintegrates with a little sigh and we see nothing at all. That’s Comets for you.
Brendan: Well, fingers crossed, and we’ll all be going out for a look, Ian.
Ian: Indeed.
So that’s all right about Easter time. But late in April, we’ve got Comet 2025 R3 PanSTARRS.
Now, this is not predicted to be as bright as Comet C/2026A1, but it was getting a lot of press early on before A1 was discovered. Now, it’s not a sun-raiser. It’ll only get as close to the sun as the orbits of Mercury and Venus. And we’ve got some very wild magnitude predictions for this one. It’s anywhere between magnitude 8, which is about as bright as Neptune, so you’re not going to be seeing it in binoculars, and 2.8 which is about as bright as Delta Crucis. Again, the comet will be at perihelion on the 20th April and closest to Earth on April the 27th, and it may be visible from Australia from the 27th. The magnitude prediction maybe for a bit earlier on and it may have faded somewhat by the time of the 27th but it’s closest to earth at more modest predictions … if that’s correct we may be able to see it from the 30th again you’re looking at a very similar place if you look around Venus in the west from the 27th to 30th we may be able to see the comet faintly in the twilight as twilight gets darker.
Again, on Astroblog, I’ll put up some more detailed spotter charts with orbits and other information if we’re looking for them. But again, we could be in for a lot of disappointment or we could be in for some amazing things. We just don’t know.
Brendan: Well, fingers crossed, and I’ll be putting the Astroblog link into the show notes.
Ian: And when I put up the collections, I’ll link it back to the podcast when it goes up.
Brendan: Beautiful.
Ian: Yep. And so that’s April. There’s lots of things going on. And we can have, even if the comets don’t turn out to be fantastic, we’ve got a nice planet dance. We’ve got Venus looking really good at the horizon. Jupiter lining up with lots of interesting stars. So it’s going to be a very nice time for looking at the sky.
Brendan: Thank you very much, Ian ‘Astroblog’ Musgrave, we must all go out and look up.
Ian: Indeed. Definitely looking up. And now that I’ve mentioned the comets, we’re going to have terrible weather for the rest of the time.
Brendan: Yes, of course. Okay, thanks, Ian. Good night, mate.
Ian: Thank you very much, and good night to you too.
Brendan: In our next full episode, publishing April 15th, we explore the physics of our ionosphere with Dr. Maria-Theresia Walach who is a lecturer in space plasma physics, Maria-Theresia uses advanced satellite data to analyze the solar wind and the complex mechanisms that trigger auroral events.
We’ll be discussing how she predicts these displays and what the colours tell us about our atmosphere. Make sure you’re subscribed to Astrophiz so you’re the first to hear it.
And remember, Astrophiz is free, ad-free and unsponsored.
Keep looking up. Clear skies.
OUTRO: “Radio Waves”