But, you wonder, which planets are out tonight and where should I look to see them?
Well, showing you which planets are visible tonight and where to look for them is what this guide is all about.
Use the ‘Quick Navigation’ box to quickly get details on the planet of your choice.
Let’s jump in and discover which planets we can see tonight.
Introducing… The Planets
There are eight official planets in our solar system (if you thought there were nine, read this). We live on one of them, which leaves seven for us to look at in the night sky.
From the sun outwards, they are Mercury, Venus, [Earth], Mars, Jupiter, Saturn, Uranus, and Neptune.
The Five Visible Planets
The five planets closest to us are bright enough to be easily seen in the night sky with the naked eye. For that reason, these are collectively known as the five visible planets. From closest to the Sun, outwards, the five visible planets are:
All of the planets look wonderful through a telescope, with many different and dynamic features to try and observe.
If you’ve never seen the awesome sight of Jupiter’s cloud belts, Saturn’s rings, and Martian ice caps, then it’s time you checked out our reviews of the best telescopes to see the planets (opens in a new tab).
The Outer Planets
The two outermost planets of the solar system are much trickier to see than the five discussed above.
The closer of these ice giants, Uranus, is technically visible to the naked eye but, unless you know where to look, it is not bright enough to be distinguishable from the background of brighter stars.
Neptune, the most distant planet in the solar system, can only be seen with binoculars or a telescope.
We show you how to see if Neptune and Uranus are visible tonight towards the end of this guide.
Seeing The Five Visible Planets in 2021
All 5 visible planets have great seeing at some point during this year, which you can see at a glance by scrolling down to the table below.
Before reading it though, it helps to understand why there are times when the planets are well placed for observing and others when they are not visible.
Discover our reviews of this year’s best telescopes
Imagine the five planets split across two groups, the inferior and superior planets:
- Inferior Planets: Mercury and Venus lie inside Earth’s orbit, closer to the Sun than we are
- Superior Planets: Mars, Jupiter, and Saturn lie outside Earth’s orbit, further from the Sun
When to See the Inferior Planets
Mercury and Venus orbit the Sun inside Earth’s orbit, which means a number of significant things:
- They orbit faster than Earth, so they change position in the sky quickly
- They present crescent phases to us like the Moon because we can see parts of the planets’ surfaces that are not facing the Sun
- The best time to see them is at ‘greatest elongation’, which is when they appear to be at their farthest from the sun as we see them.
The worst time to see the inferior planets is when they are in conjunction. This is the name given to the moment when Earth, the Sun, and the planet are all in a straight line.
There are two types of planetary conjunction:
- Superior conjunctions happen when the planet is on the opposite side of the Sun from us, i.e. the Sun is in between us and the planet, and
- Inferior conjunctions are when the planet is in the middle, i.e. it sits between us and the sun
See both types of conjunction highlighted with the red rings on the diagram below.
The inner planets are invisible to us at and near conjunctions because they are lost in the glare of the Sun.
The rare exception to this is when an inferior conjunction happens and the planet is on the same plane as us and the sun. When that happens we see a spectacular transit of Venus or Mercury across the face of the Sun.
Sadly, they are quite rare. To see Venus pass in front of the sun you need to be a young person, and ideally not even born yet because there are 96 years to go before the next one.
Fortunately, we all stand a better chance of seeing little Mercury cross the Sun’s disc but we still need to wait until 2032.
The best time to see Venus and Mercury is when they are at greatest elongation, shown inside the pink rings on the diagram below. At greatest elongation, these planets are as far from the Sun as they get in our sky.
That still normally means challenging viewing for Mercury. The tiny planet orbits so close to the sun that it is rarely visible for more than an hour before sunrise or after sunset, so we only ever find the planet in the glow of dusk or dawn.
Venus orbits further out, so we do get to see it against the inky blackness of night, but it too sets or rises within a few hours of the Sun.
This brings us to the final point you need to be aware of as a planet hunter: at greatest eastern elongation, the planet is visible after sunset. At its greatest western elongation, we’ll see the planet in the morning, before sunrise.
When is the Best Time to See A Planet?
The diagram below shows an idealized position of inferior planets (inner ring) and superior planets (outer ring) hitting conjunction, greatest elongation, and opposition with Earth (blue circle, middle ring).
You can see that at both superior and inferior conjunctions the planet is in the same line of sight as the Sun, so we can’t see it in the sky; the Sun’s glare is too bright.
The best time to see superior planets is at opposition because they are directly opposite the sun but behind Earth (green ring in the diagram), which makes them visible in the sky all night long. The best time to see inferior planets is at their Greatest Elongation.
When to See The Superior Planets
Mars, Jupiter, Saturn, Uranus, and Neptune all orbit further away from the Sun than our planet does. For this reason, these planets are called superior and they have a different character in the sky from the inferior Mercury and Venus:
- They take longer to complete an orbit of the Sun than Earth, which makes them appear to move only slowly across the night sky, i.e. they only move a short distance compared to the background constellations
- Being inside their orbit, we can only see the side facing the sun, so they are always a complete disc. i.e. we never see them in crescent form
- The best time to see the superior planets is at opposition
Just like Mercury and Venus, the superior planets also form [superior] conjunctions with Earth and the Sun. And, unsurprisingly, they too are invisible at this time because they are lost in the Sun’s glare.
The best time to see the outer planets of the solar system is at opposition. If you refer to the green circle in the diagram above, it’s easy to see why.
Unlike the inferior planets, the outer planets never pass between Earth and the Sun. At opposition, we sit directly between them and the Sun. Think of it as having the Sun ‘behind’ us while the planet is ‘facing’ us.
This is an awesome time for planet-watching because a planet at opposition is visible all night long and highest in the sky (transiting) around midnight!
We get hours to see the planet high above the horizon during the hours of darkness. This often coincides with the planet’s closest approach to Earth too, offering even more spectacular views.
Okay, that’s more than enough understanding of why we can or can’t see the planets tonight. Let’s turn now to the most important part of this article: which planets can we see tonight?
Which Planets are Visible Tonight?
To find out “what planets can I see tonight?” use the table below which is the perfect quick solution for you.
It shows which of the five visible planets can be seen tonight for each month in 2021. It includes opposition dates for Mars, Jupiter, and Saturn, and greatest elongation dates for Mercury and Venus.
For each of the five visible planets, we show you whether it is visible in the evening (E) or morning (M).
During opposition months, the planet will be visible all night. Where there is ‘—‘ in the table, the planet is not visible during this month.
|Aug||—||E||E||Opp 19th||Opp 02nd|
|Oct||mGE 25th||GE 29th||—||E||E|
mGE = Greatest Elongation visible morning, eGE = Greatest Elongation visible evening, Opp = Opposition, M = Morning, i.e. rises after midnight, E = Evening, i.e. rises before midnight, — = Not Visible. For Mercury, only Greatest Elongation dates are shown but the planet will be visible for 1-2 weeks on either side of that date.
Planets Visible Today – The Details
Now you know which planets are visible in the sky tonight, let’s look at them individually for more detail on where to see them throughout 2021.
Is Mercury Visible Tonight?
For the smallest planet in the solar system, you may be wondering can we see Mercury from Earth, and the answer is a resounding yes! You can see Mercury without a telescope if you know when and where to look. However, of the five brightest planets, Mercury is definitely the trickiest one to glimpse.
For the best chance of success, find an elevated position, e.g. a hill that overlooks an open horizon. Mercury skirts so close to the ground – even at its best – that trees and buildings can prevent you from seeing it.
Where Can You Find Mercury?
The challenge to seeing Mercury comes from the short distance between it and the Sun, and the rapid orbit the planet has. Mercury orbits the Sun in only 88 days, so it completes well over four laps of the sun for every one of ours.
Mercury is so close to the sun that we can never see it in true darkness. Its proximity to the sun also means that the little planet is never very high in the sky – it rarely rises more than 10° above the horizon after sunset or before sunrise. Ten degrees is about the width of your fist at the end of your outstretched arm, i.e. it’s not very high.
Our time to see it is also limited. Even at its best seeing, Mercury is usually only visible for up to an hour before sunrise in the morning or after sunset in the evening. And, because of its rapid orbit, we don’t get to see Mercury for many days in a row either before it returns to the Sun’s glare.
Because Mercury is near the Sun, it’s visible in the west straight after sunset and in the east immediately before sunrise.
Mercury Seeing Challenges:
- Mercury. Yes, your first challenge is to see the planet itself. Whilst it is bright, it’s always in the glare of the dawn or dusk low towards the horizon. Seeing the planet Mercury is a great first achievement!
- Mercury’s phases. What is worth looking out for is the crescent of Mercury. Sky & Telescope Magazine always carry an almanac of how much of the surface is illuminated. (Read our Sky & Telescope review here).
When Can We See Mercury from Earth?
Mercury has a speedy orbit, so it does not hang around long and we have to grab opportunities to see it. Thankfully, Mercury has six greatest elongation events this year, three each in the evening and morning.
Mercury’s greatest elongations of 2021 occur on:
- January 23rd, best viewed after sunset
- March 06th, before sunrise
- May 17th, after sunset
- July 04th, before sunrise
- September 13th, after sunset
- October 25th, before sunrise
The next elongation doesn’t happen until January 07th, 2022.
Remember, because Mercury is a speedy planet, seeing stays favorable only for a few days on either side of these dates. For the rest of the time, Mercury is lost in the Sun’s blinding glare.
For more details click this link for our dedicated guide to seeing Mercury with a telescope.
2021 Mercury Viewing Calendar
Always be careful when searching for and viewing Mercury, especially if using binoculars or a telescope. The Sun is never far away and will severely damage your eyes if you look at it – even a glimpse of it with binoculars or a telescope can blind you.
January: Mercury is in Capricornus at the start of 2021. It’s an evening ‘star’ best viewed between the 15th and 28th of the month.
February: There is limited visibility at the beginning of the month as dusk begins. At the end of February, Mercury rises before the Sun with okay visibility.
March: Mercury reaches greatest elongation on March 06th and is almost 11° above the horizon at sunrise. However, it is only 4° above the horizon 40 minutes before sunrise, making this a tough observing month.
April: In the last days of April, we can find Mercury a few degrees over the west/northwest horizon, in Aries, as dusk sets in.
May: One of the best viewing opportunities of 2021 comes around the greatest elongation of the 17th. On that evening, Mercury is 12° above the horizon 40 minutes after sunset, find it in the constellation of Taurus. Observation is particularly good from the first day of May until around the 21st.
June: At the end of June, Mercury is once more a morning ‘star’ still set against the backdrop of Taurus. Viewing is poor though as the planet is just 6° above the northeast/east horizon 40 minutes before sunrise on June 30th.
If you’re looking for more detail than this, take a look at the Virtual Astronomy Club. Each month we issue detailed guides for observing Mercury, including exactly where to look each day.
July: Greatest elongation occurs on the fourth of the month, but seeing is far from impressive. Look low on the northeast/east horizon 40 minutes before sunrise. Mercury remains viewable until the last week of the month.
August: There is no visibility of Mercury in August 2021.
September: Although greatest elongation is reached on the 13th of the month, viewing is very poor because the angle of the ecliptic (the line the planets travel across the sky) is very shallow. Even on the 13th itself, Mercury barely grazes the western horizon 40 minutes after sunset.
October: The last greatest elongation of the year for Mercury is a good one. On the 25th, find the planet 10° above the eastern horizon, in Virgo, 40 minutes before sunrise. Best viewing lasts from Oct 21st to Nov 06th.
November: Good morning viewing stays with us for the first ten days of the month and then Mercury moves too close to the Sun for us to observe it.
December: As the year ends, we can grab our last evening glimpses of Mercury. Look southwest 40 minutes after sunset to see Mercury 6° over the horizon in the final few days of the month. It’s in Sagittarius now, heading towards greatest elongation on January 07th, 2022.
Is Venus Visible Tonight?
The next planet out from Mercury is Venus. After the Moon, Venus is the brightest object in our night sky.
Like Mercury, Venus orbits relatively close to the Sun and is known as either a morning or evening ‘star’ because it either rises in the morning before the Sun or sets after it in the evening.
Unlike Mercury, Venus is far enough from the sun that we can see it in the darkness of nighttime and not just in the glow of dawn or dusk.
Venus also has crescent phases, like our own Moon, which can be seen through a small telescope. This is the only feature to observe on Venus because it has no moons of its own, nor any visible surface features.
Where Can You Find Venus?
Like all planets, Venus is found on the ecliptic but never strays too far from the western horizon when it’s an evening star or the eastern horizon in the morning.
The planet is unmistakably bright, shining much brighter than any other object in the night sky which makes it easy to view, even with a pair of binoculars.
At its furthest from the Sun, Venus can spend a few nights where it is visible all night long. From central latitudes of the US, it can climb about 30° above the horizon.
For more details click this link for our dedicated guide to seeing Venus with a telescope.
Venus Seeing Challenges:
Crescent Venus. Looking at the planet through a telescope, you’ll be able to see the phase of this planet, from crescent to gibbous. See its disc size change as Venus moves closer to and further from Earth.
- See Venus in the day! Yes, it is bright enough to be seen when the sun is in the sky, but you need to know where to look and have keen eyes
- See a shadow cast by Venus’s light. On a moonless night, it is the brightest object in the sky and, at a dark site, it is possible to see shadows cast by the planet
When Can We See Venus from Earth?
Venus only has one greatest elongation in 2021, on October 29th, which is best viewed after sunset
2021 Venus Viewing Calendar
January: Venus begins the year in the morning skies against the backdrop of Sagittarius, but is only observable for the first week of the year. After that, it moves too close to the Sun and we lose visibility of it until it re-emerges in May evenings.
February: Venus is not visible this month because it is too close to the Sun.
March: Venus is not visible this month because it is too close to the Sun. The planet reaches superior conjunction, which is when it is directly behind the Sun from our perspective, on the 26th of the month.
April: Venus is not visible this month because it is too close to the Sun.
May: Finally, after a third of the year hiding near the Sun, Venus can be glimpsed above the northwest horizon in the last two weeks of May. See it shining at magnitude -3.9 in Taurus, 6° above the horizon. Its disc is over 95% illuminated.
June: Venus slowly ventures into the night sky but we still don’t have great visibility this month. By mid-June, Venus is less than 10° above the west/northwest horizon 40 minutes after sunset. Find the 10-arcsecond disc of the planet in Gemini, shining at magnitude -3.9 and 93% illuminated.
If you’re looking for more detail than this, take a look at the Virtual Astronomy Club. Each month we issue detailed guides for observing Venus, including exactly where to look each day.
July: Moving into Leo, Venus is still only 10° over the western horizon shortly after sunset. Its brightness is unchanged at magnitude -3.9, but the disc has grown marginally and is only 86% lit in at mid-month.
August: Little changes are apparent in the telescope, even if the planet still appears low in the western sky after sunset against the constellation of Virgo. Now the planet is only 3/4 illuminated but has grown to 14 arcseconds wide which brightens it to magnitude -4.0.
September: This month Venus is still in Virgo, just 10° over the southwest horizon forty minutes after sunset. It has brightened again to magnitude -4.1 because it is closer to us making its disc 17 arcseconds wide. That disc, however, is less than two-thirds illuminated.
October: Venus reaches greatest elongation on the 29th, the furthest it gets from the Sun in our sky. However, the ecliptic is shallow and Venus is just 11° above the southwest horizon, in Ophiuchus, an hour after sunset. The Venusian disc is only half-lit now, but it has grown again to 23 arcseconds across and shines at a dazzling magnitude -4.3.
November: Returning to Sagittarius, Venus is 13° above the southwest horizon an hour after sunset. In the middle of the month, it has brightened again to magnitude -4.5, even though its disc is less than 40% lit. It’s brighter because it’s closer to us; its disc is now 33 arcseconds wide.
December: As the ecliptic moves more perpendicular to the horizon, December provides the best views of the year for Venus. Still in Sagittarius, Venus is 13° over the southwest horizon an hour after sunset. The planet is 50 arcseconds wide, shines at magnitude -4.7, and is just 15% illuminated.
Is Mars Visible Tonight?
Passing our home planet, we begin the journey through the superior planets with Mars.
Famous to everyone, astronomer or not, the ease with which it can be picked out in the night sky varies. But, if you’ve ever wondered ‘can you see Mars without a telescope?’ the answer is a definite Yes!
Mars reaches opposition every two years or so, the last time was in October 2020 and the next one is in October 2022. Sadly, this makes 2021 a poor year from Mars observations.
Where Can You Find Mars?
Mars begins 2021 as an evening object in the constellation of Pisces but after just five days it moves into Aries. It then moves through the zodiac constellations (more detail below) before reaching Cancer in June.
Soon after that, Mars moves too close to the Sun for us to see it. It reaches superior conjunction on November 17, when it will be directly behind the Sun, and remains invisible to us until the very end of the year.
Click here for our dedicated guide to seeing Mars with a telescope.
Mars Seeing Challenges:
There are lots of features we backyard astronomers can look for on the Martian surface but many of them are not available to us this year given the distance of the planet.
- Redness of the disc. It is apparent in any size of telescope
- Gibbous Shape. Mars does not show phases like the inner planets, but it is close enough that Earth casts a shadow on it at various times on its journey around the sun. This has the effect of giving Mars a gibbous shape which you’ll see in a ‘scope.
- Polar Ice Caps. Easier to see in Martian winter. The last winter solstice was on Sep 02, 2020. The next one will be July 21, 2022. This year we see the planet’s summer solstice on August 25th.
- Shades of Color. Unless you have a truly enormous telescope you’re unfortunately not going to see detail in Mars’ surface features. However, you should be able to make out smudges of color, where darker and lighter areas of the Martian surface rub against each other.
- Phobos and Deimos. Meaning fear and panic, these are the two small moons of Mars. They are very dim (magnitude 11.3 and 12.4 respectively) putting them beyond the reach of smaller scopes. You’ll need at least an 8” – 10″ aperture with decent seeing conditions to find them.
- Dust Clouds. Mars experiences dust storms and you may be fortunate enough to see one of those through your scope. They don’t run to a schedule, so it’s all in the luck of your timing.
For more details click this link for our dedicated guide to seeing Mars with a telescope.
When Can We See Mars from Earth in 2021?
January: Mars is an evening object best viewed around 7pm this month when it will be at its highest over the southern horizon moving from Pisces to Aries. It’s two-thirds of the way towards the zenith (overhead) and shines at magnitude 0.1. Its disc is small: just below 10 arcseconds across.
February: Mars moves from Aries to Taurus this month, where it stays until late April. The Red Planet is best observed as soon as it’s dark because that is when it is highest in the sky. Find its seven-arcsecond disc 60° above the southwest horizon 90 minutes after sunset.
March: We see the planet sinking slowly towards the Sun this month; it is now only midway between the zenith and western horizon 90 minutes after sunset. Its disc has shrunk further to below 6 arcseconds and it is much dimmer at magnitude 1.1.
April: Now only 35° over the western horizon 90 minutes after sunset, Mars is a tiny 5-arcsecond disc shining at magnitude 1.4, but is still observable until midnight.
May: Mars moved into Gemini at the end of last month, where it remains throughout May. The Martian disc is still shrinking as it heads away from us, but only slowly, causing it to dim further to magnitude -1.6. The decline in viewing opportunity accelerates quickly this month.
June: As Mars moves into Cancer it also moves closer to the Sun. We see it just 16° above the western horizon an hour after sunset. It’s a shadow of its closest approach now, shining at magnitude -1.6 with a disc just 4 arcseconds wide. By the end of the month, it sets two hours after the Sun.
If you’re looking for more detail than this, take a look at the Virtual Astronomy Club. Each month we issue detailed guides for observing Mars, including exactly where to look each day.
July: In practical terms, Mars becomes impossible to see before the middle of the month because it moves too close to the Sun. In the first days of July, you may catch a glimpse of it very low on the western horizon as dusk takes hold.
August: Mars is not observable this month because it is too close to the Sun. It won’t be visible again before December.
September: Mars is not observable this month because it is too close to the Sun.
October: Mars is not observable this month because it is too close to the Sun. It reaches superior conjunction on the eighth of October when it is directly behind the Sun from our perspective.
November: Mars is not observable this month because it is too close to the Sun.
December: Mars reappears in morning skies in the last days of the year. In the last week of December, we’ll be able to glimpse it 9° above the southeast horizon in Ophiuchus an hour before sunrise. Its disc will still be four arcseconds wide and shining at magnitude 1.5.
Is Jupiter Visible Tonight?
The fourth of our five visible planets is the solar system’s giant: Jupiter.
Even though it is much further from us than Mars, the fact it’s well over a thousand times larger than the red planet means Jupiter shines more brightly than it in our skies. At its brightest, Jupiter is the third brightest object in the night sky, beaten only by Venus and the Moon.
So, if you’re wondering ‘can I see Jupiter without a telescope’, you absolutely can! It’s a bright planet and can be found shining in the constellations of Capricornus and Aquarius 2021.
Whilst you can see Jupiter without a telescope, it is a great planet to look at with one. There is so much to see on its surface and you can see the brightest moons of Jupiter too. If you don’t own one yet, take a look at our reviews of the best telescopes.
Even binoculars will show you the famous Galilean moons of Jupiter and a small scope will bring out the different brightnesses of the bands on the planet’s surface, if not the colors themselves.
Where Can You Find Jupiter?
Is Jupiter in the sky tonight? Well, happily, for most of 2021 the answer to that question is… Yes!
However, it leaves evening skies in the first weeks of the year and can’t be seen again until before the Sun rises at the end of February. After that, it stays visible all year long, reaching opposition on August 19th. From then onwards, Jupiter is visible in evening skies to the end of the year. More detail follows below.
If you want to know where to find Jupiter’s moons tonight, then we recommend this simple tool from Sky & Telescope (link opens a new tab). Put in the date and time of your observing and discover where the Galilean moons will be.
Jupiter Seeing Challenges:
- Galilean moons. The four moons closest to Jupiter (from a total of 67 known moons) were discovered by Galileo Galilei over 400 years ago 1610. Outwards from the planet, they are Io, Europa, Ganymede (itself bigger than planet Mercury), and Callisto.
They are easily visible as pinpricks of light on either side of Jupiter when they’re not behind it. They move quickly and this almanac from Sky & Telescope will tell you which ones can be seen on any given day.
- Bands of Color. Jupiter is famous for its gas bands and even a relatively small telescope will show you the main bands as faint shades of grey. Larger scopes will reveal more detail and some color.
- Great Red Spot. This is perhaps Jupiter’s most famous feature, which is why we have a dedicated guide to seeing the Great Red Spot. You’ll need a decent magnification (250x) to see it, and this almanac to make sure you’re looking for it at the right time.
- Moon Transits. Seeing the moons themselves is simple, but can you see them and their shadows cross in front of the planet? With good seeing, optics, and this almanac, you’ll be proud of managing to see one of these events.
For more details click this link for our dedicated guide to seeing Jupiter with a telescope.
When Can We See Jupiter from Earth in 2021?
January: Jupiter can be spied low on the horizon after sunset for the first few days of the month but, by mid-month, the largest planet sets just 40 minutes after the Sun. From this point, it is not possible to see it as it goes around the back of our star. It reaches superior conjunction on the 28th of the month, reappearing at the end of next month before sunrise.
February: Jupiter is not visible for most of the month. Even on the very last day of February, it is a tough target, rising just 4° over the east/southeast horizon forty minutes before sunrise.
March: Viewing improves rapidly now, although we only have a few short minutes to see the planet low on the dawn horizon. By mid-March, Jupiter is 8° above the southeast horizon forty minutes before sunrise. Its disc is 33 arcseconds wide and shines at magnitude -2.0.
April: An hour before sunrise Jupiter is 14° above the southeast horizon, shining at magnitude -2.1.
May: Jupiter has passed into Aquarius and, an hour before sunrise, is 25° above the southeast horizon. The planet itself rises before 3am, providing a good window of viewing. As it moves closer to us, the Jovian disc grows to 38 arcseconds wide and brightens to magnitude -2.3.
June: As the August opposition draws nearer, we see Jupiter’s disc grow again to 42 arcseconds and its brightness to magnitude -2.6. The planet rises before 1am and is highest in the sky as dawn breaks. See it 35° over the south/southeast horizon.
If you’re looking for more detail than this, take a look at the Virtual Astronomy Club. Each month we issue detailed guides for observing Jupiter, including exactly where to look each day.
July: The largest planet in our solar system is now transiting the southern horizon (its highest point in the sky) at 4am, i.e. during the hours of darkness. At that point it will be almost 40° above the horizon, shining at magnitude -2.8, and its disc is 46 arcseconds wide.
August: Jupiter reaches opposition on the 19th, just as it crosses back into Capricornus from Aquarius. On this date, it will be 38° above the southern horizon at 1:30am. The Jovian disc will be 48 arcseconds across and shining at magnitude -2.9.
September: With the opposition behind us, Jupiter becomes an evening object. It reaches its highest point before midnight over the southern horizon. It fades fractionally to magnitude -2.8 as its disc shrinks by just one arcsecond from the peak last month.
October: We’re moving into a great period of evening observation of Jupiter as we hit the last quarter of 2021. The massive planet is highest over the southern horizon around 9:30pm and still has a huge 43-arcsecond disc shining at magnitude -2.6.
November: The highest reach of Jupiter, 36° above the southern horizon, occurs between 6pm and 7pm now. As Jupiter continues to recede from us its disc shrinks to 39 arcseconds and its brightness fades marginally to magnitude -2.4.
December: We finish the year with Jupiter’s transit now happening in daylight hours. This means that the best time to view it this month is an hour after sunset when it will be 34° above the horizon. The planet moves back into Aquarius as we say goodbye to 2021. Jupiter’s disc is 35 arcseconds wide and shining at magnitude -2.2.
Is Saturn Visible Tonight?
Next, we come to the last of the five planets visible from Earth with the naked eye. And, for many, the most spectacular to look at with a telescope.
If you’re wondering “can I see Saturn without a telescope?” you absolutely can! At its brightest Saturn’s light outshines every star – only the moon and four closer planets beat it, so it’s easy to pick out.
For many astronomers, nothing beats their first view of Saturn and its awe-inspiring rings through the eyepiece of a telescope. It’s a pleasing and surreal sight that keeps many of us coming back to the ringed planet time and again.
Where Can You Find Saturn?
Like Jupiter, Saturn is a gas giant and even with its truly enormous distance from us it shines brightly in the sky and is easy to pick out with the naked eye.
Saturn’s distance from the Sun means it takes a leisurely 30 years to orbit the sun so, throughout 2021, it doesn’t move much against the background of stars. The planet spends the whole year in the constellation of Capricornus.
Much like Jupiter, Saturn has poor visibility for the first quarter of 2021. It improves as a morning object from March, reaching opposition (its closest approach to Earth) on October 2nd. After that, Saturn is an evening object visible for the rest of the year.
Saturn Seeing Challenges:
- Saturn’s rings. Of course, this is where we start! In 2018 the rings appeared wider (more angled towards Earth) than since 2003. In 2021 the angle is a little flatter but they are still very enjoyable to see. Binoculars won’t show them, but even the most modest telescope will reveal their glory.
- Individual rings. With a larger telescope and more magnification, it’s a good challenge to break the rings down into their component parts: rings A, B, C, and D, and the Cassini Division.
- Titan. Saturn’s largest moon (which, like Ganymede, is also larger than Mercury) shines at magnitude 8.3 and is visible with a 4” scope.
It orbits quite a distance from the planet but is relatively easy to find if you look at the right time.
There are another 61 moons around Saturn, but none even close to the size of Titan. However, if you’re fortunate enough to have an 8” scope, you could try spotting the next four largest moons, which are Enceladus, Dione, Tethys, and Rhea. Use this almanac to help you find them.
When Can We See Saturn from Earth in 2021?
January: Saturn can be glimpsed for the first few days of 2021 a few degrees above the southwest horizon as dusk gathers. However, it reaches superior conjunction on Jan 23, which is when it is directly behind the Sun. Consequently, it is not visible from around the 8th of this month.
February: If you have a good, clear view of the southeast horizon, you can catch sight of Saturn forty minutes before sunrise just a few degrees above the horizon.
March: An hour before sunrise, Saturn is perched 10° above the southeast horizon. Its disc is 15 arcseconds wide and it shines at magnitude 0.7.
April: Saturn rises before 4am and is best seen an hour before sunrise when the sky is dark. Find it 19° above the southeast horizon, slightly higher, and to the south of brighter Jupiter. Saturn’s disc and magnitude are practically unchanged from last month.
May: The ringed planet’s magnitude stays at 0.7 even as its disc increases to 17 arcseconds. It reaches the highest point in the sky after sunrise, so is still best viewed above the southeast horizon an hour before it.
June: As opposition comes closer, we’re in a position to see Saturn at its highest point before sunrise. At mid-month, the ringed planet crosses the south horizon before 5am at an angular height of 33°.
If you’re looking for more detail than this, take a look at the Virtual Astronomy Club. Each month we issue detailed guides for observing Saturn, including exactly where to look each day.
July: Transit happens before 3am in the middle of July, which is the best time to view the planet. However, it rises before 10pm so can be observed in the evening too – ideal for most of us. Saturn is moving closer so its disc has grown to 18 arcseconds and has brightened to magnitude 0.3.
August: Opposition is reached on the second day of the month. Transit is a little after 1am and the size and brightness reach their maximums of 18.6 arcseconds and 0.2 respectively.
September: With opposition behind us, Saturn moves firmly into evening observation territory. The planet rises before sunset and reached 32° above the southern horizon – transit – a little after 10pm. The disc and brightness are little changed from their August peaks.
October: In this last quarter of 2021, Saturn begins to noticeably fade. On the positive side, we can now observe it high over the southern horizon at 8pm. The disc of Saturn shrinks to 17 arcseconds and brightness fades to magnitude 0.5.
November: Saturn’s transit occurs after sunset now, so the best time to see it is as dusk turns to night. The disc is 16 arcseconds wide and brightness has faded again to magnitude 0.7.
December: Saturn finishes the year 22° above the southwest horizon an hour after sunset and sets itself before 9pm. The size and brightness of the disc are little changed as the planet heads for conjunction in February 2022.
Can I See Uranus and Neptune Tonight?
We touched on them briefly in the introduction. Uranus and Neptune are the last two planets in the solar system.
We’ve not covered them in detail as they are a much harder spot than the other five, but they may be a challenge you want to take on as you become more proficient at looking around the sky with your telescope.
It can be hard to know if you’ve found what you’re looking for, but they both shine with a blue/green light and, of course, they move over successive nights with respect to the background stars.
The four of the five visible planets put on spectacular shows at various points in 2021. Only Mars, in its fallow year, remains too small and faint for high-quality observation.
Each planet offers its own unique challenges from simple to moderately difficult.
Make a reminder to look for Mercury and Venus when they are at greatest elongation. For Jupiter and Saturn, you’ll see the most detail when they are at opposition. Mars does not reach opposition in 2021.
2021 Opposition Dates for the Planets
- Mars – No opposition in 2021
- Jupiter – August 19th
- Saturn – August 04th
- Uranus – November 04th
- Neptune – September 14th
These are some useful resources to help you further with your planet observation.
- The Virtual Astronomy Club
- Sky & Telescope Magazine subscription (see our review article)
- NASA’s planetary factsheets
- Maps of planets against constellation background
Calendar research, thanks to Tanya C. Forde