- 1 2021 Astronomer’s Guide to the Night Sky
- 2 Phases of the Moon
- 3 Using a finderscope
- 4 Useful resources
People have been stargazing for millennia, using the sky as a sort of map for navigation, creating stories and mythologies about the stars, and wondering what it would be like to travel the galaxy. There’s something so fundamental and human about the sense of awe and wonder that planets, stars, moons, and nebulae inspire in us.
If you’re hoping to learn more about astronomy or astrophotography in 2021, this guide will help you get started.
So, how do you actually do astronomy? How do you find and observe celestial bodies?
It comes down to three big questions: What, when, and where.
- What should you look for? What do you want to see? What is even visible, given the technology you have, the weather, and the time of year. Which brings us to…
- When should you look for Object X or Planet Z? Many celestial bodies are visible on some nights and not others. Others appear at their best during a particular time frame. Knowing when to look for something is very important. And finally…
- Where should you look? It’s one thing to know, intellectually, that Mars is supposed to be bright tonight, but that knowledge doesn’t amount to much if you don’t know where to point your telescope.
This guide breaks down the What, When, and Where for you.
It explains what is visible in the night sky in 2021 and helps you figure out how to locate celestial bodies.
First, I’ll point you to some of the more popular astronomy resources that can help acquaint you with the night sky and keep you in the know about what’s visible.
Then, I give a list of highlights for 2021: Eclipses, meteor showers, conjunctions, transits, and so on. These events only happen on specific dates, so plan ahead to see them.
Next, I discuss each planet and its visibility throughout the year. When is Jupiter visible in the morning sky, and when in the evening? Which direction should you look to find Mercury? When will Venus be completely invisible? I cover all that in this section (and I also give some love to Pluto at the end).
In the final sections, I discuss the phases of the Moon and how that affects your stargazing, and I briefly go over finderscopes, a tool that will help you locate things if you’re using a telescope.
2021 is already well underway, so let’s get started!
Note: What you can see in the night sky often depends on your own location on planet Earth. Where possible throughout this guide, I specify where you need to be to see various events, eclipses, etc. Dates and times also vary depending on your time zone, so make sure to double-check times for any event you’re hoping to observe.
But first, make sure you have the right telescope…
What Are The Best Telescopes for Viewing Planets and Galaxies?
2021 Astronomer’s Guide to the Night Sky
Grab your calendar: Here are some of the best things to see in the sky in 2021.
May 26, total lunar eclipse: This eclipse will be visible in Australia, parts of the western US, western South America, and South-East Asia. This will be a Blood Super Moon event, as the full moon will be close to the earth.
June 10, annular solar eclipse: In an annular solar eclipse, the Moon travels in between the Earth and Sun but does not completely block the Sun. Instead, it creates a dramatic image in which the Sun shines like a halo around the edges of the dark Moon. The path of this eclipse will be visible from parts of Russia, northern Canada, and Greenland. If the weather allows, folks in the US, Europe, and Northern Asia will be able to see a partial eclipse.
November 18-19, partial lunar eclipse: Look out for this eclipse if you live in North and South America, Australia, and parts of Europe and Asia.
December 4: total solar eclipse: Look out for a view of the total phase of this eclipse if you live in Antarctica. A partial solar eclipse can be viewed from parts of southern Africa, including South Africa and Namibia.
April 16-30, Lyrids: This annual meteor shower will run for about a couple of weeks from April 16 to 30, with 21 and 22 April supplying the best opportunities. At its apex, it may produce around 18 meteors per hour. Head to a dark place after midnight to try to spot meteors. This one is best observed from the Northern Hemisphere.
April 19 – May 28, Eta Aquariids: This incredible meteor shower (around 60 meteors per hour at the peak) will appear to its best advantage in the Southern Hemisphere, though it should also be visible in the North. When to head outside and watch? The night of May 4-5 is expected to be optimal, though it should be active from April 19 until May 28.
July 12 – August 23, Southern Delta Aquariids: This shower is another good one to catch if you’re in the Southern Hemisphere. It produces meteors each year from mid-July to mid-August.
July 17 – August 26, Perseids: The Perseids constitute one of the best-known and most enjoyable meteor showers in the Northern Hemisphere. The night of August 11-12 is projected to be the peak in 2021, but you can also try to spot meteors in the days before and after.
October 2 – November 7, Orionids: This is a medium to strong meteor shower that has been known to produce impressive fireballs. Try your luck in the pre-dawn hours of October 21-22.
December 4-17, Geminids: This awesome annual shower can produce up to 120 meteors per hour! Best seen from the Northern Hemisphere, the Geminids are 100% worth staying up late to see. In 2021, this shower is expected to peak the night of December 13-14, which is close to a new moon—that means dark skies and excellent viewing conditions. Meteors should be visible all night long and at their best around 2 am.
December 17-26, Ursids: Meteors will appear in the Northern Hemisphere between December 17 and 26, reaching their peak around December 22. The Ursids aren’t as flashy and dramatic as the Geminids just a week before, but I’m fond of them nonetheless.
This is definitely not an exhaustive list! For a super detailed (and somewhat technical) guide to 2021 meteor showers, check out the International Meteor Organization’s 2021 Meteor Shower Calendar.
Planetary events (e.g. conjunctions, oppositions)
March 29: Conjunction of Mercury and Neptune. You’ll need to view this phenomenon through a pair of binoculars, as the planetary pair will be too widely separated to see through the view of a telescope.
May 29: Conjunction of Venus and Mercury
July 13: Conjunction of Venus and Mars
July 18: Pluto at opposition
August 19: Conjunction of Mercury and Mars
August 20: Jupiter at opposition
September 14: Neptune at opposition
November 4: Uranus at opposition
December 13 and 22: Conjunction of Venus and Pluto
December 29: Conjunction of Venus and Mercury
December 30: Conjunction of Mercury and Pluto
This is just a sample of the many exciting astronomical events that you can observe this year. For a longer list of 2021 astronomical events, check out this calendar.
In the next section, I’ll discuss each planet, one by one, and offer some tips on when and how to view them at their best.
If you look at the night sky tonight you might not realize what you are looking at. It seems like there are so many planets and stars in the solar system let alone the ones circling around the sun that they all look the same from so far away.
Stars are the brightest objects in our solar system, but that doesn’t mean that you won’t be able to spot Mercury, Venus, Mars, Jupiter, Saturn, Uranus, or Neptune through a telescope. The brightest planets are visible with the naked eye, but if you are just starting out on your planet spotting adventures make sure you look through a telescope so that you are sure of what you are seeing.
Which Planets are Visible Now?
Generally speaking, there are five “visible” planets in our solar system. Of course, any planet is technically visible depending on where you’re standing, but these five can be seen with just the naked eye. They are:
And Honorable Mention goes to Earth, which is certainly visible but not really the point here.
What about the so-called outer planets, Uranus and Neptune? At times, they might be just visible with the naked eye, but they’ll look identical to stars. To appreciate these planets, you need a good pair of binoculars or a telescope.
Now, I’ll go through each planet in turn and explain when you’ll have the best observing conditions.
If you want a quick reference for later, check out this chart, which indicates, at a glance, whether a particular planet is visible on a given morning or night.
Bear in mind, however, that charts like this one are broken down by month—so, what if Planet X is visible for half of the month? Or only a few days? In those cases, you’ll need to consult a more detailed guide for precise dates!
Mercury is a relatively small planet, but it’s still often visible. What does it look like? With the naked eye, it appears similar to a bright star with a yellowish or earthy color.
Write the following dates on your calendar for viewing Mercury:
- January 22: optimal chances for viewing after sunset.
- March 6: before sunrise
- May 17th: after sunset
- July 4: before sunrise
- September 13: after sunset
- October 25: early morning before sunrise
How to find Mercury
Mercury is small, speedy, and close to the Sun, and it can be very tricky to locate. For one thing, Mercury tends to appear low on the horizon. So if you’re surrounded by buildings, your view of Mercury will likely be blocked.
Your first step is to get outside and up a hill, ideally in a nice field without tons of trees to block your views of the horizon.
Another complication: Mercury does not remain visible all night long, so you don’t have tons of time to look for it. It is either visible just before sunrise or just after sunset. You should have about an hour-long window either pre-dawn or post-dusk in which to find Mercury.
This adds the challenge of looking for Mercury in slightly brighter skies rather than in total darkness. But with some luck and preparation, you should be able to locate it.
Where should you look? Remember that Mercury is close to the Sun. Let’s say you’re looking for Mercury in late February when it will appear in the evening (post-dusk) sky. The Sun sets in the west, and Mercury will appear in the west as well.
What if you’re searching for Mercury in late November when it appears in the morning (pre-dawn) sky? The Sun rises in the east, and Mercury will appear in the east too.
Pay attention to the dates of greatest elongation. I’ve marked them in the list up above, but here they are again all together:
- January 24: greatest eastern elongation
- March 6: greatest western elongation
- May 17: greatest eastern elongation
- July 4: greatest western elongation
- September 14: greatest eastern elongation
- October 25: greatest western elongation
These dates give you the best chances for viewing Mercury.
For even more detail and guidance, check out the Mercury Chaser’s Calculator, which lets you enter any year to find out when Mercury’s maximum elongations will be (or were).
Finally, a warning: Take care during your search for Mercury—due to its close proximity to the Sun, there’s a risk of accidentally looking directly at the Sun instead, which is dangerous and inadvisable.
Named for the goddess of love, Venus is about the same size as the earth, but it’s otherwise incredibly different and distinctive. It has a volcanic landscape and is covered in acidic clouds. The planet’s surface reaches temperatures of 900oF (465oC)—not exactly hospitable to human life!
Venus shines brightly in the sky and can be stunning to observe. Keep an eye out for it on the following dates:
- May 12: approximately half an hour after sunset
- July 13
- October 28 to 29
- November 19
- December 7. Venus will be visible throughout the month of December and will take on a crescent phase, becoming progressively larger and thinner.
How to find Venus
Venus is one of the brighter objects visible in the sky, which should help you locate it even without the assistance of a telescope. In fact, you can even spot Venus during the day.
Similar to Mercury, it tends to appear either in the morning (before sunrise) or evening (after sunset) rather than throughout the night or at midnight.
You have a slightly longer window of time in which to find Venus, however, since it is further from the Sun. The benefit of this: You can search for Venus while the sky is dark.
Also like Mercury, Venus tends to stay quite close to the horizon line. When it appears in the morning, it can be found in the east (like the rising Sun); when it appears in the evening, it is found in the west (like the setting Sun).
Finally, Venus appears to have phases like the Moon. Once you find it, you can take note of the planet’s current phase.
Mars is famous for its rugged reddish landscape which gains its color from iron minerals in the soil. It’s also famous for the human fascination with someday colonizing it, encouraged by films like The Martian.
2018 was a superb year for viewing Mars, and 2021 should also be a great year for the Red Planet.
- January 19-21, when Mars will appear near the moon.
- March, with the biggest event on the 3rd of March, when Mars and the Pleiades star cluster being in close conjunction.
Don’t miss seeing Mars at solar conjunction on the 8th of October.
How to find Mars
If you’re interested in finding Mars in 2021, I strongly recommend this description of its movements throughout the year.
You can locate Mars by researching where it is located in relation to constellations. Use a star chart to orient yourself in the night sky, learn where constellations are, and use them as landmarks to find Mars.
Mars will move out of the constellation Taurus on the 24th of April and move into the Gemini constellation.
Consult this chart to trace Mars’ movements over the second half of 2021.
The largest planet in our solar system, Jupiter and its many moons have been impressing astronomers since Antiquity. Its famous Red Spot may look tranquil from a distance, but it is in fact a massive storm that has lasted for over a century.
Observe this gas giant for yourself on these dates in 2021:
- January 1-9 in the evening sky. From 17 February to 19 August you’ll be able to view it in the morning, and again in the evening from the 20th of August to the 31st of December.
- The planet will be at its brightest from the 8th of August till the 2nd of September when it’s at opposition to the sun.
- Keep an eye out just before sunrise on the morning of the 5th of March when Jupiter will be visible just the right of Mercury. You’ll want to use binoculars for this.
Jupiter is one of the brightest objects in the night sky, ranking just behind the Moon and Venus. You can see it with the naked eye, though you’ll of course have better views through binoculars or a telescope.
Check out Naked Eye Planets for a super-detailed description of when and where Jupiter will be visible in the night sky during 2021.
The best views of Jupiter will occur on the 8th of August when it reaches opposition to the Sun. This means that it is relatively bright and close to the Earth, as well as visible all night.
If you have a telescope, challenge yourself to find not only the planet itself but also its details and features. Can you find its largest moons? Its gas bands? Its famous great Red Spot?
This ringed planet has inspired countless people to fall in love with astronomy. Did you know that Saturn is losing its rings though? Don’t worry: You still have about 100 million years to see and appreciate them!
Here’s when to view Saturn in 2021:
- January 1 – January 6, in the evening sky.
- February 10 – August 1, in the morning sky.
- August 2 – December 31, in the evenings.
- Saturn will be at its brightest between August 1 to August 4. Saturn is at opposition to the Sun on the 2nd of August.
How to find Saturn
For most months of 2021, there is at least one night when you can use the Moon as your anchor to locate Saturn, which will appear nearby. Since the Moon is so easy to spot, it serves as a very useful guide toward Saturn. These circumstances will occur on the nights of:
- February 9-10
- March 9-10
- April 5-6
- May 30-31
- June 26-27
- July 24-25
- August 20-21
- September 16-17
- October 13-14
- November 10-11
- December 7-8
Note that the relative positions of the Moon and Saturn, as well as the precise timing of this occurrence, will depend somewhat on your own location on Earth.
Uranus is an ice giant, meaning that it comprises a rocky core covered by an “icy” mass of water, ammonia, and methane. Like Saturn, Uranus has rings, and it also has 27 moons (that we know of!). Uranus is also quite large, around four times wider than Earth.
Despite its relatively large size, Uranus is very difficult to see with the naked eye, and without technological help, it pretty much just looks like a star. I highly recommend getting a good telescope or pair of binoculars to see it closer-up and in more detail.
Aries will spend the entire 2021 in the constellation of Aries the Ram. Look for Uranus on the following dates:
- January 1 to April 12, in the evening sky.
- May 16 to November 3, in the morning sky.
- November 4 to December 31, in the evening sky.
- Brightest from August 28 until the end of the year.
How to find Uranus
One strategy for finding Uranus is to wait until it appears in conjunction with other, brighter planets.
In 2021, that means January 21, when it appears with Mars.
Like Uranus, Neptune is an ice giant with a gassy atmosphere of molecular hydrogen, atomic helium, and methane. What sets Neptune apart? For one thing, it’s the windiest planet in our solar system. These high winds propel frozen methane clouds across Neptune at 1200+ miles per hour (2000+ kilometers per hour).
You’ll need a telescope or a solid pair of binoculars to observe Neptune—and in my experience, it’s definitely worth it! In 2021, look for Neptune in the constellation Aquarius, where it will spend the entire year.
- January 1 to February 23, in the evening sky.
- March 27 to September 13, in the morning sky.
- September 14 to December 31, in the evening sky.
- As you can see, Neptune will be visible for much of 2021, though it will be brightest between July 19 and November 8.
- 10 March – Solar conjunction
- 14 September – Neptune at opposition
How to find Neptune
Then, use this finder chart (or this one, for the Southern Hemisphere) for more specific help with locating Neptune in 2021. You can also find printable finder charts for Neptune here. This year, Neptune will appear in the northeastern part of Aquarius.
Neptune will be in conjunction with Venus on January 27, with Mercury on April 3, and with Mars on June 12; the January 27 conjunction is best seen from the Northern Hemisphere, while the latter two conjunctions are both best seen from the Southern Hemisphere. You’ll be able to use the brighter planets Venus, Mercury, and Mars to help you locate Neptune nearby.
What about Pluto?
Pluto’s status as a planet may be up for debate, but regardless of how it’s classified, it’s still a pretty fascinating object. It’s an icy world located in the Kuiper Belt and has five known moons.
Pluto is too tiny to see with the naked eye. You’ll need a fairly powerful telescope and some dark skies to get a view of it.
Pluto will be at opposition on July 18, 2021, which is, depending on weather conditions, the best date for observing.
Phases of the Moon
I tend to keep track of when the next New Moon will occur. It’s important information that helps me plan some of my stargazing. So, why pay attention to when the New Moon is? Doesn’t that just mean that you can’t see the Moon in the night sky at all?
Yes, and that’s the point. The night of a New Moon (or the nights just before/after) is an excellent time to try observing dim, deep-sky objects such as star clusters and galaxies.
Without the presence of moonlight, the sky is darker, and you have the chance to spot faint objects. So if you hope to view dim, distant galaxies or nebulae, you’ll need to know the date of the next New Moon, so you can observe without any interfering moonlight.
Excess moonlight can put a damper on some viewing opportunities. In 2019, for instance, both the Perseid and Geminid meteor showers hit their peak shortly before or after a Full Moon, which meant that they weren’t as spectacular as they could have been.
The Perseids might be washed out by a bit of moonlight again this year, but the Geminids should be in fine form, as in 2021 they occur close to a New Moon, so the skies will be dark.
On the other hand, the Moon is awesome in its own right! many astronomers enjoy observing the Moon and are hoping to catch it when it’s full. You may also be interested in viewing lunar eclipses or using the bright Moon to locate harder-to-find objects such as Saturn.
So, each phase of the Moon has its advantages and disadvantages, and it all depends on your personal goals. In any case, you should have a basic awareness of the phases of the Moon.
In 2021, the New Moon will occur on the following dates:
- 12 January
- 11 February
- 13 March
- 11 April
- 11 May
- 10 June
- 9 July
- 8 August
- 6 September
- 6 October
- 4 November
- 4 December
You can use websites like Moon Giant to keep track of the phases of the Moon. Moon Giant also provides Moon calendars, lets you virtually explore the surface of the Moon, and has a gallery of vintage NASA pictures.
Using a finderscope
You can see a lot with just your eyes or with a good pair of binoculars. However, planets such as Neptune or Uranus are best viewed with a telescope.
Your telescope probably comes with some sort of finderscope, which helps you locate specific objects in the night sky.
Finderscopes have a wider field of vision; they show more of the night sky (at a lower magnification) than your telescope. This wider view helps you find things more easily. Of course, you still need to have a general idea of where to look.
Center your finderscope on your target. If your finderscope is properly aligned, then this target should show up in your telescope’s eyepiece.
If you’re having trouble with your finderscope, there are numerous video tutorials available to help you troubleshoot. Or, if you belong to an astronomy club, you can ask for help from more experienced members.
There are some fantastic online resources that can save you time and jumpstart your astronomy education. Here are a few of my favorite tools for finding out what’s visible, when, and where to find it:
- Hobby Help’s Beginner Guide to Astronomy
If you’re completely new to stargazing, I recommend starting here. This guide walks you through everything from choosing good stargazing locations to figuring out your new telescope.
This site contains a wealth of information on the night sky. One of its best features is “Objects in your sky: sky diagram.” It detects your location (or you can input whatever location, date, and time you want) and tells you what’s up in the sky on that date, in that place.
So, for instance, it might tell you that in your current location, Jupiter will be visible in the dawn sky at 4:24 am, rising to 20o above the southeastern horizon before fading from view as the sun rises at 6:56 am.
This program will even tell you about galaxies, clusters, comets, and asteroids in addition to the Moon and planets.
Also head to this page, which runs down the list of planet visibility from your location on a given date.
The EarthSky website as a whole contains seemingly endless information—it’s easy to get lost down the rabbit hole!
For our purposes, their section on “Tonight” is a great way to stay up-to-date on what’s visible. You can click through week by week to see upcoming highlights like meteor showers or conjunctions.
- Stellarium (online planetarium)
This online planetarium program shows you a realistic sky with prominent objects labeled (such as the Moon, the planets, and stars such as Deneb, Vega, Pollux, and Betelgeuse). It helps you get acquainted with the sky and the positions of the constellations.
Plus, this virtual sky corresponds with the sky in your particular location—either use auto-location or input a location. You can use Stellarium’s online planetarium to check on what’s visible and then step outside to see the same sky in real life.
Stellarium also provides a list of what planets are visible on a given night. I’ve just checked it for my location tonight: The results? Mercury, Venus, Mars, Jupiter, and Saturn are all visible tonight within specific timeframes.
You can also subscribe to Astronomy magazine, which runs a “Sky this Month” column.
I hope this guide helps you make the most of your 2021 stargazing! The night sky is set to put on a fabulous show this year, and with a little planning, you can watch. Try your hand at finding the planets, get your friends together to view an eclipse, or chill out in a camp chair as you watch a meteor shower. What are you most looking forward to observing this year?
Q: Which planets are visible now?
A: Mercury, Venus, Mars, Jupiter, and Saturn are visible now.
Q: How many planets are there in our solar system?
A: There are eight planets in our solar system.
Q: Which of the eight planets is closest to the sun?
A: Mercury is the closest of the eight planets in our solar system to the sun.
Q: Which of the planets in our solar system is the coldest?
A: Neptune is the coldest planet. The further away from the sun, the planets are, the colder they are.
Q: If we didn’t live on Earth, on which planet could we survive?
A: Scientists believe that Humans could survive on Mars for many reasons. Here are the main reasons why Mars is the most habitable planet:
- Its gravity is 38% that of Earth
- it s temperatures are not extreme
- Plenty of sunlight reaches Mars
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