What Planets Are Visible Tonight?

What planets are visible tonight?

Some of the best views in astronomy actually come from the planets and not stars. So, while it’s understandable that you probably want to view the faraway stars and nebulae, don’t forget that the planets of our solar system—that are relatively close—can be great objects to find and observe.

All of the 7 planets (not counting our Earth) in our solar system are technically visible depending on your location, however, there are five special planets that we can observe with just the naked eye: Mercury, Venus, Mars, Jupiter, Saturn. In January, the four bright planets—Venus, Mars, Jupiter, and Saturn—are particularly visible to the naked eye, offering unique features and exciting viewing opportunities.

Uranus and Neptune, the two outer planets, can be barely visible depending on your location. However, even when they are visible, they’ll look identical to stars. You’d need a good telescope or a good pair of binoculars to properly observe these outer planets.

Understanding the Night Sky

The night sky is a vast and fascinating expanse that has captivated human imagination for centuries. To fully appreciate its beauty and complexity, it’s essential to understand the various celestial bodies that inhabit it. In this section, we’ll delve into the world of moon phases, planetary visibility, and planetary alignments.

Moon Phases and Planetary Visibility

The moon orbits the Earth in approximately 29.5 days, completing a cycle of eight distinct phases: new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, and waning crescent. Each phase offers a unique viewing experience, with the full moon being the brightest and most visible. The full moon illuminates the night sky, making it easier to spot planets and other celestial objects.

Planetary visibility is influenced by the Earth’s rotation and its orbit around the sun. The five planets visible to the naked eye – Mercury, Venus, Mars, Jupiter, and Saturn – appear in the night sky at different times throughout the year. Their visibility is determined by their proximity to the sun and their position in their orbits. For instance, Venus often shines brightly in the evening sky or during the bright morning twilight, while Jupiter can be seen as a bright star-like object when it is high in the sky.

Planetary Alignments and Conjunctions

Planetary alignments occur when two or more planets appear close to each other in the night sky. These events are often spectacular and offer a rare opportunity to observe multiple planets simultaneously.

Conjunctions, on the other hand, occur when two or more celestial bodies appear close to each other in the sky. These events can be particularly striking when involving bright planets like Jupiter and Venus. For example, a conjunction of Venus and Jupiter can create a dazzling display, appearing as a single, exceptionally bright star.

Planet Observation: Why Planets Have Different Observing Times

Unlike stars, planets don’t follow a simple cycle and different planets in our solar system have different cycles. When the planets appear is dictated by their own rotational period and how planets orbit the sun. Mercury, for example, has a 88 days rotational period, but Saturn needs 29 years to fully orbit the Sun.

So, every January, for example, these planets can have different positions in relation to the Sun and the Earth, and so some planets might be observable in January 2020, but won’t be available in January 2021.

With that being said, if you want to observe stars, make sure you are looking at the right calendar.

Planet Observations: The Best Time to Observe Bright Planets

https://upload.wikimedia.org/wikipedia/commons/f/f6/Positional_astronomy.svg

The above image will explain the best time to see the different planets, but we have to delve further before we can explain it properly. Observing from clear, dark skies, especially away from bright city lights, enhances the experience of watching planets.

As mentioned, we are going to mainly focus on the five ‘visible’ planets, and we can further divide these planets into two groups:

1. Inferior planets: planets that lie inside our Earth’s orbit and are closer to the sun. Mercury and Venus belong to this category.
2. Superior planets: planets that lie outside our Earth’s orbit and are further from the sun. Mars, Jupiter, and Saturn belong here.

The Best Time To See Inferior Planets

Since, as mentioned, Mercury and Venus performed their rotations inside the path of the Earth’s orbit, there are several things we must consider:

• Mercury and Venus orbit faster than the earth, they do their rotation in 88 days and 225 days respectively. So, they change position very quickly and you have smaller windows to observe them.
• Because we can see parts of the planet facing away from the sun, and so they have phases, called the planetary phase, just like the moon. So, we can only see them in full at certain times.

In general, the best time to see the inferior planets is during their western and eastern greatest elongations, as you can see in the image above. The best times to observe Mercury and Venus are when they rise and set during their greatest elongations.

On the other hand, the worst time to observe these inferior planets is when they are in conjunction. In the image above we can see that there are inferior conjunction and superior conjunction. It’s important to note that they don’t mean conjunctions for inferior and superior planets, respectively, instead:

• Superior conjunctions are conjunctions that happen when the planet is on the opposite side of the sun in comparison with the earth’s position
• Inferior conjunctions, on the other hand, are when the planet is positioned between the earth and the sun

The inferior planets can’t be observed when they are at (and near) conjunctions since they are going to be obscured by the sun’s glare.

However, a very rare occasion is when the planet is on the same plane as the earth and the sun, and inferior conjunction happens. In this rare case, we can see a mesmerizing view of the planet (Venus and Mercury) to pass in front of the sun.

Sadly this occasion called Transit of Venus is sill 97 years in the future, and for Mercury, we still need to wait until 2032.

The Best Time To See Superior Planets

Mars, Jupiter, and Saturn (and also Uranus and Neptune) make their rotations outside the earth’s orbit. So, there have different characteristics compared to Mercury and Venus:

• As expected, they take longer to complete their rotation period, and so they move slowly across the celestial sphere. That is, parallax-wise, these planets only move a short distance compared to the stars in their background.
• Since the earth is inside the orbit, we can only see the side facing the sun. So, they don’t have phases and we will always see them in full.

The best time to see these superior planets is at opposition, not elongation. If we see again at the image above, the superior planets never pass between the Earth and the sun. So, at the opposition, we sit directly between the planet and the sun. So, they won’t be obstructed by the sun’s glare.

The planet during their opposition is visible all night long and is transiting (highest positioned) around midnight. The visibility of superior planets can vary based on geographical location, particularly for viewers situated at mid northern latitudes.

What Visible Planets are Visible Tonight?

As darkness falls, the visibility of planets becomes clearer. If you want to check what planets are visible tonight, then you can check the two tables below. These tables show which of the five planets can be seen tonight in each month of 2020 and 2021.

Before we explain them month-by-month, here are a bit of explanations for the terms we use in the tables:

• -: not observable, mainly because the planet is too close to the sun.

• Dusk: the planet is visible in the western sky after sunset (around an hour or so). For Venus and Mercury, a bold dusk indicates the month when greatest eastern elongation (the best time to view them) takes place. Since elongation for mercury only happens for a very short time, dusk (early) indicates that elongation happens at the early part of the month, dusk (middle) indicates the middle part of the said month, and dusk (later) indicates the later part of the month.

• Dawn : the planet is visible in the eastern sky before sunrise (around an hour or so). For Venus and Mercury, a bold dusk indicates the month when greatest western elongation (the best time to view them) takes place. Since elongation for mercury only happens for a very short time, dawn (early) indicates that elongation happens at the early part of the month, dawn (middle) indicates the middle part of the said month, and dawn(later) indicates the later part of the month.

• Morn: the planet is best seen in the Morning sky, after midnight and before dawn. The planet reaches its highest possible point in the celestial sphere when it crosses the meridian (due North in the Southern hemisphere, due South in the Northern hemisphere) during the Morning.

• Eve: the planet is best seen in the evening sky, after dusk but before midnight. The planet reaches its highest possible point in the celestial sphere when it crosses the meridian (due North in the Southern hemisphere, due South in the Northern hemisphere) during the evening or late afternoon.

• ALL: the planet can be seen all night long from dusk to dawn, at least for most of the night. The planet reaches the highest point in the celestial sphere within an hour before or after midnight. For superior planets, ALL indicates that the planet’s opposition occurs in this month.

Keep in mind that even at their best time of viewing, the planets may not be visible depending on your latitude, weather for the night, the planet’s current magnitude, and various factors affecting the sky’s condition.

Month-by-Month Details: Planets Visible in the Night Sky Today

Additional Resources

Sky Dome Maps and Heliocentric Solar System

Sky dome maps are a valuable tool for stargazers, providing a visual representation of the night sky and the position of celestial bodies. These maps can be used to plan stargazing sessions, identify constellations, and locate planets and deep sky objects. By using a sky dome map, you can easily find the best times and locations to observe the brightest stars and planets.

A heliocentric solar system is a model that places the sun at the center of our solar system, with the planets orbiting around it. This model is essential for understanding the motion of the planets and their relative positions in the night sky. By studying the heliocentric solar system, astronomers can gain insights into the behavior of celestial bodies and make predictions about future alignments and conjunctions. This knowledge can enhance your stargazing experience, allowing you to anticipate and observe spectacular events in the night sky.

I hope this helps! Let me know if you need any further assistance.

Summary

We hope this guide can help you make the most of your 2020 stargazing and planet observation plan. The five visible planets, and also Uranus and Neptune all put out unique and spectacular views at various points in 2020.

Obviously, each offers its own challenges, so it’s best to prepare ahead and get the best astronomy equipment before you set to observe the planets.