CONCEPTS (Star Walk2)
What Is the Ecliptic: The Sun's Path In the Sky
Have you ever noticed a yellow dotted line stretching across the sky in stargazing apps like Star Walk 2 or Sky Tonight? That's the ecliptic – probably the most significant celestial reference line. In this article, we'll explore what the ecliptic is, why it’s so important, and how it relates to the zodiac constellations, planetary alignments, eclipses, and other beautiful celestial events.
Contents
What is the ecliptic?
The ecliptic is an astronomical term that reflects the Earth’s movement around the Sun and is observed as an imaginary circle on the celestial sphere and as a plane. Let's figure out what this term means.
The Earth’s orbital plane
As we know from school, the Earth revolves around the Sun, and it takes a year to complete one rotation. The path our planet follows around the Sun through the year is the Earth’s orbit. The plane containing the Earth’s orbit is called the Earth’s orbital plane.
The Earth’s orbital plane intersects the celestial sphere – an imaginary sphere centered on the Earth, representing the appearance of the sky from our planet. The celestial sphere is like a globe with stars, planets, and other celestial objects drawn on it. And the ecliptic is the circle at which the Earth’s orbital plane crosses the celestial sphere. In its turn, the plane containing the ecliptic is called the plane of the ecliptic – it coincides with the Earth’s orbital plane.
The apparent path of the Sun on the celestial sphere
As the Earth orbits the Sun, our star moves along the ecliptic on the celestial sphere. The Sun slowly changes its position in the sky throughout the year, shifting a little less than 1° per day. It appears higher in summer and lower in winter, returning to its original position every year. So, the ecliptic also represents the apparent path of the Sun on the celestial sphere throughout the year.
What objects can you find near the ecliptic?
Most of the Solar System bodies lie close to the ecliptic plane. This means that they orbit the Sun in roughly the same plane as the Earth.
Our Solar System may be generally perceived as a flat disk, and the reason for this is the way it was formed. Scientists believe that billions of years ago, the dust and gas surrounding our Sun were pulled into a disk by gravity; all of today's planets and smaller objects formed out of this disk and remained more or less in the same plane.
Solar System planets
The Solar System planets lie very close to the ecliptic plane, but they are not crossed by it. The orbits of the planets tilt from the ecliptic plane by a few degrees at most. Mercury has the largest tilt (7°), and the other planets range from 0.8° to 3.2°.
Since the planets travel near the path of the ecliptic, they often meet each other in the sky, creating amazing celestial events. When two Solar System planets pass within a few degrees from each other in the sky, it’s called a close approach. When at least three planets appear close together in a small sky sector, it’s called a planetary alignment.
Do you want to explore the Solar System planets even more closely? Take our quiz and try to guess the planets by their features!
The Moon
The orbit of the Earth's Moon tilts 5.1° from the ecliptic plane. The Moon’s orbit crosses the ecliptic plane at two points: ascending node (after which the Moon rises slightly above the ecliptic) and descending node (after which the Moon sinks below the ecliptic). If the Full Moon coincides with the moment when the Moon crosses the ecliptic, we experience a lunar eclipse; if it occurs during the New Moon, we experience a solar eclipse. The Moon crosses the ecliptic about twice a month, but not always during the New Moon or Full Moon phases, so we don’t experience eclipses every time.
The Moon and planets also meet in the sky from time to time. When our natural satellite and a planet pass within a few degrees from each other in the sky, it’s called a close approach of the Moon and a planet. Sometimes the Moon even hides a planet, which is called the lunar occultation – such events are rare and can only be seen from small parts of the world.
Small Solar System bodies – asteroids, dwarf planets, and more
Most small Solar System bodies are also located near the ecliptic – such as asteroids and dwarf planets of the main asteroid belt and the Kuiper belt. However, dwarf planets are usually inclined at larger angles from the plane of the ecliptic. For example, Pluto’s orbit is tilted 17.2° from the Earth’s orbital plane.
Short-period comets (the ones that take less than 200 years to orbit the Sun) orbit close to the plane of the ecliptic, too. But not all the comets behave this way: long-period comets (those with orbital periods longer than 200 years) are randomly oriented and do not necessarily follow the ecliptic plane.
By the way, do you know the difference between an asteroid and a comet? Test your knowledge of small Solar System bodies with our quiz!
Ecliptic constellations – the zodiac and the “forgotten” constellation
Apart from the Solar system objects, you can observe stars near the ecliptic. The ecliptic intersects 13 constellations on the celestial sphere, which are the ecliptic constellations. Twelve of them are famous for their association with astrology and are called zodiac constellations. They are Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Sagittarius, Capricornus, Aquarius, and Pisces. There is a 13th “forgotten” constellation called Ophiuchus which is not part of the zodiac but is also the ecliptic constellation.
If you want to learn more about the zodiac constellations and how they relate to the zodiac signs – read our dedicated article.
Why is the ecliptic important?
You can use the ecliptic as a guideline to find the planets, zodiac constellations, and small Solar System objects in the sky above you with stargazing apps like Star Walk 2 and Sky Tonight. In these apps, the ecliptic is pictured as a yellow dotted line stretching across the sky. The most interesting targets to spot near the ecliptic are Solar System planets. To easily find them, follow these simple instructions.
Find planets with the ecliptic in Sky Tonight
The Sky Tonight app will help you find planets in a few steps:
- Step 1: Launch the app and tap the blue compass button – the app will use your device’s location to adjust the image to the real sky above you.
- Step 2: Move your device until you find the yellow dotted line on the screen – this is the ecliptic.
- Step 3: Move your device along this line, and you’ll see several large dots on the sides of the ecliptic – these are the planets.
- Step 4: If you center your device on a planet or tap on it, you will see its name. You can observe the planets in the real sky in the directions that the app shows you.
Find planets with the ecliptic in Star Walk 2
It’s as easy to locate planets with the Star Walk 2 app. To do this, launch the app and tap the compass icon in the top right corner of the screen – the app will automatically adjust the image to match the actual sky above you. Then, follow steps 2-4 in the previous guide and enjoy observing the planets.
Celestial equator and ecliptic
The Earth’s celestial equator is the circle at which the Earth’s geographical equatorial plane crosses the celestial sphere. And it’s important to note that the celestial equator doesn’t coincide with the ecliptic.
Our planet doesn’t stand upright in its orbit: the Earth’s rotational axis is inclined at 23.5 degrees from the perpendicular to the Earth’s orbital plane. Since the Earth’s equatorial plane is perpendicular to the rotational axis, it is inclined from the ecliptic plane at the same angle. As a result, the Earth’s celestial equator is inclined at 23.5 degrees from the ecliptic on the celestial sphere. And this causes a few more celestial events.
Solstices & Equinoxes
The celestial equator and the ecliptic intersect on the celestial sphere at two points – these points are known as equinoxes. They mark the transition from astronomical summer to fall (autumn equinox) and from winter to spring (spring equinox).
The two points on the ecliptic where it is at its farthest from the celestial equator are called solstices. They mark the transition from astronomical fall to winter (winter solstice) and from spring to summer (summer solstice). A hemisphere that is tilted toward the Sun at one of these points experiences the summer solstice, while the other hemisphere, tilted away from the Sun, experiences the winter solstice.
Axial precession and precession of the equinoxes
The Earth not only is tilted in relation to its orbit, but it also wobbles as it spins. Imagine a spinning top: when it moves slowly, you can see how its top traces a little circle in the air while moving. Similarly, the Earth traces a circle in space with its axis, completing one circle in about 25,800 years. This wobble of the Earth’s axis is known as the axial precession.
Due to the axial precession, the intersection points of the celestial equator and the ecliptic (i.e. equinoxes) shift slightly over time – this effect is called the precession of the equinoxes. As a result, the position of the Sun relative to the stars at these points gradually changes.
For example, about 2,000 years ago, at the point of the March equinox, the Sun was located in the zodiac constellation Aries. That’s why this point was also called the First Point of Aries. However, nowadays, the intersection points of the ecliptic and the celestial equator have shifted, and the Sun “visits” Pisces at the March equinox.
The axial precession also means that the position of the north celestial pole is not fixed. Currently, the star Alpha Ursae Minoris is closest to the north celestial pole and serves as our North Star. However, in about 13,000 years, the star Vega will be the next brightest North Star, as the Earth’s axis will point in its direction.
Do you know where to find Polaris and Vega in the sky? Test your knowledge with our quiz about the brightest stars and their locations!
Ecliptic coordinates
The ecliptic is the basis for one of the oldest coordinate systems in astronomy. It was documented as early as the 2nd century A.D. in the Almagest by Claudius Ptolemy, and it's still commonly used today. The ecliptic coordinate system describes the positions and movements of the objects within our Solar System in relation to the ecliptic. Since most Solar System objects travel close to the ecliptic plane, this coordinate system is very convenient for astronomical observations. Moreover, the plane of the ecliptic does not depend on the Earth’s axial precession, unlike the celestial equator. It is fixed in space, which makes it a reliable reference for astronomers.
F.A.Q.
What does the ecliptic represent?
The ecliptic represents the circle at which Earth’s orbital plane crosses the celestial sphere. From our perspective, it’s the apparent path the Sun takes across the sky throughout the year.
Why does the Sun appear to move across the sky?
The Sun appears to move across the sky because the Earth revolves on its axis and revolves around the Sun. The Earth’s 24-hour rotation causes the Sun to rise and set, while its 365-day orbit causes the Sun’s position to shift throughout the year.
Are all the planets on the same plane?
All the Solar System planets orbit the Sun close to the same plane, called the ecliptic plane. Although only the Earth moves on the ecliptic plane, the orbits of other planets are tilted from it by just a few degrees. This means that the planets are always located in a narrow band of the sky and can easily form planetary alignments.
What is the difference between the ecliptic and orbital planes?
The term “orbital plane” can be referred to the orbit of any celestial object around its star, while the ecliptic plane is the plane of the Earth’s orbit around the Sun.
What is the difference between the celestial equator and the ecliptic?
The ecliptic is the circle at which the Earth’s orbital plane crosses the celestial sphere. The celestial equator is the circle at which the Earth’s terrestrial (geographic) equatorial plane crosses the celestial sphere. So, these are just two separate astronomical terms.
When is the Sun on the celestial equator?
The Sun crosses the celestial equator two times a year – during the vernal and fall equinoxes.
Where does the name ecliptic come from?
The term “ecliptic” is derived from the Greek word “ekleipsis,” meaning “fail to appear.” This name was given because ancient astronomers observed that the Sun “disappeared” from the sky at the points where its path intersected with the Moon’s orbit. Therefore, the Sun’s path in the sky was named “the ecliptic” after eclipses.
Bottom line
The ecliptic is the circle at which the Earth’s orbital plane crosses the celestial sphere. It is represented as the path of the Sun across the sky throughout the year. And it’s an essential reference line in astronomy. You can use it to locate planets, the Moon, zodiac constellations, and small Solar System objects. It’s like a sky highway from which you begin your journey into the world of astronomy. Locate the ecliptic with the stargazing apps Sky Tonight or Star Walk 2 and keep an eye on it to ensure that you don’t miss out on any celestial marvels!
What Is Elongation in Astronomy: Find the Best Time to Observe Planets
In the Sky Tonight calendar, you can find such an event as “Greatest Elongation”. What does it mean, and why does it only happen to Mercury and Venus? What is common between the greatest elongation and the opposition, when planets and other celestial objects reach maximum brightness? Let’s see.
Contents
What is elongation?
In astronomy, elongation is the angular distance between a planet (or other Solar System body) and the Sun as seen from the Earth. Elongations are measured in degrees. When we say that the object has an elongation of 90 degrees, it means it is located 90 degrees away from the Sun as observed from Earth.
As the brightest object in the sky, the Sun can obscure any other star or planet. Knowing the Sun’s position, you can choose the best time for observations (when the object you want to see is farthest from the Sun). Let's look at what elongation is, using the Solar System planets as an example.
Superior and inferior planets’ configurations
The superior planets (planets that are farther from the Sun than the Earth), which include Mars, Jupiter, Saturn, Uranus, and Neptune, can reach any value of elongation from 0 to 180 degrees. For the inferior planets (planets that are closer to the Sun than the Earth), which include Mercury and Venus, the maximum elongation is about 28 degrees for Mercury and about 48 degrees for Venus. Some of the elongation values have specific names. Let’s go over them.
Conjunction
Solar conjunction is a celestial configuration in which the object has an elongation of 0 degrees, which means it is positioned at the same celestial longitude as the Sun, appearing very close to it in the sky. This alignment results in the object being obscured by sunlight, making it impossible to observe directly. Both superior and inferior planets can reach solar conjunction.
The terms “inferior solar conjunction” and “superior solar conjunction” are used in particular for Mercury and Venus. At inferior solar conjunction, the planet is between the Earth and the Sun. At superior solar conjunction, the planet is passing behind the Sun as seen from the Earth.
Quadrature
Quadrature is a position where the Sun, Earth, and the object form a right angle. As a result, the object has an elongation of 90°. This means that when the Sun sets, the object is reaching its highest point in the sky. A good example of quadrature is the First Quarter Moon, as this phase occurs when the Moon is at a 90-degree angle from the Sun. Quadrature is only possible for the superior planets.
Opposition
Opposition is a celestial alignment where the object has an elongation of 180 degrees, which is the greatest elongation for the superior planets. During opposition, the object and the Sun lie on opposite sides of the Earth, so the object is fully illuminated by sunlight and visible throughout the night. Opposition is considered to be the best time for observing a celestial body. In the dedicated article, we have a list of celestial bodies – planets, dwarf planets, and asteroids – that will reach opposition soon.
Greatest elongation: upcoming events in 2025
The inferior planets, Venus and Mercury, can’t reach quadrature and opposition. The greatest elongation possible for them is about 28 degrees for Mercury and 48 degrees for Venus. At greatest elongation, they are farthest from the Sun in the sky, so the skywatchers get the best chance to spot the planets. At greatest eastern elongation, Mercury and Venus are visible as evening objects. At greatest western elongation, they are visible as morning objects. Here's a list of the upcoming greatest elongations for Venus and Mercury.
March 8: Mercury at greatest eastern elongation
On March 8, at 05:59 GMT, Mercury will be 18° 12′ east of the Sun in the sky. The planet will be visible in the evening sky in the constellation Pisces. Mercury will have a magnitude of -0.4, visible to the naked eye. Additionally, bright Venus (mag -4.6) will shine in the same constellation.
April 21: Mercury at greatest western elongation
On April 21, at 18:59 GMT, Mercury (mag 0.3) will be 27° 24′ west of the Sun in the sky. This is Mercury's farthest elongation of the year! In addition, Mercury will form a beautiful planetary triangle with Venus (mag -4.7) and Saturn (mag 1.2) in the constellation Pisces. Look for the planets on the eastern horizon before sunrise.
June 1: Venus at greatest western elongation
On June 1, at 01:59 GMT, Venus (mag -4.4) will be 45° 54′ west of the Sun in the sky. The planet will shine brightly as the “morning star” for a few hours before sunrise in the constellation Pisces.
July 4: Mercury at greatest eastern elongation
On July 4, at 03:59 GMT, Mercury (mag 0.5) will be at 25° 54′ east of the Sun in the sky. The planet will be visible in the constellation Cancer after sunset. The Beehive star cluster will also be shining in the vicinity, and you will be able to observe the objects together with a pair of binoculars.
August 19: Mercury at greatest western elongation
August 19, at 09:59 GMT, Mercury (mag -0.1) will be at 18° 36′ west of the Sun in the sky. Observe the planet in the constellation Cancer before sunrise.
October 29: Mercury at greatest eastern elongation
On October 29, at 21:59 GMT, Mercury (mag -0.2) will be at 23° 54′ east of the Sun in the sky. The planet will be visible in the constellation Cancer after sunset. Additionally, reddish Mars (mag 1.5) will shine in the neighboring constellation Libra.
December 7: Mercury at greatest western elongation
On December 7, at 20:59 GMT, Mercury (mag -0.5) will be at 20° 42′ west of the Sun in the sky. The planet will be visible in the constellation Libra before sunrise.
Elongation and phases of the planets
Just like the Moon, planets have phases. Although in space, half of a planet is always illuminated by the Sun, the portion of the illuminated side that we can see from Earth changes depending on the planet's elongation. These phases can be observed through a telescope, and Venus, the brightest planet, can even show its phases when viewed through binoculars.
Phases of the inferior planets
As shown in the image above, inferior planets go through a full cycle of phases: from new phase at inferior conjunction to quarter phases at greatest elongations and full phase at superior conjunction. However, observing the full and new phases is extremely challenging because during these phases the planets are lost in the Sun's glare. Thus, the visible phases range from crescent to gibbous.
Phases of the superior planets
Superior planets do not display a full range of phases, but only subtle transitions between gibbous and full phases. They appear fully illuminated during oppositions, which is the best time to observe them.
Understanding elongation: to sum up
Elongation is the angular distance between a planet (or other Solar System body) and the Sun in the sky. It is measured in degrees. Planetary phases and visibility depend on elongation, which is especially noticeable for inferior planets (Venus and Mercury). Want to find out when Venus or Mercury rises in your location? Use the free Sky Tonight app. To learn the best times for viewing the superior planets, check out our article on opposition in astronomy.
Zodiac Constellations And Zodiac Signs: What Are They and How Many Are There?
Most people, even those who are not familiar with astronomy or astrology, know about the 12 zodiac constellations and their corresponding signs. But some sources claim there are 13 of them or even more. This article explains why the numbers are inconsistent and how the zodiac signs differ from the zodiac constellations. As a bonus, here you’ll find out how to spot any constellation in the night sky above you with the free stargazing apps Star Walk 2 and Sky Tonight.
Contents
History of the zodiac
The word zodiac derives from a Greek phrase meaning “animal circle,” but it’s initially the Babylonian concept, created in the 5th century B.C. Babylonian astronomers divided the band of the sky where the Sun, Moon, and planets move into equal 12 segments, each occupying 30° of celestial longitude. The segments denoted the 12 equal 30-day months and were given the names we now know as “the zodiac signs.”
The constellations along the path of the Sun, Moon, and planets in the sky had been observed even earlier. The first mentions of them belong to ancient Babylonia around 1000 B.C. They only roughly corresponded with the twelve segments of the zodiac. Still, the twelve of these constellations were given the same names as the zodiac signs. The translated names of the zodiac signs and constellations survived through the works of Greek astrologers and astronomers, one of whom was Claudius Ptolemy. In the 2nd century B.C., he wrote Tetrabiblos, which served as the basis for the Western zodiac astrology.
The zodiac was primarily an astrological concept until the heliocentric model appeared. Ancient people thought that all celestial objects revolved around the Earth, so it seemed obvious that the cosmic forces were focused on human beings. It was not until the 17th century when the telescope was invented and people realized that the Earth orbits the Sun and is not the center of the universe, that astronomical observations of the zodiac constellations gained more respect.
What are the zodiac signs?
The zodiac signs are the twelve 30° sections of the zodiac, created in analogy with the ancient “ideal year” with equal 30-day months. Most signs refer to living things, the only exception is Libra, the Scales. In modern Western astrology, the zodiac signs are supposed to affect human life somehow.
What are the zodiac constellations?
The zodiac constellations are the constellations that are located along the path of the Sun in the sky and roughly correspond to the traditional zodiac signs. Although they are historically connected to astrology, they are now as valuable for astronomical observations.
How many zodiac constellations are there?
For more than 10 years, the hype around the number of zodiac constellations hasn't dropped. Some say there are 13 or even more than 20. What causes the disagreement? Let’s clarify.
12 zodiac constellations
There are twelve constellations that roughly correspond to the traditional zodiac signs and are recognized as members of the zodiac family. These are:
- Aries;
- Taurus;
- Gemini;
- Cancer;
- Leo;
- Virgo;
- Libra;
- Scorpius;
- Sagittarius;
- Capricornus;
- Aquarius;
- Pisces.
They are called “zodiac” on behalf of tradition. Beyond that, there is no reason why they are grouped this way. Let’s see what constellations are overlooked.
13 ecliptic constellations
Astrologers say that during the dates of a zodiac sign, the Sun is “in” the corresponding constellation. Over a year, the Sun regularly visits 13 constellations in the sky: Capricornus, Aquarius, Pisces, Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Sagittarius, and Ophiuchus. The last one doesn’t have its traditional zodiac sign, but why? To find out, we would have to ask the Babylonians.
Babylonian astronomers designated the 12 zodiac signs in the 5th century B.C. They knew the 13th constellation Ophiuchus, but it didn’t fit into the ancient calendar of 12 lunar months. So, Babylonians omitted Ophiuchus for convenience. Modern Western zodiac astrology still follows the Babylonian tradition. Moreover, astronomy constellation maps don’t include Ophiuchus in the zodiac family either – it belongs to the Hercules one.
Altogether, the 13 constellations are called the constellations of the ecliptic. The ecliptic refers to the imaginary plane containing the Earth’s orbit around the Sun. We from the Earth observe it as the Sun’s path in the sky throughout the year. Over a year, the Sun appears to regularly pass in front of the ecliptic constellations one by one. The entry and exit dates almost perfectly repeat. For Ophiuchus, these dates are November 30 to December 17 (the beginning and the ending may vary by day, depending on the year and your timezone).
Therefore, if you are born at the beginning of December, don’t be surprised that the Sun is “in” Ophiuchus and not the constellation Sagittarius.
25 constellations in the zodiac belt
There is another reason to be surprised about the zodiac. Let’s forget about the tradition and assume that the zodiac constellations are the constellations located in the zodiac. In that case, we’ll get 25 of them! Here is why.
The zodiac, by the standard definition, is the band of the sky where the Sun, the Moon, and planets of the Solar System move. It occupies approximately 8° on either side of the ecliptic plane. The number of the constellations within 8° on either side of the ecliptic includes Cetus, Corvus, Crater, Hydra, Orion, Pegasus, Scutum, Sextans, Auriga, Canis Minor, Serpens, and Aquila. There are 25 of them in all. How many of these names have you ever heard?
But the Sun only passes through the 13 ecliptic constellations. Only the Moon and planets encounter the extra ones, and, sure enough, they don’t have corresponding zodiac signs.
Still, the traditional definition of the zodiac is convenient because we can refer to the same constellations in a historical and astronomical context. By this definition, the zodiac constellations are the 12 ecliptic constellations that roughly correspond to the traditional zodiac signs.
How to find the zodiac constellation in the sky tonight?
The easiest way to locate a zodiac constellation is to use a stargazing app like Star Walk 2 (download) or Sky Tonight (download). Just type the name of the constellation you're looking for in the search bar, and you'll see how it looks on the app's night sky map. Hold your phone or tablet up to the sky to align the image on the screen with what you see above. Follow the arrow on your screen, and soon you'll see the constellation both in your app and in the real sky above you.
Note that you can't see all the zodiac constellations at once, because some of them appear in the daytime sky. As the Earth moves along its orbit, the Sun appears to pass through different zodiac constellations, which means you'll see different constellations in the sky at different times of the year.
What is the difference between a zodiac sign and a zodiac constellation?
Zodiac signs and constellations are historically connected but aren’t the same. To say the least, there is a slight difference in their names: the zodiac signs Scorpio and Capricorn correspond to the constellations Scorpius and Capricornus. Even though their names sound similar, they differ as much as astronomy differs from astrology. Here are the main issues that they don’t agree on.
Telling fortunes vs. finding planets
Zodiac signs are now only used in astrology to tell fortunes and describe people's characters. Zodiac constellations are the subject of astronomy. Previously, they marked the passage of time and the seasons for ancient people and helped create calendars. Even now, they are used for marine navigation and astronomical observations. For instance, they are especially useful for amateur astronomers as reference points to locate planets.
Equal sections vs. different sizes
Zodiac signs divide the zodiac band of the sky into equal 30° sections and represent the equal 30-day months. However, the actual constellations are of different sizes and shapes. For example, the constellation Scorpius covers an area of 497 square degrees, and the Sun passes through it only for about 7 days. The constellation Virgo occupies 1,294 square degrees, and the Sun spends around 45 days in front of it.
Fixed ancient dates vs. real astronomical dates
The zodiac signs’ dates are now about a month ahead of when the Sun meets the corresponding constellations. These dates were established more than two thousand years ago, but today things changed. For example, Aries now meets the Sun around April 19 (the exact date depends on the year and your timezone) instead of the astrological date of March 21. So, most people who think of themselves as Aries were born when the Sun was in Pisces.
The reason for this time shift is the axial precession of the Earth. Our planet is like a spinning top: it’s flattened at the poles and bulges at the equator, pulled by the Moon and Sun. So, it wobbles as it spins, tracing a cone of 23.5° radius with its axis. The wobble is called the precession of the Earth’s axis, or the precession of the equinoxes. Each spin lasts one day, but each gyration around the cone takes 25,800 years. The movement slowly alters the view of the zodiac from the Earth, making the constellations appear to slide to the east about 1° per human lifetime.
Moreover, just as in ancient times, now the Sun passes through the 13th constellation Ophiuchus that we mentioned above. So, no zodiac constellation meets the Sun from around November 30 to December 17, but, in astrology, these days belong to the sign Sagittarius.
It’s the astronomical view of things. Astrologers defend themselves by saying that they use the tropical zodiac, which is fixed to seasons, not the position of constellations. So, it’s your choice to believe whether you are Aries or Pisces, Sagittarius or Ophiuchus.
Test your knowledge of zodiac signs and constellations with our engaging quiz. We bet you're ready to score really high!
F.A.Q.
Where was the Sun when you were born?
Here we provide the astronomical dates when the Sun passes through the ecliptic constellations nowadays; the beginnings and endings may vary by a day, depending on the year and your timezone:
- Aries: April 19 – May 13;
- Taurus: May 14 – June 19;
- Gemini: June 20 – July 20;
- Cancer: July 21 – August 9;
- Leo: August 10 – September 15;
- Virgo: September 16 – October 30;
- Libra: October 31 – November 22;
- Scorpius: November 23 – November 29;
- Ophiuchus: November 30 – December 17;
- Sagittarius: December 18 – January 18;
- Capricornus: January 19 – February 15;
- Aquarius: February 16 – March 11;
- Pisces: March 12 – April 18.
Are zodiac signs changing?
According to Western astrology, there are 12 zodiac signs with fixed dates that have not really changed since the 5th century B.C. As for the zodiac constellations, their positions in the sky change over the centuries, so the dates when the Sun visits a zodiac constellation no longer match the astrological dates of a corresponding zodiac sign.
Do astronomy apps show the zodiac constellations accurately?
Some users complain that Star Walk 2 and Sky Tonight apps show the incorrect positions of the zodiac constellations. For example, during the astrological dates of the zodiac sign Sagittarius, the apps show that the Sun meets Scorpius or even the 13th constellation Ophiuchus. Now you know that the zodiac signs’ dates don’t tightly correspond with the constellations’ real position in the sky. The dates used in the astronomy apps are not imagined but accurately calculated so that you can see what’s in the sky above you now. Try using Star Walk 2 or Sky Tonight to learn what zodiac constellations are visible this evening. Stargazing is no less fun than reading horoscopes!
Which zodiac constellation is the largest?
Virgo is the largest zodiac constellation and the second-largest constellation in the whole sky, after Hydra. The constellation Virgo covers 1,294 square degrees of the sky. It’s seen from November to August in both hemispheres, from latitudes between -80° to +80°. To easily find Virgo in the night sky from your location, use the stargazing app Star Walk 2.
Where are the zodiac constellations located?
The zodiac constellations are located along the Sun’s path in the sky throughout the year. To find them at night, look along the approximate path that the Sun follows during the day – from east to west across the sky. Note that you won’t see the constellation that is currently behind the Sun. Use the astronomy app Sky Tonight to locate all the zodiac constellations.
How many constellations are there on the ecliptic?
There are 13 constellations on the ecliptic: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Ophiuchus, Sagittarius, Capricornus, Aquarius, and Pisces. The 12 of them (except for Ophiuchus) are also called zodiac constellations. Test your knowledge of the constellations with this quiz!
What is zodiacal light?
Zodiacal light is a hazy pyramid of light extending up from the horizon and centered on the ecliptic. It isn’t connected to the zodiac constellations but to the band of the sky where we see them. This rare celestial event can be observed in spring and fall. Read more about the zodiacal light in our article.
Zodiac constellations and zodiac signs: Conclusion
There are 12 constellations that are traditionally called “zodiac constellations.” They are historically connected to the zodiac signs, but over the course of time, their functions of them divided. The zodiac signs now are only used in astrological horoscopes that may be fun to read but aren’t scientifically based. The zodiac constellations, on the other hand, are real groups of stars you can observe for yourself. They are explored by astronomers and can be used to locate planets and other celestial objects.
What Is Zodiacal Light – See False Dusk or False Dawn
The zodiacal light is one of the most magical and subtle sights in the night sky — a cone of light stretching from the horizon. You can easily locate it in your sky using the astronomy app Sky Tonight. Often called the “false dawn” or “false dusk,” it actually has nothing to do with the Earth's atmosphere. Curious to find out what it really is? Let's dive in.
Contents
What is zodiacal light?
The zodiacal light is a hazy pyramid of light located above the sunrise or sunset point on the horizon. It’s centered on the ecliptic – the Sun’s path in the sky that crosses the well-known zodiac constellations. This is why it's called the zodiacal light.
You might have noticed the zodiacal light, not even realizing what it is. It looks like the light of the nearby town or the lingering twilight. You might also confuse the zodiacal light with the Milky Way, and that's not surprising. It is comparably bright and even milkier in appearance, but you can tell the zodiacal light by its pyramidal shape. Under a dark sky, you can sometimes even see the real Milky Way crossing with the zodiacal light.
What causes zodiacal light?
You can distinguish the zodiacal light from the real twilight by the fact that it has no reddish tinting – the pink color is the effect of the Earth's atmosphere, but the zodiacal light comes from outside our atmosphere. In fact, it’s just the Sun's light reflecting off dust grains orbiting our star in the inner Solar System. But where do these dust grains come from? Scientists have long assumed that the space dust that causes the zodiacal light is produced by asteroids and comets. However, the new research shows that the main source of this cosmic dust may be dust storms on Mars.
Is zodiacal light false dawn or false dusk?
The zodiacal light is both false dawn and false dusk, only at different times of the year. In spring, in both hemispheres, the zodiacal light occurs right after the real dusk, so it’s called “the false dusk.” In autumn, the zodiacal light occurs just before the real dawn and is known as “the false dawn.” Note that the seasons in the Northern and Southern hemispheres are reversed.
When to see zodiacal light?
In both hemispheres, at mid-latitudes, the zodiacal light is best seen around the equinoxes. In tropical latitudes, it can be seen year-round.
Spring zodiacal light – false dusk
In spring, the zodiacal light can be seen for about an hour in the western sky. Start observing the “false dusk” about 90 minutes after sunset.
In the Northern Hemisphere, it appears in the sky in late February, reaches its maximum brightness around the March equinox, and lasts until early May.
In the Southern Hemisphere, the zodiacal light appears in the sky in late August, reaches its maximum brightness around the September equinox, and remains until early November.
Autumn zodiacal light – false dawn
In autumn, the zodiacal light can be seen for about an hour in the eastern sky. Start observing the “false dawn” about 90 minutes before sunrise.
In the Northern Hemisphere, it appears in the sky in late August, reaches its maximum brightness around the September equinox, and remains until early November.
In the Southern Hemisphere, the zodiacal light appears in the sky in late February, reaches its maximum brightness around the March equinox, and lasts until early May.
How can I see zodiacal light?
First, find a location with a dark sky, away from city lights, as the zodiacal light is faint and easily washed out by any bright source, including the Moon. The darker the sky, the better your chances of seeing the zodiacal light. Check your sky’s darkness level on the Bortle Scale with our handy infographic.
The best time to see the zodiacal light is around the equinoxes. The next one is on March 20, 2025, but it coincides with the waning gibbous Moon, which will overshadow the false dawn/dusk. Luckily, you’ll have a few months around this date to catch the zodiacal light. For the best view, choose a moonless night close to the equinox, such as March 29, 2025, when the Moon will be in its new phase.
How to find zodiacal light in the sky?
The stargazing app Sky Tonight will help you spot the zodiacal light. First, find out the time of the zodiacal light in your location:
- In the Time Machine section at the top of the main screen, select the date you want to observe the zodiacal light. The next best time to observe it is on March 29, 2025, the date of the New Moon closest to the March equinox.
- Look up the sunrise and sunset time on that date. To do this, find the Sun on the main screen (or with the app’s search), tap on it, go to the Events section, and check the Visible Passes.
- In the Northern Hemisphere, subtract 90 minutes from sunrise time – it’s when you should start looking for the zodiacal light.
- In the Southern Hemisphere, add 90 minutes to sunset time – it’s when you should start looking for the zodiacal light.
- If you don't want to miss the moment, set a reminder.
On the chosen date and time, go to a place with dark, clear skies and find the zodiacal light’s direction. Depending on your hemisphere, it's located above the sunrise or sunset point, so you need to find this point:
- In the Northern Hemisphere, tap the blue sunrise time on the chosen date in the Sun’s Visible Passes section, and the app will show you the Sun’s location on the sky map.
- In the Southern Hemisphere, tap the blue sunset time on the chosen date in the Sun’s Visible Passes section, and the app will show you the Sun’s location on the sky map.
- Tap the blue compass button at the bottom right of the screen. The app will use your device’s location to adjust the image to match the real sky above you.
- Follow the white arrow on the screen to the sunrise or sunset point. This is the direction to see the zodiacal light extending from the horizon.
F.A.Q.
Is zodiacal light related to the zodiac signs?
The zodiacal light is an astronomical phenomenon, while zodiac signs are part of astrology. The only connection is that they both share the term "zodiac," which refers to the band of the sky where the zodiacal light and constellations are found. Discover more about the zodiacal constellations and how they differ from the zodiac signs in our separate article.
What is zodiacal dust?
Zodiacal dust is a dense disc of interplanetary dust particles located near the plane of the Solar System. It is formed in a pancake-shaped cloud and is a source of the zodiacal light.
What does a false dawn mean?
A false dawn is the zodiacal light in spring. Apart from stargazing, it is significant for practitioners of the Islamic faith. It plays a role in determining specific prayer and fasting times.
What is the difference between zodiacal light and gegenschein?
Gegenschein, like the zodiacal light, is caused by sunlight reflecting off interplanetary dust, but it appears directly opposite the Sun in the sky, centered at the antisolar point. Gegenschein forms a slightly brighter, oval-shaped spot about 8-10° across within the dimmer band of the zodiacal light. Gegenschein is even more difficult to detect than the zodiacal light, requiring a perfectly dark sky and the use of the averted vision.
Zodiacal light: bottom line
The zodiacal light is a rare and beautiful celestial phenomenon that looks like a hazy pyramid of light rising from the horizon. It occurs just after dusk near the vernal equinox and just before dawn near the autumnal equinox. The next best time to see the zodiacal light is from March to early May 2025. To make sure you see this mysterious light in all its glory, pick a moonless night, head to a dark suburban location, and use the free Sky Tonight app to guide your way.
Good luck on your stargazing journey!
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