Last chances in 2023 to see comets from home without using a telescope •
comets in the night sky

Last chances in 2023 to see comets from home without using a telescope

Stargazing is an accessible activity for families and a perfect excuse to introduce children to astronomy. To begin, parents can teach their kids basic information about the cosmos, such as major constellations, planets, comets and the Moon.

This is a perfect time to explore the night sky. With most businesses and stores closed in cities worldwide, the stars shine brighter, and it’s easier to see them due to reduced light pollution. Here are some ideas to get started as a family:

Observation tools

All you need is a view of the sky and a pair of eyes, although binoculars and affordable telescopes can enhance the experience.

A pair of 7×50 binoculars, the most popular size, is ideal for observing stars. As for family telescopes, the two main types are refractors and reflectors that focus starlight using mirrors. The key features to look for in a telescope are high-quality lenses, a sturdy mount, and a set of three eyepieces that you can use to change the magnification.

Here we list the last comets that you will be able to see with your family from home, you will only have 4 opportunities this year.

Bright comets you can see in the night sky this year

Updated: 11-July-2023

The following table displays the currently visible bright comets as well as the upcoming comets expected to exhibit brightness in the future (with a magnitude above 11.5 and one year in advance). It provides information about each comet’s maximum visibility, brightness level, and the latitude range from which it can be observed during that peak.

Comets that have entered the outward phase (post-perihelion) are excluded from the table once their magnitude drops below 12th magnitude.

Additionally, an icon is provided next to the brightness values (magnitude) to suggest the minimum recommended instrument for observation. However, please note that this indication serves as a general guide and may vary depending on factors such as the comet’s characteristics, observing conditions, and the specific instrument used.

C/2021 T4 (Lemmon)

Comet Lemmon, also known as C/2021 A1 (Lemmon), is a comet that was discovered on January 3, 2021, by the Mount Lemmon Survey in Arizona, United States. It was named after the observatory where it was first observed.

This comet is classified as a long-period comet, indicating that it originates from the Oort Cloud, a distant region of the solar system filled with icy bodies. Comet Lemmon has an elongated orbit that takes it far beyond the orbit of Neptune and brings it closer to the Sun during its perihelion.

The perihelion, which is the point in the comet’s orbit closest to the Sun, occurred on May 9, 2021, at a distance of about 0.73 astronomical units (AU) from the Sun. After its perihelion passage, the comet began its journey back into the outer regions of the solar system.

Comet Lemmon has been visible primarily from the southern hemisphere, offering stargazers and astronomers in those regions an opportunity to observe its unique characteristics. It has exhibited a coma, a hazy cloud of gas and dust surrounding its nucleus, which is the solid core of the comet.

The coma is formed as the heat from the Sun causes the icy nucleus to vaporize and release gases and dust into space.

How bright will it be?

Although predictions about a comet’s brightness can be challenging, Comet Lemmon reached its peak magnitude of around 6 in late May 2021, making it visible to the naked eye under dark sky conditions. The comet will gradually fade and become more challenging to observe as it continues its journey away from the Sun.

Comets like Lemmon provide scientists with valuable insights into the composition and evolution of the early solar system. By studying their structure and composition, researchers can gather information about the formation of planets and the delivery of water and organic molecules to Earth.

Observing and studying comets like Lemmon serve as a reminder of the dynamic nature of our solar system and the beauty of celestial objects that grace our night sky.

More about comets

Comets are celestial objects that originate from the distant regions of our solar system. Characterized by glowing heads and elongated tails, comets comprise a core, or nucleus, made up of rock, dust, and frozen gases. When they approach the Sun, their icy cores heat up, causing a glowing envelope of gas and dust, known as a coma, and often a tail, to form.

Classification of Comets

Comets divide into two main categories based on their orbital periods: short-period and long-period comets.

Short-period comets, also known as periodic comets, have orbits that take less than 200 years to complete. They usually trace their paths in the region of the solar system known as the Kuiper Belt. The most famous of these is Halley’s Comet, which reappears approximately every 76 years.

Long-period comets have more elongated orbits, taking more than 200 years to orbit the Sun, with some requiring thousands or even millions of years.

They generally originate from the Oort Cloud, a hypothetical spherical cloud enveloping the solar system at a distance approximately 1,000 to 100,000 astronomical units from the Sun.

Anatomy of a comet

Comets comprise three main parts: the nucleus, the coma, and the tail.

The Nucleus

The nucleus, the solid core of the comet, contains a mix of rock, dust, water ice, and frozen gases such as carbon dioxide, carbon monoxide, methane, and ammonia. Its size can range from a few hundred meters to tens of kilometers in diameter.

The Coma

As a comet nears the Sun, solar heat evaporates the ices in its nucleus, leading to the formation of a large, glowing envelope of gas and dust called the coma. The Sun’s radiation also ionizes the coma, which can result in a type of glow distinct from that caused by reflected sunlight.

The Tail

Cometary tails form as solar radiation and solar wind exert pressure on the coma, blowing gas and dust away from the Sun to form two distinct tails — a dust tail and an ion tail. The dust tail, which reflects sunlight and often appears yellowish, follows a curved trajectory, while the ion tail, which glows due to fluorescence and usually appears bluish, points directly away from the Sun.

Observation and study of comets

Comets have been a subject of fascination for millennia, with records of their observations dating back to ancient civilizations. Astronomers observe comets to study the early solar system, as comets are ancient bodies that preserve the original materials from which the solar system formed.

Modern studies utilize a range of equipment from ground-based telescopes to space missions. Notable space missions to comets include NASA’s Stardust mission, which collected dust samples from Comet Wild 2 and returned them to Earth, and the European Space Agency’s Rosetta mission, which deployed the Philae lander onto the surface of Comet 67P/Churyumov-Gerasimenko, marking the first successful landing on a comet.

Comets and life on Earth

Comets may have played a crucial role in the emergence of life on Earth. Some theories suggest that comets could have delivered water and organic compounds — the building blocks of life — to the early Earth. The study of comets thus may provide vital clues about the origins and evolution of life.


Comets, these intriguing celestial travelers, have captivated human interest throughout history. They provide a crucial link to understanding the early solar system and potentially the origin of life on Earth.

As our technological abilities evolve, the continued exploration and study of comets promise to reveal even more about these remarkable objects and their place in our cosmic neighborhood.

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