☄ Olbers 13P/Olbers

How to follow comet Olbers live

The panel above recomputes the position of Olbers every second in your browser: its distance from the Sun and from Earth, its position in the sky (right ascension and declination), and a live countdown to the next perihelion. It runs on the same kind of engine observatories use, a Kepler solver applied to the JPL osculating orbital elements, so the numbers are not a static snapshot, they keep ticking.

Just below, the top-down map of the Solar System shows exactly where Olbers is right now among the planets. You can fast-forward time with the day slider, zoom and pan, compare its distance to another body with a click, and press "Next event" to jump straight to perihelion. It is the most direct way to grasp the orbit of Olbers with no math at all.

Comet fact sheet

About Olbers

Heinrich Wilhelm Matthias Olbers was a physician in Bremen who devoted his nights to the sky. On March 6, 1815, he located a comet that would bear his name and would not be seen again by Earth-based observers for nearly seventy years. 13P/Olbers belongs to the Halley-type class, with a period between 20 and 200 years, placing it in a category apart from short-period Jovian comets: each return is a rare event for the generation that witnesses it, and the comet carries at its surface materials preserved since the formation of the Solar System 4.6 billion years ago.

The 2024 return was the best twenty-first-century observing opportunity for 13P/Olbers. With perihelion on June 30, 2024, the comet reached magnitude 6 to 7, visible in 10x50 binoculars under dark skies. No adult observer from 2024 will live to see the next perihelion in March 2094.

History and discovery

Olbers discovered the comet on March 6, 1815 during one of his nightly observing sessions in Bremen. It passed perihelion on April 26, 1815 and reached about magnitude 5, remaining faintly visible to the naked eye for several weeks. The event occurred a few months before the Battle of Waterloo, and period accounts mention that the comet was spotted by many Europeans who already had their eyes on the sky for both astronomical and political reasons.

The same Heinrich Olbers is credited with foundational contributions to astronomy beyond the comet: he discovered the asteroids Pallas (1802) and Vesta (1807), becoming one of the first to map the asteroid belt, and formulated what is known as Olbers's Paradox in 1823, the question of why the night sky is dark if the universe contains infinite stars. His comet returned in 1887, 1956, and most recently in 2024, each return witnessed by a different generation of observers.

Orbit and returns

13P/Olbers has an orbital period of about 69 years, classifying it as a Halley-type comet. Its perihelion sits at 1.18 AU from the Sun, slightly inside Earth's orbit, while aphelion reaches values above 30 AU in the trans-Neptunian region. Each complete cycle carries the nucleus from an extremely cold and dark environment to the immediate neighborhood of the Sun, with all the thermal and sublimation cycling that implies.

The 2024 return was well documented: the comet passed perihelion on June 30, 2024, when it was 1.18 AU from the Sun and 1.94 AU from Earth. The SWAN instrument aboard SOHO detected a water production rate of 1.1 x 10^29 molecules per second on June 3, 2024. The observed magnitude reached 6 to 7, brighter than initially expected and similar to the 1956 return (magnitude 6.5). The next perihelion is forecast for March 20, 2094.

Nucleus and family

The nucleus of 13P/Olbers has not been studied directly by any spacecraft mission. Estimates based on photometry of the inactive nucleus suggest a diameter of roughly 10 to 15 km with a very low albedo, typical of Halley-type comets. As a member of this class, 13P has an orbital inclination of about 44 degrees to the ecliptic plane, intermediate between the low-inclination Jovian comets and highly inclined or retrograde comets.

The surface composition likely combines water ice, carbon dioxide, and carbon monoxide ices with dark refractory organic material. Each perihelion pass removes surface layers by sublimation, exposing deeper material that has never been heated. Halley-type comets like 13P are considered time capsules of the primitive Solar System: each return offers a window into pre-solar chemistry.

• Orbital period: ~69 years
• Perihelion: 1.18 AU
• Aphelion: >30 AU (trans-Neptunian region)
• Orbital inclination: ~44 degrees
• Classification: Halley-type comet
• Water production rate in 2024: 1.1 x 10^29 molecules/second (SOHO/SWAN)

How to observe

The 2024 return was the best twenty-first-century observing opportunity for 13P/Olbers. At magnitude 6 to 7 in June 2024 it was accessible to 10x50 binoculars under dark skies, appearing as a diffuse patch with a condensed nucleus and the start of a tail. Photographically, small telescopes revealed coma structure and a tail several degrees long. Perihelion on June 30, 2024 marked the point of maximum brightness.

For those who missed the 2024 return, the next opportunity will be in 2094. Practically speaking, the 2024 return was definitive for all current adult observers. Photographic records from the 2024 return are archived at sources including NASA's APOD (Astronomy Picture of the Day) and the British Astronomical Association Comet Section database.

• 2024 return: magnitude 6 to 7, visible in 10x50 binoculars
• Best 2024 window: June and July (pre- and post-perihelion)
• Next perihelion: March 20, 2094 (beyond current observers' lifespans)
• 2024 image archive: BAA Comet Section, NASA APOD

Science and historical observations

Halley-type comets like 13P are especially interesting for science because, unlike Jovian comets, they have spent less time in the hot inner Solar System. Each passage strips material from the surface, but the nucleus preserves a deep layer of primitive compounds that have never been heated. Spectroscopy of comets in this class has detected complex organic molecules that have provided clues about pre-solar chemistry.

The 2024 return was monitored by several instruments, including SOHO/SWAN for water production measurements and ground-based spectroscopy for coma composition. Data collected in 2024 will be compared with those from 1956 (where available) to detect possible changes in activity level between the two returns, separated by 68 years. This comparison may reveal whether the nucleus is losing sublimation capacity over successive passes or maintaining stable activity.

Facts

• Heinrich Olbers was a physician who never worked professionally as an astronomer, yet he discovered two of the first known asteroids (Pallas in 1802 and Vesta in 1807) and formulated Olbers's Paradox, still taught in cosmology courses today.
• Olbers's Paradox (1823) asks: if the universe were infinite, uniform, and eternal, the night sky should be uniformly bright. The paradox is resolved by the expansion of the universe and the finite age of the cosmos, which limits how far light can have traveled to reach us.
• The 2024 return was the first since 1956: no observer under 20 in 1956 was alive in 1887, and no adult from 2024 will live to see 2094, making each return a once-in-a-generation event.
• The magnitude 6 to 7 reached in 2024 was brighter than the initial forecast of magnitude 7 to 8, a pleasant surprise for observers worldwide.
• 13P/Olbers has no confirmed associated meteor shower; its orbit crosses Earth's at an angle that produces insufficient debris flux for detectable activity.
• Olbers signed his astronomical papers simply as "H. Olbers," which led some older texts to misspell the name as "Obers" or "Ulbers."

Other comets

See the full comet catalogue.