Comet seeker
A short-focal-length telescope for comet hunting.
A comet seeker is a compact telescope designed specifically for comet hunting, with a short focal length and wide aperture to maximize light brightness. This telescope type led to the 1848 discovery of the asteroid 9 Metis.
Its design features a short focal length paired with a broad field of view. Notable examples include a 3.9-inch aperture model installed at the United States Naval Observatory in 1843, later transferred to the Smithsonian Museum in 1866. This 4-inch (10.2 cm) instrument, made by Utzschneider & Fraunhofer in Munich, was part of a larger suite of observatory equipment. Markree Observatory used a 3-inch aperture comet seeker on an equatorial mount by Ertel, ordered in 1842 and in service until 1874. That instrument was used by Andrew Graham, assistant to Edward Cooper, to discover 9 Metis in April 1848; Graham also sketched the Orion nebula with it. An 8.6-centimeter (3.4 in) aperture comet seeker, with modifications, helped produce the Bonner Durchmusterung star catalog at Bonn Observatory in the 19th century. In 1866, Marseille Observatory acquired an 18-centimeter (7.1 in) aperture comet seeker by Martin.
- Aperture example 1
- 3.9 inches (later described as 4 inches, 10.2 cm)
- Aperture example 2
- 3 inches
- Aperture example 3
- 8.6 cm (3.4 in)
- Aperture example 4
- 18 cm (7.1 in)
- Discovery
- 9 Metis in April 1848
- Maker example 1
- Utzschneider & Fraunhofer
- Maker example 2
- Ertel
- Maker example 3
- Martin
Lore & Background
The comet seeker is an optical device known for having a short focal length but a wide field of view. A comet seeker with about 3.9 inch aperture was installed at the United States Naval Observatory in 1843, and later transferred to the Smithsonian Museum in 1866; it had an aperture of 4 inches (10.2 cm) and was made by Utzschneider & Fraunhofer in Munich. This instrument was operated as part of a suite including a larger refractor on an equatorial mounting, a meridian transit, mural circle, and others.
Markree Observatory added a 3-inch aperture comet seeker on an equatorial mount by Ertel, ordered in 1842 and in place until 1874. This Markree comet seeker was used to discover 9 Metis in April 1848, discovered by Edward Cooper's assistant Andrew Graham, who worked at that observatory until 1860. Graham also observed and sketched the Orion nebula with this Ertel comet seeker.
An 8.6-centimetre (3.4 in) aperture comet seeker was used, with some customizations, to produce the Bonner Durchmusterung star catalog from Bonn Observatory in the 19th century. In 1866 a comet seeker telescope of 18 centimetres (7.1 in) aperture by Martin was acquired by the Marseille Observatory in France.
Reader's Guide
The comet seeker's significance lies in its specialized design for comet hunting, prioritizing light gathering and a wide field of view through a short focal length and large aperture. Its legacy is demonstrated by its use in notable discoveries and astronomical work: the Markree Observatory's 3-inch Ertel comet seeker discovered the asteroid 9 Metis in 1848, and the same instrument was used by Andrew Graham to observe and sketch the Orion nebula. Another comet seeker, with an 8.6 cm aperture, contributed to the Bonner Durchmusterung star catalog from Bonn Observatory, a major 19th-century survey. The United States Naval Observatory installed a comet seeker in 1843, later transferred to the Smithsonian Museum in 1866, indicating its institutional value. The Marseille Observatory acquired an 18 cm aperture comet seeker by Martin in 1866, showing continued adoption. These examples illustrate the comet seeker's role as a practical tool for both discovery and cataloging, though the article does not discuss its broader impact beyond these specific uses.
Did You Know?
- A comet seeker was used to discover the asteroid 9 Metis in 1848.
- A 3.9-inch aperture comet seeker was installed at the United States Naval Observatory in 1843.
- Andrew Graham used an Ertel comet seeker at Markree Observatory to sketch the Orion nebula.
- An 8.6 cm aperture comet seeker helped produce the Bonner Durchmusterung star catalog.
Frequently Asked Questions
What is a comet seeker in astrophotography?
A comet seeker is a small, purpose-built telescope optimized for sweeping the sky in search of comets. It pairs a short focal length with a wide aperture so it can collect enough light to reveal faint, fast-moving objects.
What famous discovery is linked to a comet seeker?
The compact comet seeker at the United States Naval Observatory was the instrument through which the asteroid 9 Metis was identified in April 1848.
Where was the original 3.9-inch comet seeker telescope located?
It was installed at the U.S. Naval Observatory in 1843 and, after years of service, was transferred to the Smithsonian Museum in 1866.
Who manufactured the well-known Munich comet seeker?
The instrument was built by Utzschneider & Fraunhofer in Munich and formed part of a broader suite of observatory equipment rather than standing alone.
How does a comet seeker differ from a typical research telescope?
Instead of long focal lengths and narrow fields of view, a comet seeker uses a short focal length and broad aperture to cover a wide swath of sky at once, making it ideal for spotting faint comets rather than resolving fine detail on a single target.
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