The Jacobus Kapteyn Telescope or JKT is a 1-metre optical telescope named for the Dutch astronomer Jacobus Kapteyn (1851–1922) of the Isaac Newton Group of Telescopes at the Roque de los Muchachos Observatory on La Palma in the Canary Islands, Spain.

Jacobus Kapteyn Telescope

The Jacobus Kapteyn Telescope in 2011 against a background of clouds as the sun rises
Alternative names	JKT
Named after	Jacobus Kapteyn
Part of	SARA
Location(s)	Roque de los Muchachos Observatory, Garafía, Province of Santa Cruz de Tenerife, Canary Islands, Spain
Coordinates	28°45′40″N 17°52′41″W / 28.76117°N 17.87808°W / 28.76117; -17.87808
Organization	SARA Isaac Newton Group of Telescopes
Altitude	2,369 m (7,772 ft)
First light	23 March 1984
Telescope style	astronomical observatory reflecting telescope
Diameter	1.0 m (3 ft 3 in)
Mass	40 t (40,000 kg)
Mounting	equatorial mount
Website	www.ing.iac.es/PR/jkt_info/
Location of Jacobus Kapteyn Telescope
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Funded jointly by the Netherlands and the United Kingdom with planning throughout the 1970s, construction of the JKT was completed in 1983 with the first photographic plate taken in March 1984. It can be used with two different focal points and different instruments, although by 1998 this was refined to one CCD imaging instrument. The telescope weighs nearly 40 metric tons in total.^[1]

During construction in 1983, a Spanish container ship carrying parts of the telescope to La Palma was involved in an aircraft incident. In what is known as the Alraigo incident, a British Royal Navy Sea Harrier fighter jet made an emergency landing on the base plate for the telescope.^[2]

Being superseded by more recent and larger telescopes, it was taken out of service as a common-user facility in August 2003.

Since 2014, the telescope is owned by the Instituto de Astrofísica de Canarias (IAC) and operated by the Southeastern Association for Research in Astronomy (SARA)^[1] which has retrofitted JKT as a remotely operated observatory (under the internal designation SARA-RM), with the first new observations in this regime in April 2016.