Dutch Open Telescope

The Dutch Open Telescope is a solar telescope located at Roque de los Muchachos Observatory on La Palma in Spain. Its mirror measures 0.45 meters across and operates at an elevation of about 2350 meters to observe and study the sun's surface in fine detail.

The telescope started operations in 1997 and introduced a new approach to solar observation with its open design. This concept represented a shift away from the traditional enclosed vacuum-style telescopes that had been used before.

The facility was created through international cooperation between Dutch and Spanish research institutions working together on solar studies. Scientists from around the world visit to investigate how the sun changes and affects space weather.

The mountain location provides clear air and minimal air pollution, which is essential for accurate observations. Visitors should bring warm clothing since the high elevation means cooler temperatures throughout the year.

The open design allows warm air to circulate around the mirror, keeping it at a constant temperature. This system prevents the mirror from warping due to heat changes that would otherwise distort observations.

Inception: 1997

Elevation above the sea: 2,350 m

Diameter: 0.45 m

Part of: Roque de los Muchachos Observatory

Website: http://dot.iac.es

GPS coordinates: 28.75964,-17.88132

Latest update: December 12, 2025 17:45