HPT- optical telescope

The HPT (Hexapod-telescope) was a prototype for an innovative new telescope-concept planned in the 1980s and finished in the 1990s. The project was sponsored by the Wirtschaftsministerium NRW and the Krupp Industrietechnik. After finishing work no more furtherances were planned, until the HPT was  taken over from the Ruhr-Universität-Bochum (RUB). This happened because of the commitment of Prof. Dr. Rolf Chini. To make the HPT work, it was necessary to improve the telescope.

Since May 1999 the HPT was set in the botanic garden of the RUB and was part of the Expo 2000. Now is the location of the HPT in Chile on the 3064m high Cerro Armazones in the Atacama desert, where AIRUB (Astronomic Institut of the RUB) works with another smaller telescope in cooperation with the University of Antofagasta. The migration was sponsored by the Wissenschaftsministerium NRW again, the project itself is sponsored for the period of 15 years by the Academy of Science of NRW. Today the HPT is used by some RUB-astronomers and Prof. Dr. Rolf Chini himself to watch the development of new stars and quasars. This isn’t possible normally because the time each team has with a telescope is limited. To fulfill this new exercise the HPT was improved again. A telescope-robot with a camera was added to help the HPT to find interesting things to look at and a spectograph was sponsored.

 Characteristics are the hexapod mounting instead conventional design with azimut- and elevation axis and the thin, lightweight mirror. The mirror is stiffened with a framework made of carbon fiber composite struts and invar nodes. The hexapod mounting is more precise than conventional mountings and offer more degrees of freedom. The thin mirror reaches thermal stability in a very short time compared to conventional, thick mirrors; a higher quality image is achieved. The mirror is mounted with piezo elements to the framework. The mirror surface is actively controlled. The subreflector is connected to the telescope with its own hexapod mounting. So the subreflector has 6 degrees of freedom with respect to the telescope mirror. The whole telescope is lightweight design and saves substantially weight compared to conventional designs, in turn precision is enhanced.

One of the six main strut drives of the telescope.


Framework structure for mirror support

View of the framework mounted on the main hexapod struts.

One strut of the framework.

Systemtolerance of one knot +-2µm

Subrefelctor - mounting

One of six subreflector actuators. Design and production of the subreflector actuator were made by BOEHM.