The large telescope
The longest moveable refracting telescope on Earth is 21 meters long and is still today the main highlight of attraction at the Archenhold Observatory. With its lens diameter of 68 centimetres, it is nevertheless still at 8th place of the world ranking list of large refracting telescopes. Therefore, it has been correctly called the Treptow Giant Telescope since its installation in the year 1896.
Here, for the first time, important design features were created which were later generally used in the instruments of astronomy. Thus, it was logical to protect this equipment in the year of 1967, as part of a monument of technology.
The fact that it can still be used today has to be attributed to the extensive maintenance measures in the recent past. Indirectly, the large telescope owes its existence to the Industrial Show of 1896.
The young scientist Friedrich Simon Archenhold reached the boundaries of his work in 1892 - due to a lack of modern telescopes in Germany. He risked everything in order to remedy this with a large telescope. The only eligible financing of this telescope was to display it at an exhibition.
Despite many financial and technical difficulties, F.S. Archenhold succeeded in showing his telescope to the citizens of Berlin at the Industrial Show in 1896. The citizens of Berlin came in huge crowds and with the agreement of the municipal authorities, it was allowed to remain standing there after the end of the exhibition "till further notice".
Lens diameter 68 cm, total mobile mass 130 tons Magnification: 210-fold, the telescope is particularly suitable for observations of the moon and planets due to its high magnification.
The telescope does not stand, as is usual, under a dome since this must then have a diameter of nearly 50 meters.
The only protection from the natural elements is a retractable roof, along with a protective cylindrical exterior shell around the actual telescope module.