Small Radio Telescope 3m (KRT3)

The Observatory's Kleine Radioteleskop 3m (KRT3) became operational on the roof of the main building in autumn 2019. The instrument is equipped with a parabolic dish of 3 m diameter and with a digital receiver for a wavelength of 21 cm (1420 MHz). With the KRT3 instrument the continuum of bright radio sources and the 21cm line of atomic hydrogen can be observed.

KRT3 is used for an exercise in the advanced practical class (PHY-FP), a module of the physics curriculum, and in the Ferienkurs for high-school students from the municipal region Hamburg, and for public outreach, as on Open Days or the Long Night of the Sciences.

Technical Information

KRT3 is a SPIDER 300A model purchased from the company Primaluce Lab / Italy. It replaces the former KRT3 radio telescope from CASSI Corp. (USA), which was in operation since 2011.

The new radio telescope is made of a parabolic dish of 3 m diameter and a digital receiver. The telescope has an azimuthal mounting, allowing to move the antenna freely in azimuth and elevation. The antenna is made of a thin wire mesh supported by a frame of aluminium, which reflects the incoming microwave radiation and focuses it on the feedhorn.

Receiver type: digital superheterodyne receiver
Frequency range of the pre-amplifier: 1400-1440 MHz
Width of the main beam: about 5°
Pointing accurary: 1°

Example spectrum

Example for a spectrum of interstellar hydrogen in the Milky Way observed with KRT3. The antenna temperature is shown as a function of the radial speed at a galactic longitude of 80 degrees. The solid blue line shows a comparison spectrum of the Leiden-Argentine-Bonn (LAB) sky survey.