Lichtgedanken 04

S C HW E R P U N K T 35 04 | LICHT GEDANKEN mode: additional reflectors in the beam path direct the light collected by the main reflector out of the tube of the telescope and focus it on a fibre optic, which is connected with the spectro- graph. The light is segmented into its spectrum colours there and the spectra of the stars are recorded. The sunset sparks activity in the control room I am reminded of an aeroplane cockpit, in which all of the instruments need to be checked prior to take-off—the atmosphere in the silent, now almost totally dark clearing in the forest has an almost hectic edge to it. Mugrauer keeps returning his attention to the screen, which is reporting the status of the sun. But what I consider to be »to- tal darkness« is not sufficient for the astrophysicists. More test recordings are made with the telescope and the signal strength checked for the various colour ranges. Then, finally, the sun lies twelve degrees below the horizon; we have reached »nautical darkness« and the first observation can begin. This observation concerns the spec- troscopic investigation of a double star with an unpronounceable name, comprising three letters and a six-dig- it number. Markus Mugrauer lets me enter the coordinates of the target ob- ject into the computer and, two mouse clicks later, the telescope and dome above our heads rattle and rumble in movement and can surely be heard throughout the dark forest. After a few seconds it is once again quiet, and the first stars appear on the monitor. One look at the map in the observation handbook and Mugrauer has quickly identified our target object amongst the bright dots, which now fill the display window. It is several dozen light years away, in the centre of the Camelop- ardalis constellation. Camelopardalis? Susanne Hoffmann shows me a pic- ture of the huge Giraffe, which can be seen over the northern sky throughout the year. I decide that I really need to refresh my knowledge of the constella- tions. And it continues: after a short test recording, our double star is aligned with the glass fibre entry to the spectro- graph; Mugrauer moves the star using arrow keys so it sits within a crosshair on his monitor. Another click and the recording of the first spectrum begins. During the measurement, we can see the star flickering and sparkling in his crosshair. But wait, weren’t we talk- Dr Markus Mugrauer runs the University Observatory in Großschwabhausen. Top image: The 90-centimetre reflector telescope is five metres tall, weighs 13 tonnes and has been in operation since 1962.