200 nights with μ Herculis: early results from the SONG Hertzsprung telescope
Jørgen Christensen-Dalsgaard (Stellar Astrophysics Centre, Aarhus University), Frank Grundahl (Stellar Astrophysics Centre), Mads Fredslund Andersen (Stellar Astrophysics Centre), Hans Kjeldsen (Stellar Astrophysics Centre), Pere Palle (IAC), et al.

The SONG Hertzsprung telescope, at the Observatorio del Teide, Izana, Tenerife, is a prototype for the telescopes in the planned SONG (Stellar Observations Network Group) network for asteroseismology and exoplanet studies. It has an aperture of 1 m and is equipped with a high-resolution spectrograph, with an iodine reference, and a two-channel lucky-imaging camera. Operations are fully robotic. The telescope entered operation in the Spring of 2014 and, as one of the first extended observing programmes, has observed the V = 3.42 subgiant μ Herculis (HD 161797) for a total of 200 nights in 2014 and 2015. This has yielded excellent data on the oscillation frequencies, with a clear indication of mixed modes, and other oscillation properties. I present these observations, demonstrating the excellent quality of the telescope and instrumentation, and discuss the first inferences from the analysis of the results.