Inaugurated in December 2009, the observatory has now received its future main instrument after a planning and installation phase lasting more than two years. The CDK 20 from PlaneWave Instruments is a Dall-Kirkham modified Cassegrain telescope with an additional corrector. The telescope is supported by a GM 4000 QCI mount from the Italian company 10Micron. The mount precisely tracks the apparent motion of the sky.
Telescope and mount were purchased by the University of Würzburg, because this special instrument is used not only by students of the FKG but also by students of the University of Würzburg in the context of seminars and astronomical practical courses. Like all facilities of the scientific students' laboratory, the observatory is also open to pupils of other schools.
The new telescope is the heart of the cooperation project "Brightness fluctuations of active galaxy nuclei". In this project, which is probably unique in Germany, students of the students' laboratory together with scientists from the Chair of Astronomy measure the brightness of the centers of selected galaxies at regular intervals. With the help of these data, the masses and distances of the two black holes can be determined, which are assumed to be the central machine in the centers of active galaxy nuclei. These measurements complement the research work of the group led by Prof. Dr. Karl Mannheim, who is using the MAGIC telescope system on La Palma to study the same objects in the gamma-ray range. By involving students in current research, they become enthusiastic about the natural sciences, which paves the way for scientific studies.
The reflecting telescope is supplemented by a refracting telescope with an aperture width of 12 centimeters. The apochromatic refractor ED 120 from Sky-Watcher is used to observe objects with a larger angular extent and at the same time functions as a guide tube with which the reflecting telescope can be controlled with the highest precision. This telescope could be purchased with the support of the Verein der Freunde des FKG e.V.
At the inauguration of a larger telescope - the astrograph now set up is one of the larger instruments of its kind in northern Bavaria - there is always the solemn moment of the first astronomical observation: the so-called "First Light", i.e. the first starlight that falls on the mirror after the telescope has been set up, aligned and adjusted. In addition to numerous schoolchildren and students, parents, teachers, the board of the FKG Sponsors' Association, as well as scientists and professors from the Faculty of Physics had gathered for this event. The municipality of Hettstadt, which provided the land for the observatory, was represented by Mayor Eberhard Götz.
The "First Light" was also the occasion to give the observatory a name. The first professor of astronomy at the University of Würzburg and one of the pioneers of the European Southern Observatory (ESO), Prof. Dr. Hans Haffner, was chosen as the patron saint of the name. Professor Haffner worked at the University of Würzburg from 1967 until his death in 1977 and was also instrumental in the establishment of the former university observatory and today's public observatory in the Keesburg. At the naming ceremony, Haffner's successor in office, Prof. Dr. Karl Mannheim, also read out a handwritten letter from the widow, Friedhilde Haffner, in which she thanked her husband for his merits and gladly agreed to the naming.
In the first weeks after the First Light, schoolchildren and students from the University of Würzburg were able to gain their first practical experience with this telescope. After months of theoretical preparation and familiarization of the students, the research project could now also enter the practical phase.
In keeping with Haffner's intentions, the observatory is now a place where young people - pupils and university students alike - can come into contact with the fascinating field of practical sky research for the first time.
