Today:   Time of rise and set of Sun and Moon.
    AAVSO Target Tool (answers the question "What should I observe tonight?")
March 23, 2019:   2. Workshop about the observation of Exoplanets: The observation of variable stars goes into a new round: In addition to the classical variable stars, the observation of exoplanets also falls under the category of variables. After the first transits of exoplanets have been successfully analyzed and the results have been transmitted to an international database, we want to incorporate the gained experience and insights into the following observing campaigns and to optimize the workflow.
For more information please consult the detailed invitation.
Aug. 2017 - May 19:   Call for observation: VV Cephei
The close binary eclipsing star system VV Cephei is of type EA (Algol, beta Persei-type) and includes the components A and B. Beginning with August 2017, the giant star VV Cephei A (spectral class: M) occults his compagnion, the much smaller star VV Cephei B (spectral class: B). The orbital period is about 20.3 years, making the coming event of rare type. While the masses of both components are almost the same, the extremely giant M-star has a diameter of 15 AE (1600x the size of our sun!). That's why the eclipsing phase will last about 21 months, the minimum is expected in June 2018. The (visual) brightness of the star system will change from 4.80 to 5.36 mag.
The photographic observation is easy: The use of a tripod-mounted DSLR camera, equipped with a lens of 50mm is recommended. With an aperture of 2.8 and ISO 400, frequently taken pictures (exposure time: 13 sec.) of the specific star field are sufficient. The analyze will be done with AstroImageJ or MuniWin.
For more information please follow to BAV.
permanently:   Call for observation: RZ Cassiopeiae
The constellation of Cassiopeia is circumpolar and visible the whole night during the whole year. The star RZ Cas is a close binary eclipsing system. Its components are rounding themselves with a period of about 28.686 hours. The primary minimum lasts 4.9 hours and can be observed within one night at certain dates. The brightness varies between 6.18 (maximum) and 7.72 mag (primary minimum).
For planning of the observation, a "Time of Minimum" calculator is available.


March 3, 2018:   Meeting with Exoplanet Workshop at the Observatory Zimmerwald, considering the data reduction using the software AstroImageJ.
Invitation,  Protocol,  Script part A,  B,  C,  D