Today:   Time of rise and set of Sun and Moon.
    AAVSO Target Tool (answers the question "What should I observe tonight?")
permanently:   Call for observation: T Coronae Borealis
T Coronae Borealis (T CrB for short) is a recurrent nova about 2'000 light-years away in the constellation Corona Borealis (CrB). T Coronae Borealis is normally 10.8 mag bright, but reached 2.0 mag during the last two outbursts in 1866 and 1946. I is a so-called symbiotic star, i.e. a binary system in which an extended red giant and a compact white dwarf orbit each other at a relatively close distance. Matter from the red giant's gas envelope overflows onto the white dwarf. When a critical mass is reached, fusion processes begin, which can be observed as explosive bursts of brightness.

Apparently there are first indications that T CrB could produce a nova again during 2024. If that happens, it would be nice if we could make before/after comparisons. For this reason I would like to encourage you to take pictures of the constellation Corona Borealis resp. the star T CrB (near epsilon CrB) from time to time in the near future. For each exposure the exposure data should be recorded to use the same settings when the nova appears (this can be several different settings).

At present T CrB sets earlier and earlier. From February on it rises above the horizon again in the later evening.
For more info about T CrB see here.
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.
permanently:   Call for observation: V0959 Oph
Robert Glaisen performed brightness measurements on the star V0959 Oph (a Delta Scuti variable). He was able to determine both the amplitude and the period of the brightness variations. The remarkable thing about his results is that they do not correspond to the currently published values, neither those of the AAVSO nor of GCVS. After this finding, further observations suggest themselves. Hence the questions:
- Who has also observed the variable V0959 or has further information about it?
- Who would like to participate in a joint observation campaign? A working group could be formed for this purpose.
If further observations support Robert Glaisen's findings, we would inform the AAVSO.
Thank you for your assessments and cooperation in this interesting project.


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