SIMBAD references

Maximum timings of the RRab star AR Herculis were obtained by CCD photometry. Instantaneous elements (for the most recent epoch after 2447000) are derived from photographic and visual maxima available from the RR-Lyrae database (1) and from the new CCD-observations (see table 1): E0= 2447981.423; P= 0.4699846 (d). The CCD-observations reveald a clear variation in the O-C-value by some 1.5 hours within a few days. The "rise time" (m-M)/P also differed significantly from 0.177 ± 0.016 to 0.297 ± 0.021 (literature value: 0.20 (2)) bet- ween the observations. The observed variations may be interpreted to be due to a Blazhko-effekt which has been recognised already by Balazs and Detre (3) in the 1930s.