SIMBAD references

First CCD photometric measurements of the RRab star SW Boo were obtained. Although the observed scatter in the reduced lightcurve may be intrpreted as an idication for Blazhko effect, the fluc- tuations in brightness in maximum and minimum light are some 5- 10 times lower then results from visual observations given in the literature (1). Further observations will be needed to study that contradictory result. The star is also known as showing quite a large secular period change (2). The recent CCD-observations re- veald large (O-C) = +4.7 hours using elements from GCVS (5). So instantaneous elements derived from the new CCD observations (for the recent epoch after 2450000) are proposed: E0=2452368.57 and P=0.5134977(d). The mean "rise time" was (M-m)/P=0.068 ± 0.010. This value did not vary much and showed no significant indication for irregularities. It is completely in agreement with the litera- ture value of 0.065 (2). Also no statistically significant (O-C)- scatter has been identified from the CCD measurements.