We present new accurate CCD uvby light curves for the LMC eclipsing binaries HV 982 and HV 12578, and for the SMC systems HV 1433 and HV 11284 obtained at the Danish 1.5m telescope at ESO, La Silla, equipped with a direct camera and CCD #28 (a thinned 1024x1024 Tek device), during several periods between November 1992 and November 1995. The light curves were derived from DoPHOT photometry, and typical accuracies are between 0.007 and 0.012mag per point. Standard uvby indices have also been established for each binary, primarily for determination of interstellar reddening and absorption. For HV 982 and HV 12578, accurate photometric elements have been established. Both systems consist of two detached components of comparable sizes in an eccentric orbit.
Differential Stroemgren uvby observations from the Four College Automated Photoelectric Telescope are presented for the magnetic CP (mCP) stars HR 2258, MW Vul, and HR 9017 and the HgMn star 46 (rho) Aqr.
Four College Automated Photoelectric Telescope differential Stroemgren uvby photometric observations of four magnetic chemically peculiar stars are presented. One of our comparison stars was also found to be variable. Observations of the sharp-lined Si star HD 11187 are best described as representing a constant star. HD 15144 was also constant photometrically. However, its comparison star HD 14940 is definitely variable. But we were not able to find a period. It may be a {delta} Scu star. Our observations of 20 Eri and the uvby values of Renson & Manfroid show definite differences in the shapes of the light curve which suggest that this star may be undergoing a precession of its rotational axis. When we refined the period by using the minima we find a value of 1.92893 days. We refined Winzer's period of the relatively large amplitude variable HR 8933 to 2.86031 days. In v and b there are definite indications of a weak submaximum within the broad minimum.
Differential Stroemgren uvby photometric observations from the 0.75-m Four College Automated Photoelectric Telescope were obtained for three metallic-line and three Mercury-Manganese stars. None were found to be variable. These sharp-lined stars may not be the best tests for class variability as their polar axes are pointed towards the earth. Each presents essentially the same visible hemisphere as it rotates.
Differential Stroemgren uvby photometric observations from the Four College Automated Photoelectric Telescope are presented for the ellipsoidal variable 33 Tauri, and the magnetic Chemically Peculiar stars HD 50169 and HR 7786. We confirm that Hube's period of 2.975272 days for 33 Tau is correct. HD 50169 is a constant MCP star. HR 7786 is a large amplitude class member confirming Winzer's discovery, but its period is 8.5297 days. Its comparison star, HR 7721, a spectroscopic binary B7 V star, is variable with an amplitude of order 0.1mag, but of indeterminant period. In addition Hipparcos photometry of the comparison and check stars for early type stars whose photometry is being obtained with the FCAPT is reviewed to ascertain the stability of these stars.
We present differential uvby photometry of {theta} CrB obtained in 1994 and 1995, complemented by Balmer line spectroscopy. This star has been constant during this period, showing no short term periodic variability with an amplitude greater than 0.005mag., nor long term variations greater than 0.01mag. The lack of variability is associated with an inactive phase of the Be star, in which no emission features are present in the spectra. The only remarkable event observed was a fading episode on JD 2449779, with an amplitude of about 0.02 magnitudes in all bandpasses and duration of 0.2-0.3 days.
theta Tucanae (HR 139, V=6.11, A7 IV) is a binary with a delta Scuti primary that was the subject of several photometric monitoring campaigns during the 1970s and again in the 1990s. The data presented in this paper were collected during an observing campaign from mid-September to the end of October 1993 at ESO La Silla, Chile, using the simultaneous Stroemgren uvby photometer at the SAT telescope during 25 partial nights. We present a time series of 1432 four-colour extinction-corrected magnitudes in the SAT instrumental system. This collection of data forms a homogeneous and contiguous dataset, obtained in one single instrumental setup, at one single observing site using one single observing protocol, and with centralized data reduction.
