STROMGREN UVBY PHOTOMETRY OF THE MAGNETIC CHEMICALLY PECULIAR STARS HR-1643, THETA-AUR, 49-CAM, AND HR-3724

Differential Stromgren uvby photometric observations from the Four Col lege Automated Photoelectric Telescope of four magnetic chemically pec uliar stars are used to refine rotational periods and to define the sh apes of the light curves. HR 1643 (P=2.73475 d) shows large in-phase v ariability in all four magnitudes. theta Aur (P=3.6188 d) exhibits lar ge amplitude variations with two components contributing to the minima . For 49 Cam (P=4.28679 d), we probably are observing both polar regio ns and much of the surface. The values for HR 3724 (P=33.984 d) confir m Wolff's result that the main variability is in v.