Optical/Infrared/X-ray Observations in 1981

W. Lewin, L. Cominsky and A. Lawrence, Massachusetts Institute of Technology, communicate: "M. Oda and the Hakucho Team have agreed to make time available on the Hakucho x-ray satellite for simultaneous optical, infrared and radio observations of x-ray burst sources and transients during 1981. M.I.T. will coordinate the observations. A substantial fraction of the time from Apr. to Sept. will be dedicated to the coordinated observations. Exact dates will depend on the responses we receive from interested observers and will be announced at a later date. The candidate targets will be chosen from the sources which will be then burst-active. Possible targets will include the bursters MXB 1735-44 (IAUC 3230), MXB 1659-29 (IAUC 3190, 3229) and MXB 1636-53 (from which 40 optical bursts were detected in 1979 and 1980, ten of these seen at x-ray wavelengths; cf. IAUC 3399). During July-Sept., we will concentrate on infrared/radio/x-ray observations of the Rapid Burster MXB 1730-335 (cf. IAUC 3520), which was not active during x-ray observations made during 1980 Apr.-May or Aug.-Sept. Participation by optical observers with time on large telescopes (at least 1.5 m aperture) is invited during Apr.-June. Infrared and radio observers are encouraged to participate during July-Sept. (cf. IAUC 3344, 3428). Astronomers who are interested should contact us (telephone 617-253-5827 or 617-253-7530, telex 92-1473 MIT CAM or TWX 710-320-0058 MIT CAM)."