The MACHO project is engaged in an ongoing, time resolved survey of stars in the Magellanic Clouds and galactic bulge to search for microlensing by intervening compact objects

Real-time detection of microlensing has moved from proof of concept in 1994 (Udalski et al.l994a, Alcock et al.1994) to a steady stream of events this year. Global dissemination of these events by the MACHO and OGLE collaborations has made possible intensive photometric and spectroscopic follow up from widely dispersed sites confirming the microlensing hypothesis (Benetti 1995). Improved photometry and increased temporal resolution from follow up observations greatly increases the possibility of detecting deviations from the standard point-source, point-lens, inertial motion microlensing model. These deviations are crucial in understanding individual lensing systems by breaking the degeneracy between lens mass, position and velocity. We report here on GM AN (Global Microlensing Alert Network), the coordinated follow up of MACHO alerts. 221 C. S. Kochanek andJ. N. Hewitt (eds), Astrophysical Applications of Gravitational Lensing, 221-226. © 1996 IAU. Printed in the Netherlands. available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0074180900231331 Downloaded from https://www.cambridge.org/core. IP address: 54.70.40.11, on 01 Aug 2018 at 19:36:20, subject to the Cambridge Core terms of use, 222 M.R. PRATT ET AL.