------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 1542 2000 Jly 15 14.30UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074 INTERNET: GUY@TAHQ.DEMON.CO.UK GMH at AST.STAR.RL.AC.UK WORLD WIDE WEB http://www.demon.co.uk/astronomer ------------------------------------------------------------------- GAMMA RAY BURSTERS On Wednesday July 12, the editor spent the day at the University of Hertfordshire, Hatfield Campus with Nial Tanvir and various students to discuss our future strategy with regard to the above objects. A brief framework to our plans was drawn up but at this stage I need to establish the names of those observers who may be interested in joining the group. Although some alerts continue from other satellites, most messages will be expected from HETE although its launch has again been delayed until at least August. However we should use the interim period to practice techniques and to liaise closely with the AAVSO who already have some experience in such matters. In this respect the recent meeting in Huntsville proved invaluable in giving us initial guidance on the main objective which is to record the optical afterglows of such objects. The Astronomer Group intends to take a lead in this important area and Nial will be giving a talk at the forthcoming BAA AGM to be held on October 7. As a guide to those considering this work, we expect there will be a need to respond extremely fast to alerts because the possible optical counterpart can fade extremely quickly. Ideally observations are needed within six hours and we might expect to record some around magnitude 15 or perhaps fainter. The need is for imaging by either photography or, preferably, with CCDs but Nial's view is that filters are not needed initially as the prime objective is to go as faint as possible and to carry out immediate and accurate astrometry on any objects not on older images such as those from the Palomar Sky Survey. We will, in due course, explore possible use of filters in follow up work. I intend to issue alerts via these circulars but in addition will consider the resurrection of a telephone 'cable' service just for this category. Could I please ask potential TA observers, wherever in the world they are based, to e-mail me as soon as possible with confirmation they wish to participate and give their approximate latitude and longitude, telescope and CCD details. Any early views on our approach will also be welcomed. Guy M Hurst