------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 2622 2010 Feb 06 15.20UT 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 Backup: gmh@wdcc1.bnsc.rl.ac.uk WORLD WIDE WEB http://www.theastronomer.org ------------------------------------------------------------------- U SCORPII Bradley Schaefer continues (cf TA E-Circular 2621): Use the list below to select which mornings will have U Sco observable for your location for times within 5 hours of the quoted eclipse centre times. (We must have observations around 5 hours of so on either side of eclipse so as to know the un-eclipsed level.) When U Sco rises high enough, start taking your normal time series and just keep at this until dawn makes you stop. Choose the shortest reasonable exposure time such that U Sco and one of the comparison stars (preferably COMP) are not saturated. If you have a V-filter then use it (R-band is the only other option to use). If you need more signal or do not have a V or R filter, then simply run without any filter. After dawn, process your images (bias subtract, flat field...) in the usual way. Extract the magnitude of U Sco with aperture photometry in comparison with one or more of the stated comparison stars (preferably COMP). Send these magnitudes to myself (schaefer@lsu.edu) with a copy to the TA Editor. Here is a table with all the eclipse times from now to early March: JD mid-eclipse UTmid UT date Where Visible 2455232.571 1:43 5-Feb South Africa 2455233.802 7:15 6-Feb Florida, Chile 2455235.032 12:47 7-Feb Calif, Hawaii 2455236.263 18:18 8-Feb NZ, Australia 2455237.493 23:50 9-Feb South Africa 2455238.724 5:22 11-Feb Chile 2455239.954 10:54 12-Feb Florida-Calif 2455241.185 16:26 13-Feb Hawaii, NZ, Australia 2455242.416 21:58 14-Feb Aus-SA 2455243.646 3:30 16-Feb South Africa 2455244.877 9:02 17-Feb Florida-Calif 2455246.107 14:34 18-Feb Hawaii, NZ 2455247.338 20:06 19-Feb Aus-SA 2455248.568 1:38 21-Feb South Africa 2455249.799 7:10 22-Feb Florida, Chile 2455251.029 12:42 23-Feb Calif, Hawaii 2455252.260 18:14 24-Feb NZ, Australia 2455253.491 23:46 25-Feb Aus-SA 2455254.721 5:18 27-Feb Chile 2455255.952 10:50 28-Feb Florida-Calif 2455257.182 16:22 1-Mar Hawaii, NZ, Australia 2455258.413 21:54 2-Mar Aus-SA 2455259.643 3:26 4-Mar South Africa 2455260.874 8:58 5-Mar Florida-Calif 2455262.104 14:30 6-Mar Hawaii, NZ 2455263.335 20:02 7-Mar Australia 2455264.565 1:34 9-Mar South Africa 2455265.796 7:06 10-Mar Florida, Chile 2455267.027 12:38 11-Mar Calif, Hawaii The eclipses should be just starting as shallow events now, and after early March then U Sco will likely have a sudden drop in brightness making it hard to get eclipses. This is easy, this is exciting, this is big-time science, and only the amateurs with CCD can do this! Editor: So we can track responses please send an e-mail confirming your plans. Finder charts can be obtained via e-mail from the editor on request. Guy M Hurst