Bright Occultation Oct. 25 am Arizona to Delaware
New: 2005 Oct. 17
On Tuesday morning, October 25th, 8.3-mag. SAO 60082 near Castor will be occulted by the 24-km asteroid (390) Alma in a west- to-east path that will pass somewhere over the Washington, DC region. We need help from observers in and near the path to watch and try to time this relatively bright, easy to locate star so please mark your calendars and attempt it if it looks like it will be clear. Please let me know so we can coordinate coverage across the path, so that other mobile observers and I don't duplicate your chord. Copy your response to Derek Breit at breit_ideas@hotmail.com since I will probably be out of town most of the time from now until the event. He will update the coverage of the occultation on his Web site (see below) and will mark on that observers who have said that they will try the occultation. The star will be at high altitude and being so bright, observation even in light-polluted areas with lots of trees should be possible. I expect to be out of town from tomorrow afternoon until late Monday afternoon, Oct. 24, so I won't be able to do much organizing until then; please check your e-mail the evening of the 24th for any messages I may distribute about this bright event. The target star, also known as HIP 36157, is at J2000 RA 7h 26m 57.1s, Dec +31 deg. 45' 03", 1.6 deg. west of Castor (alpha Geminorum) and 0.5 deg. west of 5th-mag. rho Geminorum; a 7th-mag. star about 15' northwest of the target star will further simplify finding it. A list of stations for this occultation, listed by distance in km from the predicted central line, can be found on Derek Breit's Web site at http://www.poyntsource.com/BREIT_IDEAS/Alma.htm . Sorry, I don't have to to add hot links here, for them, go back to the main page and go into the Mid-Atlantic expedtions item that has these same links. In Breit's list, you can search for your, or your town's or observatory's, name to see just when the occultation is predicted for your area (that time should be accurate to within 15 seconds or so), the probability for having an occultation there, and the predicted Sun and star altitudes at the time. If your station is not in the list, send me your coordinates, or your street address, and we can add it; copy your message with this information to Derek Breit (see above) so he can add it to his Web site. Some fairly detailed maps of the path were added tonight by Steve Preston to his Web site at http://www.asteroidoccultation.com . That site also have many star charts of different scales to help locate the star. As you can see on Preston's Web site given above, the occultation path crosses North America from just south of Ensenada, Baja California, to Delaware. In northern Baja, the event will occur at 9:15 UT (2:15 am PDT); it then passes over s. Arizona between Phoenix and Tucson, passing closer to Phoenix. At 9:16 UT (3:16 am MDT), the path crosses, New Mexico, passing a little s. of Albuquerque. At 9:17 UT (4:17 am CDT), it passes over the Texas Panhandle and northern Oklahoma. At 9:18 UT, it crosses southern Missouri (near Springfield and Cape Girardeau) and the southernmost parts of Ill. and Indiana. At 9:19 UT (5:19 am EDT), it crosses northern Kentucky, going over Louisville and a little north of Lexington, and then over Huntington, WV. At 9:20 UT, the path passes over northern Virginia and the southern suburbs of Washington, DC, over southern Maryland, and southern Delaware. Of course, the path location for this small asteroid is uncertain, by more than a path-width, so the occultation could occur as far north as Phoenix, Albuquerque, and Baltimore. If an occultation occurs, there will be a 6-magnitude drop, to the asteroid's 15th mag. (most won't be able to see that, so the star will essentially appear to vanish, unless it's a close double) that will last only about 2 seconds for a central event (so video recording is preferred if it can be done; but a visual observation is better than NO observation!). The 47% sunlit Moon 18 deg. away shouldn't cause too much trouble. _____________________________________ David Dunham, 2005 October 16 pm phones home 301-474-4722; office 240-228-5609; cell 301-526-5590 BUT note above, I'll be out of the country and not reachable from Oct. 17 3 pm EDT until Oct. 24 6 pm EDT; I hope to have some access to my home e-mail, dunham@starpower.net