Occultations by three asteroids Memorial Day Weekend - Updated 2006 May 26
Accuweather forecast good for 3 Memorial Day weekend asteroidal occultations
We need your help to observe this Memorial Day weekend's asteroidal occultations; the Accuweather forecast is good, with just scattered cirrus forecast, for all three of them. We will not have an expedition from the DC area for the occultation of an 11th-mag. star by the small (predicted 19km) asteroid (540) Rosamunde on Saturday evening, but I hope that some observers in North Carolina, especially in the areas where the path is expected near Salisbury, Sanford, Fayetteville, and Jacksonville, will try to observe it. The target star is at J2000 RA 16h 18m 39.0s, Dec -13 deg. 56' 26" in northwestern Scorpius 2 deg. s.s.w. of 5th-mag. chi Scorpii and about 40' s.s.w. of a pair of 7th-mag. stars. See below for links to Web sites that have detailed star charts, interactive detailed path maps, and station lists for these events. Please let me know your plans to observe the other two occultations so we can coordinate coverage of the paths, to try to get the best coverage across the path to better measure the sizes and shapes of Hertha and Isara. Mobile observers don't want to duplicate your observation but rather want to fill in gaps of the fixed-site coverage. The occultation of an 11.8-mag. star in Cancer by the 79-km asteroid (135) Hertha will be visible from Washington DC, n. Virginia, all of Maryland except the n.e. part, s. Delaware, s.w. Penn, & n.e. Ohio. The star is at J2000 RA 8h 59m 42.1s, Dec +17 deg. 34' 05", about halfway between 68 and FZ Cancri (which is at the same Dec., with RA about 15m greater than that of 4th-mag. delta Cancri = Asellus Australis s.e. of the Praesepe cluster). The altitude in the Washington, DC area is 16 deg. in the west- northwest, which will make it difficult to see from locations looking over the light domes of Washington or Baltimore and conditions will need to be good to see it in other areas, too. Nevertheless, it's worth a try, especially if you have a PC164C video camera and 8-inch or larger scope. Conditions are better towards the northwest, with altitude 20 deg. in n.e. Ohio, so tentatively I'm planning an expedition to go there rather than observe from home; that also gives a chance to observe the bright occultation, of 9.7-mag. SAO 140367 by the 28-km asteroid (364) Isara whose path crosses northern Ohio, northern Penn., and s.e. New York, near New Paltz and Kingston with that occultation occurring 3h 22m after the Hertha event. SAO 140367 = TYC 55840062 (or TYC 5584- 00062-1 in full) is at J2000 RA 15h 11m 18.2s, Dec -10 deg. 5' 53" 1.5 deg. west-southwest of beta Librae (Zubeneschamali). For such an expedition, I would leave Greenbelt early Sun. afternoon, stay at a motel overnight in n.e. Ohio, then return Monday afternoon. Tentatively I would plan the observations from sites near the north- south Ohio Hwy 534 north and south of Newton Falls. But this plan might be changed depending on the more accurate Clear Sky Clock forecasts that will become available starting tomorrow (Friday) afternoon. When I try to print Steve Preston's finder charts from his Web site, large parts of the charts are missed (clipped). To facilitate viewing and printing the full charts, I've put them in this power point file; I've annotated a few of them as well. Station lists indicating planned coverage will be distributed during the weekend, once I learn some of your plans. We will be concentrating on the asteroidal occultations described above and thus will not try the lunar grazing occultations in southern Virginia the same (Sunday) evening. _____________ Asteroidal Occultations Memorial Day Weekend, 2006 dur. Ap. Date Day EDT Star Mag Asteroid dmag s in. Location May 27 Sat 22:49 2UC26908898 11.2 Rosamunde 1.9 2 7 N. Carolina May 28 Sun 23:17 2UC38072338 11.8 Hertha 2.3 3 8 PA,MD,DC,nVA May 29 Mon 2:39 SAO 140367 9.7 Isara 3.8 3 4 seNY,nPA,nOH Updated paths, and often detailed finder charts, can be found at Steve Preston's Web site. Very detailed maps for these events can often be found on Derek Breit's interactive Web page that links to the very detailed maps and satellite imagery of maps.google.com with overlays of the occultation paths. Derek already has these for the Memorial Day weekend asteroidal occultations and for the July 20th Alcyone graze; Charlie Ridgway used to provide these. For many of these events, lists of stations sorted by distance from the updated central line are posted on Derek Breit's Web site. You can search for your name, city, or observatory by editing the list and searching for these items. If your station is not in that list, please let me and Derek, breit_ideas@hotmail.com , know so that you can be added to future lists. _____________________________________ David Dunham, 2006 May 26 pm Phones home 301-474-4722; office 240-228-5609; car 301-526-5590 emails dunham@starpower.net or office david.dunham@jhuapl.edu