Bolivana occ'n observed; spectacular Thurs. lunar event; others
Updated: 2001 Dec. 19Asteroidal Occultation observed in DC area, maybe Alabama; Spectacular lunar occultation & Graze, tau 2 Aquarii, Thurs. evening 1. An 11th-mag. star in Orion was occulted by (712) Boliviana around 10:30 pm EST yesterday evening (Dec. 19 around 3:30 UT) with the updated path crossing central Scandinavia, Newfoundland to Boston to New York City to n.w. of Washington, DC to Memphis and on to Austin, Texas, n. Mexico to just n. of La Paz, B.C. But the actual path shifted south half a path-width, into heavily-populated areas of Texas and the Northeastern USA, while the time correction was small, only about 0.1 minute late, all of this relative to Steve Preston's prediction distributed yesterday. In addition, I got to test my new Supercircuits PC164C camera, and it is certainly a good buy, nearly as sensitive as the Watec 902H. See below for more. 2. A spectacular occultation and graze will occur Thursday evening, Dec. 20, shortly before 8 pm EST, with 4th-mag. tau 2 Aquarii and the 32% sunlit Moon, visible from the eastern half of North America, with the southern-limit dark-limb graze near the coast from near Tallahassee, FL to Kitty Hawk, NC. Times and the s. limit are shown on p. 118 of the Jan. 2001 issue of Sky and Telescope, and times for dozens of cities are now on the IOTA Web site. The occultation can be seen with binoculars or accurately recorded with most camcorders WITHOUT the need for a telescope. The last 3 asteroidal occultations below all occur on Dec. 21 UT. More information about them can be found on the asteroidal occultation page of IOTA's main site at http://www.lunar-occultations.com/iota and at Steve Preston's Web site that can be linked to from there. 3. A 10.6-mag. star at J2000 RA 2h 40m 46.4s, Dec. +36 deg. 26' 48" will be occulted by (117) Lomia at 3:14 UT in Thunder Bay, Ont.; 3:15 at Duluth and Minneapolis, MN; Omaha at s. limit at 3:16 UT; w. Kansas at 3:17; Okla. & Texas panhandles at 3:18; 3:19 UT over Alamogordo & Las Cruces, NM and El Paso, TX; and 3:20-3:21, over northwestern Mexico; also, over e. Romania, w. Ukraine, central Poland, and Denmark earlier. 4. A 10.6-mag. star at J2000 RA 7h 58m 18.8s, Dec. +3 deg. 4' 59" will be occulted by (242) Kriemhild at 11:16 UT across North Carolina, 11:17 UT over Chattanooga, TN to northern Mississippi; 11:18 in souther Arkansas, and just north of Dallas-Ft. Worth, TX; at 11:19 near Abilene and Lubbock, TX; just s. of El Paso, TX at 11:20; then across northwestern Mexico. 5. A 10.7-mag. star at J2000 RA 4h 56' 56.6", Dec. +24 deg. 9' 19" over east & south Ukraine at 21:52-21:53; northernmost Romania at 21:54; Hungary (including Budapest) at 21:55; southern Austria at 21:56; northern Italy, just north of Milan and southern Switzerland at 21:57; southern France at 21:57-21:58 (just s. of Geneva to near Bordeaux); and northwestern Spain at 21:59-22:00. _______________________________________________________________________ 1. Bob Bolster timed an 11-second occultation using a C14 at Alexandria, Virginia; the D was at 3:30:27.1 and the R was at 3:30:38.3 UT. This was only about 6 seconds later than the central time for him predicted by Steve Preston distributed yesterday; you can consult his chart for the closest approach time at your location, and add 0.1 minute to it to get what it was for you. But his observation indicated that the path shifted at least half a path-width south of Preston's prediction. Dennis DiCicco recorded the event with a 16-inch near the predicted central line in Sudbury, Mass., and apparently had no occultation. Unfortunately, other observers in the Boston area, where an occultation surely occurred, were clouded out shortly before the event. I also recorded the appulse from a rather dark site a few miles southwest of Hancock, Maryland, and also apparently had no occultation, although there were a few dimmings that could have been seeing events. I will calculate later whether DiCicco or I was closer to the actual path; in any case, both of us can review our recordings at the appropriate time to see if a short occultation may have occurred. Joe Sedlak also apparently saw the occultation from Glen Dale, Maryland (rather close to Bolster's chord), but he did not get a good timing since the relatively small magnitude drop was not obvious to him with a 10-inch Dobsonian. David Nance in Madison, Alabama, also south of Preston's southern limit a short distance, timed a short dimming, only about a second, at the right time, maybe near the southern limit? He used a C-8 at 160x. I recorded the event easily with a Watec 902H camera, C-8, and f3.3 focal reducing lens. It showed the 11th-mag. objects well, and in similarly dark skies, I'm sure it can easily record 11.5-mag. occultations, and 12th-mag. marginally. I also tried the new Supercircuits PC164C camera, which is much cheaper, as noted in previous messages, at $130, and it also showed Boliviana and the target star (seeing them separate before and after the appulse was interesting). If you have a Schmidt-Cass, I highly recommend using these cameras with an f3.3 focal reducing lens to get a larger field of view. I would say that the PC164C is only a little less sensitive than the Watec 902H, by only a few tenths of a magnitude, and that's only probably because the Watec chip is 1/2-inch versus 1/3-inch for the PC164C (so the star's seeing disk is spread out over more pixels on the PC164C). More information, including some images, will be posted here, either Friday but more likely on January 2nd. Below is the prediction information from yesterday: The updated path for the occultation of 11.0-mag. TYC 0717 0435 by the 127-km C-type asteroid (712) Boliviana, occurring at 10:30 pm EST this evening (Tuesday, Dec. 18, 2001), has shifted south about 1.3 path-widths from Goffin's nominal path shown on p. 119 of the Feb. 2001 issue of Sky and Telescope, according to Steven Preston's calculations with recent accurate astrometry for this asteroid that is as bright as the star. The path crosses n.w. Russia and central Finland at 3:21 UT (Dec. 19 UT); then central Sweden and Norway; n. and w. Newfoundland at 3:27 UT; Prince Edward Island, n.w. Nova Scotia and s.e. New Brunswick at 3:28 UT; coast of Maine at 3:29; then s. NH and most of Massachusetts with Boston just inside the s. limit; then most of Connecticut and s. New York, with Manhattan at the s. limit; 3:30 UT (10:30 pm tonight EST) over n. New Jersey, e. and s. Pennsylvania & w. Maryland with Philadelphia and Baltimore just s. of the s. limit; West Virginia at 3:31 UT, then eastern Kentucky and much of Tennessee (Nashville, and Memphis at n. limit) at 3:32; n. Mississippi and s. Arkansas; n.w. Louisiana (Shreveport) at 3:33 UT; then over eastern Texas (Nacogdoches) and just before 3:34, Austin inside and San Antonio outside the s. limit; then over n. Mexico, and just n. of La Paz, Baja California at 3:35 UT. Observers in and near this path should be ready to time a possible occultation, which would last up to 14 seconds with a 0.7-magnitude drop. The star is at J2000 RA 6h 04m 56.5s, Dec. +8 deg. 50' 59" in Orion about 3 deg. east and a little north of Betelgeuse, 1 deg. southeast of 4th-mag. mu Orionis, and about 8' south and a little west of a star of about mag. 7.5. A finder chart can be found in the table of the asteroidal occultation page of IOTA's Web site at http://www.lunar-occultations.com that also has links to Steve Preston's site with maps and other details of the event. This is a good event for the Watec and PC164C sensitive videocameras. _______________________________________________________________________ David Dunham, early 2001 Dec. 18 Phone home 301-474-4722; office 240-228-5609; car 301-526-5590.