From: bcollins@utdallas.edu (Arlin B. Collins)
Newsgroups: sci.astro
Subject: S&T Weekly News Bulletin
Date: 17 Aug 92 03:03:33 GMT
Distribution: na
Organization: Univ. of Texas at Dallas

**** 
 SKY & TELESCOPE NEWS BULLETIN -- AUGUST 14, 1992
 
 YUCATAN NEWS 
 Today's issue of SCIENCE magazine carries a report that is big news for
 those in the impact biz. Using sensitive dating techniques, a team of
 scientists have finally determined an accurate date for a large impact
 feature buried beneath the Yucatan peninsula in Mexico. That date is
 64.98 million years, with an error of no more than 50,000 years. The
 result virtually certifies that the 100-mile-wide crater is indeed the
 cause of a tremendous extinction of life on Earth 65 million years ago.
 Moreover, the age of the rock sample tested is indistinguishable from
 that of a thick bed of impact ejecta "splashed" onto nearby Haiti. 
 
 PERSEIDS: A FIRST REPORT 
 A remarkably consistent picture of the 1992 Perseid meteor shower has
 emerged from early reports submitted by SKY & TELESCOPE's readers.
 Although a nearly full Moon compromised everyone's observations, the
 consensus seems to be that this year's shower was better than average.
 But it was not the meteor storm that some had hoped might occur as a
 precursor to the possible return of Comet Swift-Tuttle -- the source of
 the Perseids. Last year, for example, Japanese observers watched in
 amazement as Perseids flashed by at the rate of 300 per hour. 
 
 German amateur Mark Hardaker reports seeing more than two dozen
 Perseids brighter than 2nd magnitude in an hour at local midnight on
 August 12th, and more than 20 of them in the hour thereafter. John
 Bortle saw a similar number of Perseids soon afterward from his home in
 New York. According to Joseph Lynch, who described how to monitor
 meteors with radio equipment in the August issue of SKY & TELESCOPE,
 ham operators recorded the peak radio activity around 18 hours
 Universal time on August 11th, which was during daylight hours in North
 America. 
 
 NAKED-EYE SUNSPOT 
 Right now the sunspot count is moderate, with Caspar Hossfield
 reporting an index of 81 for the week ending August 12th. But numbers
 can be deceiving. Rick Krezewski called in to alert us of a huge
 naked-eye sunspot on the east side of the disk. Rick says the group has
 an unusually large and detailed penumbra, or skirt, around the darker
 interior region. If you do go looking for this sunspot, please observe
 safely and take the proper precautions. Use filters specially made for
 solar viewing, or a welder's glass of shade number 13 or 14. 
 
 -----THIS WEEK'S "SKY AT A GLANCE" 
 
 AUG 17 -- MON
 Venus and Jupiter are just 5 degrees apart and closing! See Planet
 Roundup. 
 
 AUG 18 -- TUE
 Saturn's brightest moon Titan can be seen in a small telescope four
 ring lengths west of the planet for the next couple nights. 
 
 AUG 19 -- WED
 Venus and Jupiter are 3 degrees apart. 
 
 AUG 20 -- THU
 Mercury is at greatest elongation, 18 degrees west of the Sun in the
 dawn. 
 
 AUG 21 -- FRI
 Last quarter Moon (exact at 6:01 a.m. Eastern daylight time). Before
 dawn look for the Pleiades close to the Moon. Binoculars help. Tomorrow
 before dawn, the Moon will be near Mars and Aldebaran. 
 
 AUG 22 -- SAT
 Venus and Jupiter in conjunction, only 1/3 degree or less apart! Scan
 for them with binoculars just above the horizon due west 30 minutes
 after sunset. Venus is the brighter one. 
 
 AUG 23 -- SUN
 Venus and Jupiter are still within 1 degree apart. 
 
 ----- THIS WEEK'S PLANET ROUNDUP
 
 MERCURY is very low in the east-northeast during dawn. Don't confuse it
 with Procyon to its right; Mercury is the one under Castor and Pollux.
 
 VENUS is barely above the western horizon in bright twilight shortly
 after sunset, close to fainter Jupiter. The two planets pass very near
 each other on the 22nd. Use binoculars! 
 
 MARS, in Taurus, rises around 12:30 a.m. and shines high in the east
 before dawn. It's a few degrees from similarly-colored Aldebaran, which
 is a bit fainter. 
 
 JUPITER is near Venus after sunset; see above. 
 
 SATURN shines in the southeast after darkness falls. It's higher in the
 south by midnight. 
 
 URANUS and NEPTUNE, 6th and 8th magnitude, respectively, are in the
 south after dark. 
 
 PLUTO is a 14th-magnitude speck getting low in the southwest after
 dusk. 
 
 -----
 SkyLine is provided by the publishers of "Sky & Telescope" magazine.
 It may not be used for profit. It is released via "go astroforum" on
 CompuServe, Friday afternoons.
-- 
Arlin B Collins     CompuServe:  INTERNET:bcollins@utdallas.edu   :-)