Prime Focus

The newsletter of the Tri-Valley Stargazers August 1997.
Translated (roughly) from postscript into HTML for your browsing and downloading pleasure.
This satellite image shows the extent of light pollution across the continental United States. It is a composite of shots taken by the Defense Meteorological Satellite Program (DMSP) net work. Reproduction is courtesy of the International Dark-Sky Association website.

August general meeting
Club news notes
Star parties
What's Up in August
Comet Comments
Library Survey
Membership application

TVS presents

What: Preserving dark skies
When: August 15, 1997
Who: Jack Sales, International Dark-Sky Association
Where: Unitarian Universalist Church in Livermore, 1893 N. Vasco Rd.

Jack Sales is more than an amateur astronomer and Sacramento Valley Astronomical Association board member. He is also the founder of the California chapter of the International Dark-Sky Association. Through Cal-IDA he works to reduce light pollution statewide.

According to Jack, urban observers should be able to capture about 2000 stars on an ideal seeing night. Instead, they are fortunate to pick out about 100. He declares that loss intolerable. "The dark skies, the deep-space objects like comets, are part of our natural environment. We should care about losing them; we lose something of ourselves when we lose that connection."

IDA's primary goals are: to halt the spread of light pollution, to attempt to reverse the negative environmental impacts already caused by light pollution, and to protect existing dark-sky regions to the maximum degree possible. Secondarily, the group hopes to educate the public, particularly public officials, about alternative lighting programs so that suburbs and cities can begin to reclaim their night skies.

Club News Notes for August

In memoriam

It is with deep sadness that we report the passing of two astronomers who made significant contributions to celestial science. Last month our field lost Eugene Shoemaker, co-discoverer of Comet Shoemaker-Levy 9; and Stephen Kufeld, manufacturer of the popular Telrad spotter scope. Gene's demise occurred following an automobile accident in central Australia. His wife Carolyn Shoemaker sustained broken ribs and thoracic injuries in the crash, but is recovering from her injuries. Steve's immediate cause of death was not available as this issue went to press.

Gene and Carolyn Shoemaker and their colleague David Levy jointly discovered "their" comet some 16 months before it was to inspire intense observation by shredding into a succession of fragments that impacted Jupiter individually. Gene and Carolyn were on an annual expedition to study terrestrial impact crater sites Down Under when he was fatally injured on July 18th. Together the Shoemakers shot more than 25,000 plates of the sky from Palomar Observatory. In addition to their comet finds and recoveries, they can claim the identification of over 800 asteroids. Their work on the mechanics of comet/asteroid impacts and the classification of Earth-cross ing objects also brought them international recognition.

Steve Kufeld improved amateur astronomy by perfecting the Telrad system for targeting an astronomical object with a bulls-eye pattern. His devise can be seen in use at every TVS star party. Steve's brother Ron Kufeld informed AANC officers that Steve succumbed on July 1st. Production of the Telrad has been briefly suspended, but Ron expects it to resume once Steve's affairs are set in order.

Condolence messages can be forwarded to the families of both men. To send your regards, contact the respective parties below. Carolyn Shoemaker c/o Cal Tech Astronomy Department Mail Stop 105-24 Caltech Pasadena, CA 91125

Ron Kufeld c/o Eagle Optics 716 S. Whitney Way Madison, WI 53711

Library update
Pages 5 and 6 of this issue are a tear-and-mail library survey. This is your opportunity to select the books, magazine subscriptions, videos, audio cassettes, or slides you have always wanted, and TVS will pay the bill.

Club librarian Chris Cody is eager to hear what members would like in the way of upgraded holdings. He is also creating the software that will allow the catalog to be fully on line.

To respond to the survey, simply complete it, and tear that page away from the corner staple. Fold the sheet in half, staple or taped closed, and attach a 32-cent stamp in the corner indicating postage. Then just drop it in the closest post box, and it's on its way to Chris.

Buck up
Treasurer Gene Nassar reports that our financial condition is excellent. The precise details are:
Checking account $6,223.76
Money market $1,213.25 CD $3,167.22
The CD holds Sky Shack key deposits, which are refundable upon key return.

President Dave Anderson (510) 661-4249
Secretary Bill Burnap (510 ) 449-4552
Vice President Chuck Grant (510) 449-1500
Treasurer Gene Nassar (510) 462-7843
Observatory Director Chuck Grant (510) 449-1500
Librarian Chris Cody (707) 747-6550
Eyes on the Skies BBS Mike Rushford
Web Site
Editor Alane Alchorn (510) 455-9464 (510 ) 455-9466 fax
Meeting Location Unitarian Universalist Church in Livermore 1893 N. Vasco Rd. 3/4 mile north of I-580

Membership: 186
Alane Alchorn, Dennis Beckley, Rich Combs, Rich Green, Russ Kirk, Dave Rodrigues, Debbie Scherrer, Al Smith, Dave Sworin, Jim Zumstein

Tri-Valley Stargazers

P.O. Box 2467
Livermore, CA 94551

August Star parties

August 22-24 Yosemite star party Contact Dave Rodrigues (510) 483-9191 Please see note below regarding the Yosemite potluck.

August 23 Sky Shack observatory and dark site open house, meet at Mines and Tesla Roads at 7:00 PM

September 6 Sycamore Grove Park Livermore 8:30 PM

September 20 Sky Shack observatory and dark site open house, meet at Mines and Tesla Roads at 7:00 PM Final open house for 1997.

For information on these or any other star parties refer to the club star parties webpage.

---- Yosemite potluck : The club needs a potluck coordinator for the star party weekend at Yosemite. If you are planning to attend, and can help assign food for different families to bring, please contact Dave Rodrigues at (510) 483-9191. You will not be responsible for cooking or providing any special contribution beyond your fair share. Thanks!

What's Up in August

by Dave Anderson

23 Sat Star Party at Glacier Point, Yosemite.
August 1997
1 Fri Io's shadow transits Jupiter 11:08 PM to 1:27 AM Io transits 11:19 PM to 1:38 AM PDT.
2 Sat Star party at Sycamore Grove Park (Livermore Park District) 8:00 PM (Wetmore Rd. entrance near Holmes St.).
Star-B-Que at Fremont Peak (South of Gilroy) 5:00 PM
Mars 1.7° north of Spica.
3 Sun New Moon 1:14 AM Excellent weekend for observing.
Mercury at greatest eastern elongation (27° ) in evening sky.
End of Mars Pathfinder's primary mission.
5 Tue Mercury 1.0° south of Moon (occulted in Greenland). Venus nearby.
6 Wed Ganymede eclipsed by Jupiter's shadow 1:35 AM
8 Fri Galileo explores Jupiter's magnetot ail.
9 Sat Jupiter at opposition (mag -2.8, apparent diameter 48").
Mars 4° south of Moon.
Io's shadow transits Jupiter 1:03 to 3:21 AM Io transits 1:03 to 3:22 AM Io occulted 10:19 PM, reappears from eclipse 12:37 AM
Europa transits until 10:57 PM; shadow transits until 11:00 PM
10 Sun Callisto reappears from ooccultation by Jupiter 8:47 PM
Io transits until 9:47 ; Io's shadow until 9:50 PM
11 Mon First Quarter Moon 5:42 AM
Delta Cephei at maximum 2:22 AM Variable rises to mag. 3.5 from 4.4 in about 1.5 days. (Period is 5.366341 days). Compare Zeta Cephei (mag. 3.35) and Epsilon Cephei (mag. 4.2).
12 Tue Perseid meteor shower peak around 11 AM
15 Fri Tri-Valley Stargazers meeting 7:30 PM Unitarian Universalist Church of Livermore, 1893 N. Vasco Road, Livermore. (3/4 mile north of I-580).
16 Sat Io transits Jupiter 2:47 AM; Io's shadow transits 2:58 AM
Ganymede transits Jupiter until 10:31 ; Ganymede's shadow until 11:19 PM
Europa transits 10:20 PM to 1:10 AM; Europa's shadow transits 10:43 PM to 1:34 AM
Io occulted 12:02 AM, reappears from ooccultation 2:32 AM
17 Sun Jupiter 4° south of Moon.
Io transits 9:13 to 11:32 ; shadow transits 9:27 to 11:45 PM
18 Mon TVS Planning Meeting 7:00 PM Round Table Pizza, 1540 First St., Livermore (in Orchard Supply/Longs/Safeway shopping center).
Full Moon 3:55 AM
Io reappears from eclipse by Jupiter's shadow 9:00 PM
Callisto transits 9:37 PM to 2:25 AM Callisto's shadow transits 11:58 PM
21 Thu Saturn 0.008 ° north of Moon (occulted in central Africa).
22 Fri Star Party at Glacier Point, Yosemite.
Ganymede transits Jupiter 10:10 PM to 1:49 AM; shadow transits 11:41 PM to 3:20 AM
Europa transits 12:34 to 3:24 AM; shadow transits 1:18 to 4:09 AM
Io occulted 1:46 AM, reappears from eclipse 4:26 AM
24 Sun Last Quarter Moon 7:23 PM
Asteroid 19 Fortuna (mag 9.6) at opposition.
Io transits Jupiter 10:58 PM to 1:16 AM; Io's shadow 11:22 PM to 1:40 AM
25 Mon Aldebaran 0.3° south of Moon (occulted in daylight).
Europa reappears from eclipse by Jupiter's shadow 10:47 PM
Io reappears from eclipse 10:55 PM
29 Fri Asteroid 1 Ceres (mag 7.7) at opposition.
30 Sat Excellent weekend for observing: No Moon until 4:30 AM
31 Sun Ganymede transits Jupiter 1:31 ; shadow transits 3:43 AM
Europa transits 2:49 ; shadow transits 3:53 AM
Io occulted 3:31 AM

September 1997
1 Mon Labor Day.
New Moon 4:52 PM PDT.
Partial solar eclipse in Australia.
Io transits Jupiter 12:43 to 3:01 AM; shadow transits 1:17 to 3:35 AM
Europa occulted by Jupiter 9:19 PM, reappears from eclipse 1:25 AM
Io occulted 9:57 PM, reappears from eclipse 12:49 AM
2 Tue Moon at farthest apogee of year (40 6,479 km).
Io transits Jupiter until 9:28 PM; shadow transits until 10:04 PM
3 Wed Europa's shadow transits Jupiter until 8:01 PM
Ganymede reappears from eclipse 9:15 PM
4 Thu Asteroid 1 Ceres (mag 7.7) at opposition.
Callisto's shadow transits Jupiter until 11:01 PM

Some Summertime Deep-Sky Objects

M5 One of the best globular clusters, in Serpens (Caput).
M13 The Great Hercules Cluster! Look for the mag. 12 galaxy NGC 6207 in the same field.
M92 Another fine globular cluster in Hercules, often overlooked.
M4 & M80 Two globular clusters near Antares in Scorpius.
M6 & M7 Two fine open clusters near the stinger of Scorpius.
M22 Another great globular cluster, in Sagittarius.
M8, M20 & M17 The Lagoon, Trifid, and Swan Nebulae in Sagittarius!
M11 The Wild Duck Cluster in Scutum! Perhaps the richest of all open clusters.
M57 The Ring Nebula, a famous planetary nebula in Lyra.
M27 The Dumbbell Nebula, a superb planetary in Vulpecula!
NGC6960/92/95 The Veil Nebula in Cygnus. A large supernova remnant. (Try an OIII filter).
NGC7000 The North America Nebula near Deneb. Fine in binoculars under dark skies.

Comet Comments

by Don Machholtz


C/1995 O1 (Hale-Bopp)
Date (00 UT) R.A. (2000) Dec El Sky Mag
08-05 07h24.3 m -14° 28' 39° M 4.7
08-10 07h29.6 m -16° 21' 42° M 4.9
08-15 07h34.7 m -18° 16' 45° M 5.0
08-20 07h39.5 m -20° 13' 47° M 5.1
08-25 07h44.1 m -22° 11' 50° M 5.3
08-30 07h48.4 m -24° 11' 52° M 5.4
09-04 07h52.4 m -26° 12' 55° M 5.5
09-09 07h56.2 m -28° 15' 58° M 5.6

C/1997 N1 (Tabur)
Date (00 UT) R.A. (2000) Dec El Sky Mag
08-05 08h42.8 m -02° 21' 20° M 6.2
08-10 09h10.9 m +03° 24' 12° M 5.7
08-15 09h37.7 m +09° 31' M 5.5
08-20 10h04.2 m +15° 35' E 5.8
08-25 10h31.1 m +21° 08' 11° E 6.4
08-30 10h59.0 m +25° 56' 18° E 7.1
09-04 11h28.5 m +29° 58' 24° E 7.8
09-09 11h59.7 m +33° 15' 30° E 8.4

A new comet has been recently discovered in the southern sky. Meanwhile, Comet Hale-Bopp continues to dim in the southern sky. Both comets will be briefly visible to many Northern Hemisphere observers in a few months.

The new comet was discovered by Vello Tabur of Australia on July 2. He used an 8-inch f/4.7 reflector to find the tenth magnitude object, which was situated in the morning sky, far south of the sun and out of view of Northern Hemisphere observers. It was Tabur who had made the last visual discovery--nearly a year ago. Comet Tabur (C/1997 N1) will appear in the evening sky for northern observers in early September.

The solar-orbiting satellite SOHO has picked up five additional small comets as they headed toward the sun. Most of the 17 comets found by the satellite belong to the Kreutz Sungrazing Group, all were faint and seen only by the satellite. Most disappeared as they rounded the sun.

COMET HUNTING NOTES: With Tabur's find, six of the last seven visually-discovered comets have been found south of the celestial equator; and 14 of the last 17 visually-discovered comets have been found in the morning sky.

Orbital Elements
Object: Hale-Bopp Tabur
Peri. Date: 1997 04 01.13800 1997 08 15.24722
Peri. Dist (AU): 0.9141 405 AU 0.3832 189 AU
Arg/Peri (2000): 130.58915 deg. 345.44824 deg.
Asc. Node (2000): 282.47069 deg. 148.24000 deg
Incl (2000): 089.42943 deg. 086.40198 deg
Eccen: 0.9951172 1.0
Orbital Period: ~2500 years Long Period?
Ref: MPC 29568 IAU Cir. 6694
Epoch: 1997 06 01 1997 08 15
Absol. Mag/"n": -1.0/4.0 9.0/4.0

Survey of Library Needs

In order to make the TVS library useful and attractive to members we would like your input on our holdings; additionally we would like your input on future acquisitions. Please take a few minutes to complete the following survey. Please place it in the survey box or give it to Chris Cody at the monthly meeting or mail it to us.

Circle your selections.

1. Number of times you have used the library in the last six months
5 4 3 2 1 0

Do you use the library's Frequently Never
Books5 4 3 2 1 0
Magazines5 4 3 2 1 0
Videos5 4 3 2 1 0
Audio Tapes5 4 3 2 1 0
Computer Programs5 4 3 2 1 0

Types of resources desired Strongly Not at all
General 543210
Textbooks 543210
History 543210
Biography 543210
Solar System 543210
Space exploration 543210
Deep Sky 543210
History 543210
Books on Tape 543210
Observation aides 543210
Programs Planetarium 543210
Ephemeris 543210
Solar System 543210
Other Books (please list)___________________________________
Other Videos ______________________________________________
Other Audio Tapes___________________________________________

4. Would an on-line catalog be useful to you?

5. Have you contacted the library web page? Y N

How valuable to you is the: Very Not at all
Periodical page 543210
Reference page 543210
Interlibrary loan page 543210
What sections would you like to see on the library web page? ___________

7. Is the collection easy to search Y N

8. Do you have a CD ROM on your computer? Y N

What is your interest in CD ROM
images? 543210
programs? 543210

Mail to Chris Cody, P.O. Box 142, Benicia, Ca 94510-0142 or bring to the next meeting.

Tri-Valley Stargazers Membership/Renewal Application

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