Prime Focus

The newsletter of the Tri-Valley Stargazers October 1997.
Translated (roughly) from postscript into HTML for your browsing and downloading pleasure.

Although extrasolar planets may not be rocky and mountainous, like this portion of the Caloris Basin on Mercury, space-based observatories may one day transmit their images to Earth. (Photo credit : Mariner 10 space craft, NASA)


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

TVS presents

What: Planet Quest: The Epic Discovery of Alien Solar Systems
When: October 17, 1997
Who: You and your family
Ken Croswell, Ph.D.
Where: Unitarian Universalist Church in Livermore, 1893 N. Vasco Rd.

Dr. Ken Croswell earned his doctorate in astronomy from Harvard University, and is the author of two books. His first was the highly-aclaimed The Alchemy of the
(a finalist for the 1995 Los Angeles Times Book Prize), and his newest offering is entitled Planet Quest .

In a colorful slide show, Dr. Croswell will speak about planet-hunting, and the scientists who seek to prove the existence of alien solar systems. In Planet Quest , he suscintly defines the essential features of our own solar system, and then recounts stories of the discovery of Uranus, Neptune, and Pluto. He also discusses the search for Planet X.

The extrasolar planets recently found circling 51 Pegasi and 47 Ursae Majoris confirm that other planetary systems lie beyond our own. In his latest book Dr. Croswell explains the four basic astronomical ingrediants for life. Moreover, he demonstrates how new space-based and technologically advanced observatories could some day provide direct detailed images of our new planetary neighbors.

Club News Notes

We need help with nominations

Club President Dave Anderson requests your help with the nomination process for the upcoming election of board members and officers. He would like a few other TVS supporters to help him call club members from our phone list to ask them to consider joining our board.

This is also a good opportunity to get to know more TVS members and to learn about their experiences and interests. If several of you will volunteer, this job can be done fairly quickly and easily. (Dave called the entire membership list last year himself, but doesn't want to do it all himself this year.) Please contact Dave either by e-mail ( or phone (510 661-4249).

Our apologies to Ken Sperber

Ken Sperber submitted a well-researched article comparing films for prime focus photography. Un-fortunately, we could not process the article and its figures in time for this edition. Look for Ken 's hard work to appear next month.

Jump in Membership

Congratulations, you now belong to an amateur astronomy club boasting more than 200 members. Last month, 11 folks signed up with TVS.

Please extend your welcome to: Trina Alkema, Gert Gottschalk, Brett Hall, Dennis Morse, Bruce and Harriet Skelly, the John Stivers Family, Mike Walsworth, and Greg and Colleen Zamira.

Our apologies go to Victor Sickenger, whose name was misspelled when we welcomed him last month.

More on money

The board is in receipt of an e-mail from a concerned club member who strongly questioned the club's investment planning. As noted in the September Prime Focus, the board is evaluating potential investments at The Sky Shack and improvements for the club scope. For these reasons, long term investment vehicles do not seem appropriate.

While the Dark Sky Site committee assembles its recommendations for club expenditures, our short-term investments will change. Monies will be moved from the checking account and the money market fund into staggered-maturity, 90-day certificates of deposit. The club will then own a total of three CDs: the recently-renewed $3,201.37 certificate, and two new ones of $2,500 each.

This will leave approximately $2,4 50 in the club checking account. The balance of the club 's funds will remain split among the three CDs until the board presents its plans to the membership.

At that time, all proposed Sky Shack and scope expenditures will be noted in Prime Focus, and discussed at the following general meeting where a vote will be taken.

Planning meetings (the next is scheduled on Oct. 20, at Round Table Pizza in downtown Livermore, at 7:00 PM) are always open to all TVS members. If you have a concern about the use of club funds, or simply wish to be better informed about board decisions, please consider this your personal invitation to attend.

Sorry... Because this newsletter is being commercially printed, it is only six pages. Next month we will print all the articles that could not fit in October.

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
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: 203

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

Star parties

With the school year back in session, we expect to receive requests from teaches for star parties. Rich Green, school star party chair, has created an e-mail list of members to be notified with upcoming dates. If you wish to be added to his list, call him at (510) 449-2190 for his e-mail address.

Space permitting, school star party information will be printed here each month.

Your own star party!

Luckily, the evening of November 1-2 falls on a weekend. Assuming access to a large enough telescope, you and your friends will be able to observe six planets at sunset. Venus and Mars can be seen together in Sagittarius. In Capricornus, Jupiter, Uranus, and Neptune will decorate the sky. Solitary Saturn makes a wonderful sight amidst the stars in Pices.

For those willing to hang out a little longer, Orion adds even more excitement, with a rising time of approximately 11:00 PM

To make the evening particularly enjoyable, new moon occurs just the night before. Lunar illumination for November 1-2 should be just 3 %.

What's up in October

by Dave Anderson
October 1997
1 Wed New Moon 9:51 AM PDT.
Io occulted by Jupiter 11:33 PM
Europa transits 1:19 AM
2 Thu Rosh Ha-Shanah (Jewish New Year 5758, at sunset 6:43 PM).
Io transits Jupiter 8:49 to 11:07 PM; shadow transits 9:57 PM to 12:15 AM
3 Fri Europa occulted by Jupiter 8:01 PM, reappears from eclipse 1:17 AM
Io reappears from eclipse 9: 26 PM
4 Sat Excellent weekend for observing: No Moon after 8:46 PM
Fortieth anniversary of Sputnik 1 launch (USSR).
5 Sun Venus 7° south of Moon, and Mars nearby.
Europa's shadow transits Jupiter until 7:39 PM
Ganymede transits 7:05 to 10:42 PM; shadow transits 11:50 PM
7 Tue Callisto transits Jupiter 7:12 PM to 12:0 0 midnight.
9 Thu First Quarter Moon 5:22 AM
Saturn at opposition (mag 0.2; apparent diameter 19.7"; of rings 44.9").
Lunar Prospector launch scheduled. (One-year mapping mission from polar orbit around the Moon.)
Space Shuttle Columbia (STS-87) launch scheduled. (Microgravi ty experiments.)
Delta Cephei at maximum 3:04 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).
Io transits Jupiter 10:40 PM to 12:58 AM; shadow transits 11:53 PM
10 Fri Io occulted by Jupiter 7:51 PM, reappears from eclipse 11:22 PM
Europa occulted 10:30 PM
11 Sat Yom Kippur.
Mars 3° north of Antares.
Jupiter 4° south of Moon.
Io transits Jupiter until 7:26 PM; shadow transits until 8:39 PM
12 Sun Europa transits Jupiter until 7:49 PM; shadow transits 7:26 to 10:15 PM
Ganymede transits 10:50 PM
13 Mon Columbus Day.
Cassini-Huygens Mission to Saturn launch scheduled 2:40 AM
14 Tue Algol at minimum 10:41 PM Eclipsing binary drops from mag. 2.1 to 3.4 in about 5 hours. (Period is 2.867 315 days). Compare Alpha Persei (mag. 1.79), Gamma Andromedae (2.2 6) and Delta Persei (3.01).
15 Wed Full Moon ("Hunter's Moon") 8:46 PM
Saturn 0.4° south of Moon (occulted in Asia).
16 Thu Asteroid 4 Vesta (mag 6.4) at opposition.
Venus 1.7° north of Antares.
Ganymede reappears from eclipse by Jupiter 9:23 PM
Callisto reappears 9:27 PM
Io transits 12:33 AM
17 Fri Tri-Valley Stargazers meeting 7:30 PM Unitarian Universalist Church in Livermore, 1893 N. Vasco Road, Livermore. (3/4 mile north of I-580).
Algol at minimum 7:29 PM
Io occulted by Jupiter 9:43 PM
18 Sat Io transits Jupiter 7:01 to 9:18 PM; shadow transits 8:18 to 10:35 PM
19 Sun Delta Cephei at maximum 8:39 PM
Europa transits Jupiter 7:29 to 10:19 PM; shadow transits 10:01 PM
Io reappears from eclipse 7:46 PM
Aldebaran occulted by Moon 12:48 to 1:56 AM
Venus centered between Mars and Antares.
20 Mon TVS Planning Meeting 7:00 PM Round Table Pizza, 1540 First St., Livermore (in Orchard Supply/Longs/Safeway shopping center).
21 Oct Yerkes Observatory's 100 th birthday.
Europa reappears from eclipse by Jupiter 7:53 PM
22 Wed Last Quarter Moon 9:48 PM
23 Thu Ganymede occulted by Jupiter 8:05 PM, reappears from eclipse 9:44 PM
24 Fri Io occulted by Jupiter 11:36 PM
25 Sat Io transits Jupiter 8:55 to 11:12 PM; shadow transits 10:14 PM
26 Sun Daylight Saving Time ends (2:00 AM PDT becomes 1:00 AM PST).
Venus 2° south of Mars.
Io reappears from eclipse by Jupiter 8:41 PM
Europa transits 9:01 PM PST.
28 Tue Europa reappears from eclipse by Jupiter 9:31 PM
30 Wed Ganymede occulted by Jupiter 7:23 to 11:01 PM
31 Fri Halloween.
New Moon 2:01 AM
Excellent weekend for observing.

November 1997
1 Sat Callisto occulted by Jupiter 9:21 PM
Io transits 9:50 PM PST.
Algol at minimum 2:33 AM Eclipsing binary drops from mag. 2.1 to 3.4 in about 5 hours. (Period is 2.8673 15 days). Compare Alpha Persei (mag. 1.79), Gamma Andromedae (2.2 6) and Delta Persei (3.01).
2 Sun Io occulted by Jupiter 6:59 PM, reappears from eclipse 10:36 PM
3 Mon Mars 6° and Venus 9° south of Moon.
Ganymede's shadow transits Jupiter until 6:35 PM
Io transits until 6:36; shadow transits until 7: 55 PM
Ganymede's shadow eclipses Io (partial; 96% light drop) 10:2 3 to 10:55 PM
Algol at minimum 11:22 PM
4 Tue Election Day.
Europa occulted by Jupiter 6:32 PM
Delta Cephei at maximum 10:02 PM Variable rises to mag. 3.5 from 4.4 in about 1.5 days. (Period is 5.3663 41 days). Compare Zeta Cephei (mag. 3.35 ) and Epsilon Cephei (mag. 4.2).
5 Wed Venus at greatest eastern elongation (47° ), but also at extreme southern declination (-27° 01'), making this a poor evening apparition for northern latitudes.
6 Thu Algol at minimum 8:11 PM
Galileo flyby of Europa (1,119 km).
Europa's shadow transits Jupiter until 6:21 PM
7 Fri First Quarter Moon 1:43 PM
9 Sun Io occulted by Jupiter 8:54 PM

Some Fall Deep-Sky Objects

M57 The Ring Nebula, a famous planetary nebula in Lyra.
M27 The Dumbbell Nebula, a superb planetary in Vulpecula!
NGC6960/ 92/9 5 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.
M15 Rich, compact globular cluster in Pegasus.
NGC7009 The Saturn Nebula, a bright planetary nebula in Aquarius.
NGC7293 The Helix Nebula, a large planetary nebula, also in Aquarius.
NGC7331 A large, bright spiral galaxy in Pegasus. Stephan's Quintet is nearby.
M31, M32, M110 The Andromeda Galaxy (and companions)! Marvelous with any instrument, even unaided eye.
NGC7662 Blue Snowball planetary nebula in Andromeda, a bright annulus.

Comet Comments

by Don Machholtz


C/1995 O1 (Hale-Bopp)
Date (00UT) R.A. (2000) Dec El Sky Mag
10-04 08h08.9m -38° 46' 70° M 6.1
10-09 08h10.0m -40° 53' 72° M 6.2
10-14 08h10.5m -43° 00' 75° M 6.3
10-19 08h10.3m -45° 05' 77° M 6.4
10-24 08h09.3m -47° 08' 79° M 6.5
10-29 08h07.6m -49° 09' 81° M 6.6
11-03 08h04.9m -51° 07' 83° M 6.7

C/1997 J2 (Meunier-Dupouy)
Date (00UT) R.A. (2000) Dec El Sky Mag
10-04 15h05.1m +60° 15' 71° E 11.1
10-09 15h23.8m +59° 24' 72° E 11.1
10-14 15h39.5m +58° 30' 73° E 11.0
10-19 15h55.2m +57° 33' 73° E 11.0
10-24 16h10.9m +56° 33' 74° E 10.9
10-29 16h26.5m +55° 30' 74° E 10.9
11-03 16h42.0m +54° 25' 75° E 10.8

A faint comet has been discovered "automatically" by the Spacewatch equipment at Kitt Peak. Comet C/1997 P2 (Spacewatch) will remain faint. Six more short-lived faint comets have been found on images obtained by the solar-orbiting SOHO satellite; its total is now 26. Meanwhile, Comet Hale-Bopp is now in the morning southern sky and Comet Meunier-Dupouy slowly brightens in our evening northern sky.

COMET HUNTING NOTES: With so many comets from the Kreutz Sungrazing Group being discovered by the SOHO satellite, amateurs have taken a renewed interest in sweeping along the path by which these comets are arriving. That path is now in the morning sky, having been behind the sun this past summer. The comets are very faint in the weeks before perihelion and it may take CCD imaging to capture them. The brightest members, although rare, can still be discovered visually.

Orbital Elements

Object: Hale-Bopp Meunier-Dupouy
Peri. Date: 1997 04 01.13800 1998 03 10.4346
Peri. Dist (AU): 0.9141405 AU 3.050393 AU
Arg/Peri (2000): 130.58915 deg. 122.6927 deg.
Asc. Node (2000): 282.47069 deg. 148.8384 deg.
Incl (2000): 089.42943 deg. 091.2715 deg.
Eccen: 0.9951172 1.001491
Orbital Period: ~2500 years Long Period
Ref: MPC 29568 MPC 30429

Tri-Valley Stargazers Membership/Renewal Application
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