Prime Focus

Newletter of the Tri-Valley Stargazers for April 1998
This unnamed asteroid left a bright trail while passing a galaxy in Leo. With a visual magnitud e of only 21.8., and a diameter of half a mile (0.8 km), the rocky body was located by the Hubble Space Telescope at about 188 million miles from Earth, and 233 million miles from the Sun. (R. Evans and K. Stapelfeldt (Jet Propulsion Laboratory) and NASA.)


April general meeting
The TVS Telescope Making Workshop
Club news notes
What's Up
Comet Comments
Project ASTRO
Chabot Observatory
30th annual RTMC
Sky Shack poll/ballot

TVS presents

What: Public Service Astronomy
Where: Unitarian Universalist Church in Livermore, 1893 N. Vasco Rd.
When: April 10, 1998
Conversation, 7:00 PM Program begins, 7:30 PM
Who: You and your family
John Dobson

Believe it or not, the internationally renowned Dobsonian telescope mount originated from a collection of salvaged parts and pieces at the Vedanta Monastery in Sacram ento. It was there that John Dobson, living a monastic life, began grinding his own mirrors and building his own scopes.

In 1967, after 23 years as a monk, John emerged to dedicate the remainder of his life to public service astronomy. Since then, he founded the Sidewalk Astronomers and has taught telescope-making and astronomy at the Randall Museum, the Jewish Community Center, and the California Academy of Sciences. John still teaches at CAS.

The Dobsonian mount, which John declined to patent, has made large user-friendly telescopes accessible and affordable for the general public. Thousands of amateur astronomers, many TVS ATMs included, have made their own sturdy, low-cost Dobsonian telescopes. Please join TVS for an extraordinary evening with John Dobson on April 10. Newcomers and guests are particularly invited to this very special meeting.

ATMs at it again

by Rich Combs

Amateur telescope making is alive and well! Many club members and friends have expressed interest in making their own telescopes, including making their own mirr ors. In response, for the sixth year running, the club will sponsor an Ama teur Telescope Making workshop. Club members with experience in mirror grinding and telescope fabrication will show you the tricks of the trade. You'll grind, polish, and figure a 6" f/8 mirror. Then you'll build a Dobsonian mount, add a secondary mirror, focuser, and finder, to create a complete telescope.

So come join us! No special skills or equipment are necessary, only perseverance. It will require a time commitment of about 30-40 hours, and will cost $300-400. The following estimated costs and class details explain a little more about the workshop.

Mirror and Accessories Costs
This workshop is aimed at the first-time mirror maker, and the breakdown that follows is for a "first" scope. Experience from the previous workshops has convinced me that your first scope should be a 6" f/8. However a number of folks have expressed interest in making a second scope, or buying a large mirror and building the mount, and we will be happy to estimate the details of each individual project with you.

Estimated costs
Workshop fee $ 50
6" mirror blank, Pyrex $26
6" tool, plate glass $15
Abrasives, pitch $15
Focuser $70
Secondary mirror $41
Secondary holder $30
Misc. hardware $40
Reflex finder $40
Eyepieces $35-70
If you buy everything, the project will cost about $400. If you already have some of the parts required, the cost will be correspondingly lower. You choose your own package to fit your desires and pocketbook. We will help you build whatever you choose.

Meeting Arrangements
The Nunes Family, TVS members, have offered the use of a building on their property in Sunol as a grinding shop. We will meet Monday and Wednesday evenings from 7 to 9, and a few Saturday mornings from 8:30 to 12:30. Although the first meeting was held March 16th, we still welcome new ATMs as TVS "grit pushers". Feel free to contact me if you have questions.

Rich Combs (510 ) 846-1906, home (510) 423-8987 work e-mail: (home)

Club News Notes

More about money
The board continues to work on the improvement plans for our leased dark sky site. No investments have yet been made, and the club will be informed of all board recommendat ions before funds are spent. For the interim, our capital remains in the checking account and three certificates of deposit. Approximately two-thirds of the 1997 membership had paid renewal dues as of March 20.

On that date, our current financial status was:
Checking account: $3,906.25
CD #1 3,276.27
CD #2 2,519.67
CD #3 2,023.53.

Our largest annual operating expenses, excepting newsletter mailing, are the leases at the church and the observing site. They have both been paid for this year. Magazine subscriptions collected from members have been forwarded to the respective publi shers. TVS particularly thanks members Dave Scimeca and Denis Morse for their contributions made this year. Thanks for keeping the club in mind!

One unusual expense was approved at the March planning meeting. Mike Rushford provided the club mirror site for a Webcast of the February eclipse. At the February general meeting he had requested club help with the international phone connections that would enable live transmission. Although Mike ultimately received donations to cover those costs, he did incur unexpected charges for the high number of hits the site enjoyed. The board approved a reimbursement, not to exceed $200, in the event Mike does not receive donations to cover his Web expenses on behalf of TVS.

Star Parties

Back to the park

Public star party chair Jim McIntire seeks help from members interested in the Sycamore Grove star parties in Livermore. Jim met with the Livermore Area Parks and Recreation District to set four dates for future parties: June 20, July 18, August 15, and September 19. He needs members who are willing to give a basic astronomy talk, before the public moves on to viewing with the scopes.

Interested members can choose a favorite astronomy topic for the party at which they wish to speak. The LARPD newsletter will even feature the TVS member and his or her topic. For all the details, contact Jim at (209) 836-3836, or e-mail him at

School Star parties Phil Waide, our school star party coordinator, has received two requests for April star parties. You may contact Phil at (510) 455-6039.
April 2, Arroyo Mocho School in Livermore
April 7, Granada High School in Livermore

Future parties have been requested by: Susan Schatz, Kennedy Elementary School in Newark, and Ron Wurtz, Jackson Avenue School in Livermore.

Public star parties are coordinated by Jim McIntire, who announces the following events:
June 20, Sycamore Grove Park in Livermore
June 26-28, Camp Shelly at Lake Tahoe July 18, Sycamore Grove Park in Livermore
August 15, Sycamore Grove Park in Livermore
August 21-23
, Camp Shelly at Lake Tahoe
September 4-6, Glacier Point at Yosemite

To reach Jim call 209 /836-3836.

The White Mountains club star party is set for Thursday, July 23 through Sunday, July 26. Dave Rodrigues will announce deadlines and costs at a future meeting.

Project ASTRO note

Sierra Nevada Field Campus, a program of San Francisco State University, is offering an Astronomy 216 course this summer (July 19-24) "Practical Observational Astronomy from the Sierra Nevada." The course fee is $165. Sierra Nevada Field Campus is located just east of Sierra City near the base of the spectacular Sierra Buttes. For more information check out or contact: Nicole S. Taddune Bay Area Project ASTRO Coordinator Astronomical Society of the Pacific 390 Ashton Avenue San Francisco, CA 94112 (415) 337-1100 ext. 101 //

Brave new members

Despite the worst February observing weather in anyone's memory, intrepid astronomers continued to join us last month. Please help welcome the Larry and Elena Hood family, the Brent and Veronica Scott family, and Ron Frank. Our membership total, with each family counted as two, now stands at 151. Late renewals, of course, are still welcome.

Observatory happenings

Observatory director Chuck Grant is researching the question of an equitorial-vs-fork mount for the Sky Shack 17.5" telescope. Chuck would appreciate hearing from members with experience in welding and machining. He is also trying to discover local facilities where club members could perform such work on a new mount, as our time and budget allow. If you possess either of these skills, or have access to welding or machining equipment, please call Chuck at 510 449-1500.

Two members have addressed detailed letters to the board. They are filled with suggestions for Sky Shack uses, upgrades and improvements. We welcome all input, and members are always invited to the monthly planning meetings. (Dates are listed in "What's Up") The observatory and dark sky site are important agenda items for the April planning meeting, so please send your suggestions or come in person.

Calling 9-2-5
You may be aware that the Tri-Valley telephone area code is changing. During this period of "permissive dialing" (Pac Bell's turn of phrase, not ours!), your callers may use 510 or 925. Come mid-September, the 925 code will replace 510 permanently. We will notify you of TVS changes.

Open what...?
The soon-to-be-renamed Sky Shack will be open for club members and their escorted guests on selected dates over the spring and summer. The board balances Patron member benefits with other club commitments in choosing these dates, and for that reason, only the first two have been set so far.

Mark your calendars for the Saturdays May 16 and July 18 if you want to be part of the fun. Meet where Tesla Road turns the corner onto Mines Road about 10 minutes before 6 o'clock on the evening of the open house. We will caravan from that spot at 6 PM, leading TVS cars through the gates and parking so that those who do not overnight can leave without backing up. Entry to the site costs $3 per car, and exact change is required. A club officer will show you how and where to pay when you arrive.

Circle these dates
Remaining 1998 general meetings are set for the second Friday of each month as follows:

April 10 May 8 June 12
July 10 August 14 Sept. 11
Oct. 9 Nov. 13 Dec. 11

Newsletter deadline notice
Due to the editor's travel schedule, Prime Focus deadlines are slightly changed for the May and June editions. Material for the May edition must be received by April 10, 5:00 PM For the June newsletter, submissions are due not later than May 9, 5:00 PM You may send e-mail or faxes per the information in the box on page two. Typed copy must be delivered to: Circle Wing, 184 Airway Blvd., Livermore, CA 94550. Thanks for your cooperation. We should be back to normal (the 15th) for the July edition.

SAA Web page

The Stockton Astronomical Society is pleased to announce that it now has a web page. Point your browser to Stockton Astronomical Society

President Dave Anderson 510 661-4249
Vice President
Chuck Grant (925) 449-1500
Secretary Bill Burnap (510) 449-4552
Treasurer Gene Nassar (510) 462-7843

Alane Alchorn, Dennis Beckley, Rich Combs, Rich Green, Kathleen Kelly, Russ Kirk, Dave Rodrigues, Debbie Scherrer, Jim Zumstein

Observatory Director Chuck Grant 925 449-1500
Editor Alane Alchorn 510 455-9464 fax: 510 455-9466
Librarian Chris Cody (707) 747-6550
Eyes on the Skies Mike Rushford
Website Chuck Grant
Meeting Location Unitarian Universalist Church in Livermore 1893 N. Vasco Rd. 3/4 mile north of I-580

Tri-Valley Stargazers

P.O. Box 2467
Livermore, CA 94551

Membership: 151

Comet Comments

by Don Machholtz


C/1997 J2 (Meunier-Dupouy)
Date (00 UT) R.A. (2000)DecElSkyMag
04-02 21h53.6m +31° 35 48° M 11.7
04-07 21h58.8m +31° 27' 50° M 11.7
04-12 22h03.6m +31° 20' 51° M 11.6
04-17 22h08.2m +31° 13' 53° M 11.6
04-22 22h12.3m +31° 07' 55° M 11.6
04-27 22h16.1m +31° 01' 58° M 11.6
05-02 22h19.5m +30° 55' 60° M 11.6
05-07 22h22.5m +30° 49' 63° M 11.6

C/1995 O1 (Hale-Bopp)
Date (00 UT) R.A. (2000)DecElSkyMag
04-02 05h02.4m -53° 06' 79° E 9.3
04-07 05h05.3m -52° 32' 78° E 9.4
04-12 05h08.5m -52° 01' 78° E 9.5
04-17 05h11.9m -51° 33' 77° E 9.5
04-22 05h15.7m -51° 07' 76° E 9.6
04-27 05h19.6m -50° 45' 76° E 9.7
05-02 05h23.8m -50° 26' 75° E 9.7
05-07 05h28.1m -50° 10' 75° E 9.8

Comet Hale-Bopp slowly dims deep in the southern sky. It is still displaying a short tail. Meanwhile, Comet Meunier-Dupouy continues its travels in the morning sky. Both comets are about three astronomical units away.

COMET HUNTING NOTES: Of the 100 comets visually discovered since 1975, only one was found without the use of a reflector, refractor or binoculars. It was Merlin Kohler's comet discovery on Sept. 3, 1977. He used an 8" Dynascope Schmidt Cassegrain. This discovery took about forty hours of sweeping. Mr. Kohler is now retired and still living in Quincy, California. Orbital Elements
Object: Hale-Bopp Meunier-Dupouy
Peri. Date : 1997 04 01.13 47 1998 03 10.43 65
Peri. Dist (AU): 0.914008 AU 3.051015 AU
Arg/Peri (2000): 130.5787 deg. 122.6755 deg.
Asc. Node (2000): 282.4653 deg. 148.8429 deg.
Incl (2000): 089.4268 deg. 091.2731 deg.
Eccen: 0.99 5085 1.00 0760
Orbital Period: ~250 0 years Long Period
Ref: MPC 30738 MPC 30738
Epoch: 1997 12 18 1998 03 08
Absol. Mag/"n": -1.0/4.0 4.0/ 4.0

Chabot Observatory and Science Center events

Jose Olivarez, director of astronomy announces programs that include viewing the night sky through the magnificent Chabot telescopes, weather permitting. Chabot Observatory is located at 4918 Mountain Blvd., Oakland. Tickets are available in the Starry Nights Gift Shop on site. To make reservations or for more information call 510 530-3480. (Prices: adults: $5.00, seniors $4.50 and youths, 6-17, $3.50.)

Worlds Unnumbered - The Search for Extrasolar Planets
Special guest lecture and book signing by astronomer and author Donald Goldsmith, Ph.D. April 24 7:30 PM For centuries, humans have speculated about the planets that may orbit distant stars. Through four decades of space exploration and ever-better telescopes, astronomers had searched in vain, unable to find even a single planet orbiting any sunlike stars. All of this changed in October 1995, when astronomers announce d the first planet discovered orbiting another sunlike star. Since then, many other planets have been discovered, providing firm evidence that planetary systems exist in abundance. Dr. Goldsmith 's lecture discusses the charact eristics and significance of these new worlds.

The Search for Extraterrestrial Life
May 1 through June 13 7:30 PM The search for the "stuff of life" among the planets of our solar system continues, and so does the quest for an intelligent message from the stars. In our solar system, Jupiter 's moon Europa may harbor an ocean of

water, and Saturn 's Titan may mimic the chemistry of an early Earth. In this show, participants will explore these moons and learn how radio astronomers are listening for messages from the stars.

SETI: Science Fact, Not Fiction
Special guest lecture by Astronomer Jill Tarter, Ph.D. June 19 7:30 PM Aliens abound on movie screens, but in reality we are still trying to discover whether we share our universe with other sentient creatures. Intelligence is very difficult to define, and impossible to directly detect over interstellar distances. Therefore, SETI, the search for extraterrestrial intelligence, attempts to detect evidence of another distant technology.

Liquid Nitrogen Show
June 26 and 27 7:30 PM At -320 F, liquid nitrogen is one of the coldest things you 'll ever experience. See what happens to common objects when they come in contact with liquid nitrogen. We will also explore hydrogen, the most abundant element in the universe. Learn where these elements were produced and witness a mini "Big Bang"!

SkyWatch Tours
Tuesdays and Thursdays, 8 PM, beginning June 16, by group reservation. See the constellations in the planetarium and learn about celestial objects visible in the summer sky.

Riverside Telescope Makers Conference (RTMC)

The 30th annual RTMC is set for Memorial Day weekend, May 22-25, at Camp Oakes, Big Bear California. Located 50 miles northeast of Riverside, in the San Bernardino Mountains, this site offers space for camping, several dormatories, 18 three-sided shelters, a meeting and dining hall, and the Charles Walker Observatory. The camp sits at an elevation of about 7,600 feet.

Rocks in Space
Eleanor Helin, Ph.D. is the keynote speaker for this year 's theme, "Rocks in Space". Dr. Helin 's talk is titled "Detecting Asteroids and Commets with a NEAT System." Her presentation is scheduled for Saturday, May 23, at 4:00 PM in the meeting hall.

Beginner 's Corner
The popular Beginner 's Corner will continue as an RTMC feature. This is an excellent opportunity for the novice astronomer to learn about the hobby through talks, demonstrations and workshops. The session was particularly created to stimulate interest in amateur astronomy and telescope making.

Nearly new moon
day Moonrise Moon set
Friday, May 22 3:39 AM 4:27 PM
Saturday, May 23 4:20 AM 5:36 PM
Sunday, May 24 5:03 AM 6:45 PM

For RTMC details, point your browser to

Sky Shack opinion poll and observatory name ballot

Please complete the opinion poll and ballot below. If you have not already renewed your 1998 membership, please complete that as well. Family members should photocopy this form as needed. Send your response to the post office address on page two. Results will be published in the May Prime Focus. The board will select the final name from the top five finishers in this balloting. Protecting the privacy of our leased site is the top priority for TVS.

Sky Shack name change ballot
____ Pine Shack Obs.
____ Hidden Hills Obs.
____ Red Mountain Obs.
____ Cedar Ridge Obs.
____ The Dark Site
____ Lick Obs. East
____ Eastern Mt. Hamilton Obs.
____ San Antone Valley Obs.
____ Mines Road Obs.
____ Jack's Obs.
____ Sweetwater Obs.
____ Keck III
____ Middle of the Ranch Obs.
____ Celestial Temple Obs.
____ Other ________ ____________ ____________ _________

Dark sky site opinion poll Rank your preferred uses for the club's observatory and dark sky site, with #1 as your highest choice. Please attach a separate sheet if you would like to send detailed comments.

____ Astrophotography, using the club scope
____ Astrophotography, using your own instruments
____ Deep sky observing
____ Solar system/planetary observing
____ Comet hunting
____ Open house/star party events
____ Research/profess ional quality observations
____ Visual astronomy, using the club scope
____ Visual astronomy, using your own instrument
____ Unaided eye/binocular observing
____ Social observing events with other amateurs
____ Other, as noted below

________ ____________ ____________ ____________ _______ ________ ____________ ____________ ____________ _______

Tri-Valley Stargazers Membership/Renewal Application
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