Prime Focus

The newsletter of the Tri-Valley Stargazers September 1996.
Translated (roughly) from postscript into HTML for your browsing and downloading pleasure.
Thank you, Chuck Vaughn, for this spectacular shot of Comet Hale-Bopp. Chuck captured this image on August 15 (0445UTC) from The Dark Site, using his 12.5"-f/9 Ritchey-Chretien. The exposure time was 90 minutes on Tech Pan 2415.


September general meeting
Oh, what a night!
Club news notes
What's Up in September
Comet Comments
Early fall deep-sky objects
Membership application

TVS presents

What: September general meeting
When: September 27 at 7:30 PM
Who: Jack Marling, Lumicon
Where: Unitarian Universalist Church in
Livermore, 1893 N. Vasco Rd.

Once again TVS is pleased to present member Jack Marling as a featured speaker. Jack will discuss observing tips and techniques at the September general meeting, scheduled for the evening after the eclipse.

Jack is internationally known for his research and development of outstanding deep-sky filters and his newly patented multiple-filter selector holding up to five 1.25 inch filters on a sliding bar. This is the meeting to attend for help with hypersensitized film, coma correctors, computer guiding and improving your overall observational skills. All club members are also invited to share favorite tools and techniques. If you have a gadget, book or tool that you think might help other members, please bring it to the meeting and let us know, too.

Oh, what a night!

Don't bother to set your alarm for Friday morning on September 27. You will have been up for the entire night before. Like all of the western hemisphere, you can enjoy the lunar eclipse. You can then cap your evening by observing Saturn moving through opposition.

September 26 is one of those nights that amateur astronomers are sure to swap lies about. Saturn will pass just three degrees south of the Moon at about 9:00 pm our time. For us, the Moon will rise in partial eclipse, with total eclipse beginning at 7:19 pm. Total eclipse ends at 8:29 pm and the Moon leaves penumbra at 10:36 PM.

Binoculars will be particularly useful for those who want to watch Earth's shadow as it recedes across lunar features like craters, rilles and the Straight Wall.

It will be particularly interesting to observe Saturn and the Moon, as they move away from each other over the course of the night. The precise conjunction visible at 9:00 pm will shift slightly as the Moon appears to move eastward.

Club News Notes

Lunar eclipse school star party

President Dave Anderson is working with teachers Ed Roberts and Melanie Yee, at Hopkins Junior High in Fremont, on Project ASTRO. He would like members to join him for a lunar eclipse star party, Thursday September 26. Call him at 510/661-4249 or 510/770-4900 to volunteer, and for directions.

The Dark Site combination revisited

As you probably noticed in last month's Prime Focus, the Mines Road gate combination has been changed at the entrance to The Dark Site Ranch. Members who hold a Sky Shack Observatory key are entitled to know the new combination, but very few of you have called asking for it!

At the August board meeting, the directors became concerned that the existance of a new combination was not widely known. So, all of the information is being reprinted here this month. Please contact any club officer listed below in order to receive the new combination. Have your observing hill key in hand so that your number can be verified. Thank you for helping to preserve TVS access to The Dark Site.

If you hold a key, please remember that you have already agreed to honor the following points in your User Agreement for The Dark Site.

1) Pay $3 per car, per visit, and place this money into the slotted box mounted on the post to the south of the owner's home.

2) Always leave the observing hill gate closed and locked Leave the Mines Road gate, and any other ranch gates, in the same condition as you found them.

3) Accompany any guest you bring at all times .

4) Alcoholic beverages are forbidden on the observing hill and ranch.

5) All fires are prohibited all year long. This includes barbecues and camp stoves.

6) Keys may not be duplicated, transferred or shared. Please drive slowly, about 5 miles per hour, to prevent dust clouds from forming behind your car. It is important for us to remember that using The Dark Site is a privilege - one that all of us need to protect.

Welcome, new members

Summer stargazing inspired at least 12 amateur astronomers to join TVS last month. Counting each family membership as just two persons brings our latest membership estimate to 175. At the next general meeting or the October open house at The Dark Site please extend a warm welcome to: Ted Judd, the Jeff Friedman family, Doug Gallacher, Ed Snyder, the Jeff and Sue Smith family, Goeff Gilbert, Allan Stern, Linda Labonte, and Lawrence and Alfreda Zuckerman.

Al Stern is familiar to many of us through his work at Project ASTRO and AANC. Thanks for joining TVS, Al.

Money matters

Checking account: $4,960.44 Certificate of deposit: $3,054.98 Money market fund: $1,191.96

The certificate of deposit holds all key deposits posted for the The Dark Site Sky Shack, and earned interest is retained in the account. A deposit is fully refunded upon surrender of a member's key. The money market fund is the club savings account.

TVS rents additional space at the church

Beginning with the September 27 general meeting, the club will rent storage space in the church's religious education building adjacent to the sanctuary build ing where meetings are held.

This storage area is seperately keyed from the rest of the religious education building. Club property will be accessed only by club officers or someone else they appoint. The club library, including back issues not typically available at general meetings, will be kept in the storage area. Additionally, unrented loaner scopes can be warehoused there.

The sound system, overhead projector, projector screen, and hospitality supplies will also be kept in this room. The church is renting this space without liability for club contents stored there. TVS will pay $300 additional per year (pro-rated to February \22197) for access to this room.

Club Calendar

General meeting dates: September 27 October 25
November 22 December 20

Open house at The Dark Site Sky Shack: October 5 (Saturday) To caravan to the The Dark Site gate, meet the group at 5:30 pm at the Tesla/Mines Road intersection.

Star parties: September 21 Sycamore Grove, Livermore
Planets and the solar system September 26 Fremont location pending
Lunar eclipse public party, contact President Dave Anderson 510 /661-4249 to volunteer. October 19 Sycamore Grove, Livermore
Astronomy day and ATM graduation/reunion

President Dave Anderson (510) 661-4249
Secretary Earl Mack (510) 828-1414
Vice President Bob Braddy (510) 855-0964
Treasurer Gene Nassar (510) 462-7843
Observatory Director Chuck Grant (510) 449-1500
Eyes on the Skies BBS Mike Rushford (510) 443-6146
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

Alane Alchorn
Dennis Beckley
George Cameron
Rich Combs
Chuck Grant
Rich Green
Al Smith

Tri-Valley Stargazers

P.O. Box 2467
Livermore, CA 94551
Membership: 175

What's Up for September 1996, by Dave Anderson

20 Fri First quarter Moon 4:23 AM
Jupiter 6° south of Moon (and 1° from globular cluster M22 throughout month)
Io transits Jupiter 9:08 to 11:22 PM; shadow transit begins 10:25 PM
Ganymede transit begins 10 :41 PM
21 Sat Star party at Sycamore Grove Park (Livermore Park District) 8:00 PM (Wetmore Rd. entrance near Holmes St.)
Io reappears from eclipse by Jupiter 9:49 PM
22 Sun Autumnal equinox 11:00 AM
Neptune 5°, then Uranus 6° south of Moon
23 Mon Europa transits Jupiter 8:19 to 11:05 PM; shadow transit begins 10:53 PM
Yom Kippur
24 Tue Ganymede reappears from eclipse by Jupiter 9:04 PM
25 Wed Callisto occulted by Jupiter 8:15 PM
Europa reappears from eclipse 8:52 PM
26 Thu Full Moon ("Harvest Moon") 7:51 PM
Total lunar eclipse. Moonrise 6:51 PM (partial phase underway); total phase 7:19.2 to 8:29.3 PM; partial phase ends 9:36.4; penumbral phase ends 10:3 6.5 PM
Saturn at opposition (mag. 0.5), 3° south of Moon.
27 Fri Tri-Valley Stargazers meeting 7:30 PM PDT. Unitarian Universalist Church in Livermore, 1893 N. Vasco Road, Livermore. (3/4 mile north of I-580).
28 Sat Io occulted by Jupiter 8:09 PM
30 Mon TVS planning meeting 7:00 PM Rich Green's, 4741 Appletree Common, Livermore. (Call 449-2190 for information or directions.)
1 Tue Aldebaran 0.8° south of Moon; occulted in Europe.
3 Thu Mercury at greatest western elongation (18 ° ). Most favorable morning apparition of year for northern latitudes.
Venus 0.5° south of Regulus. (Rise about 3:30 AM PDT)
4 Fri Last quarter Moon 5:04 AM Good weekend for observing.
Asteroid (3) Juno at opposition (mag. 7.5). See October Sky & Telescope, p. 69.
5 Sat Open house at The Dark Site. Meet at the corner of Mines and Tesla Roads, Livermore, at 5:30 PM
6 Sun Io transits Jupiter 7:27 to 9:41 PM; shadow transit begins 8:44 PM
7 Mon Io reappears from eclipse by Jupiter 8:08 PM
Mars 6° north of Moon. (Rise after 2 AM)
8 Tue Ganymede occulted by Jupiter 8:34 PM
Venus 4° north of Moon.
9 Wed Europa occulted by Jupiter 8:38 PM
10 Thu Algol at minimum 1:28 AM
12 Sat New moon 7:14 AM
Partial solar eclipse visible in Europe and northern Maine. Excellent weekend for observing.
Algol at minimum 10:17 PM
14 Mon Columbus Day.
18 Fri Groundbreaking for new Chabot Observatory and Science Center, 10:00 AM
Jupiter 6° south of Moon.
Io shadow transit of Jupiter begins 8:01 PM Satellite transit ends 8:19 PM
19 Sat Astronomy Day II.
Star party at Sycamore Grove Park (Livermore Park District) 8:00 PM (Wetmore Rd. entrance near Holmes St.).
Mars in M44 (Praesepe). Look before dawn.
First quarter Moon 11:09 AM
Neptune 5°, then Uranus 6° south of Moon.
Ganymede's shadow transits Jupiter beginning 7:54 PM

Comet Comments

By Don Macholz Comet


C/1995 O1 (Hale-Bopp)
DATE(00UT) R.A. (2000) DEC El. Sky Mag
09-19 17h30.9m -05° 33' 86° E 5.1
09-24 17h30.0m -05° 19' 81° E 5.1
09-29 17h29.7m -05° 04' 77° E 5.0
10-04 17h29.9m -04° 50' 72° E 4.9
10-09 17h30.6m -04° 35' 68° E 4.8

22P/ Kopff
DATE(00UT) R.A. (2000) DEC El. Sky Mag
09-19 20h15.0m -23° 52' 124 ° E 9.4
09-24 20h22.7m -23° 35' 121 ° E 9.6
09-29 20h30.6m -23° 15' 118 ° E 9.9
10-04 20h38.9m -22° 51' 115 ° E 10.2
10-09 20h47.3m -22° 23' 112 ° E 10.4

C/1996 N1 (Brewington)
DATE(00UT) R.A. (2000) DEC El. Sky Mag
09-19 16h16.6m +56° 30' 77° E 10.7
09-24 16h48.9m +57° 33' 80° E 10.9
09-29 17h23.7m +58° 06' 84° E 11.1
10-04 17h59.9m +58° 04' 88° E 11.3
10-09 18h36.3m +57° 27' 92° E 11.5

C/1996 E1 (NEAT)
DATE(00UT) R.A. (2000) DEC El. Sky Mag
09-19 18h14.5m +70° 51' 91° E 10.3
09-24 18h44.8m +63° 36' 95° E 10.3
09-29 19h04.7m +55° 57' 98° E 10.5
10-04 19h19.2m +48° 17' 100° E 10.6
10-09 19h40.6m +34° 12' 99° E 11.0

NEAT, discovered March 16 by a CCD camera attached to a 39-inch telescope atop Mt. Haleakala in Hawaii, has brightened to a magnitude that is observable in amateur's scopes. NEAT stands for Near-Earth Asteroid Tracking; it was designed to detect earth (orbit) crossing asteroids and comets. The equipment for this project, funded by both JPL and the U.S. Air Force, consists of a CCD camera and electronic scanning software. It is one of several new comet and asteroid discovery systems currently being developed.

Mean while, Comet Brewington remains in our evening western sky while Periodic Comet Kopff fades in our evening southern sky. Comet Hale-Bopp, still some 250 million miles away from us, is visible to many astronomers without optical aid. A telescope shows a coma that is about a quarter-degree in size and a tail nearly a half-degree long. The comet is slowly moving northward; it remains within eight degrees of the equator until early 1997.

Orbital Elements
Object Hale-Bopp Kopff Brewington NEAT
Peri. Date 1997 03 31.86770 1996 07 02.19980 1996 08 03.42997 1996 07 27.36189
Peri. Dist (AU) 0.9170703 AU 1.5795617 AU 0.9257232 AU 1.3585919 AU
Arg/Peri (2000): 130.40061 deg. 162.83487 deg. 043.97835 deg. 81.12936 deg.
Asc. Node (2000): 282.46983 deg. 120.91329 deg. 234.91014 deg. 149.84329
Incl (2000) 089.38442 deg. 004.72143 deg. 052.13812 deg. 114.47220
Eccen: 0.99674010 0.5440739 1.0 1.0005638
Orbital Period: 4700 yrs. 6.45 yrs. Long period Long period
Ref: MPC 26879 (3-26) MPC 22032 (1991) MPC 27542 MPC 27428

Some early fall deep-sky objects

M57 The Ring Nebula, a famous planetary nebula in Lyra.
M27 The Dumbbell Nebula, a superb planetary in Vulpecula!
NGC6960/92/95 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.
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.
NGC7789 Very rich but faint open cluster in Cassiopeia.
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.
NGC891 Faint but striking edge-on spiral galaxy in Andromeda.

TVS Membership Application
Since November 1, 1996 we estimate that this page has been downloaded about times.

Thanks for visiting.