Prime Focus

The newsletter of the Tri-Valley Stargazers April 1996.
Translated (roughly) from postscript into HTML for your browsing and downloading pleasure.

Cran Lucas shot Comet Hyakutake (96B2) on approach March 19. He used Fujichrome 400 pushed two stops with a 200mm telephoto lens and exposed his shot 10 minutes. AOL Image

TVS presents

What: April general meeting
When: April 26 at 7:30 pm
Who: Stuart Marshall
Where: Unitarian Universalist Church in Livermore, 1893 N. Vasco Rd.

Stuart Marshall is a Lawrence Livermore National Laboratory project scientist working on MACHO research. He will address the club on the latest findings related to MAssive Compact Halo Objects.

Dark Matter candidates like MACHOs and WIMPs (Weakly Interactive Massive Particles) have been the subject of intense study at Lawrence Livermore for more than three years. MACHOs were first announced as detected in September 1993, and a dramatic sighting was confirmed in May 1994. A year ago, the Lawrence Livermore team published its research in Physical Review Letters.

The program will allow plenty of time for your questions about how the hunt for Dark Matt er might reshape our concept of the Milky Way and its structure. Please invite any non-members you believe are interested in this topic.

The Dark Site Observatory key exchange continues

A new lock has been installed at the gate leading to the Sky Shack at The Dark Site. Through the May general meeting, your old key may be exchanged for the new one. During this transition period, the old and new locks are linked in series, so you will not be locked out at any time. On page 5 the Star Party Etiquette is reprinted with updates. Please read it carefully, as it describes expected conduct on the observing hill.

The TVS The Dark Site User Agreement is printed on page 7. In order to exchange your key, you must sign a new agreement. It is the same as the one you signed last time. If you do not have a key, and would like to obtain one, your User Agreement must be accompanied by a $20 key deposit. The fee will be returned if you choose to surrender your key at a later date.

Members who cannot attend a general meeting may send a completed User Agreement (and a deposit if required) to key coordinator Al Smith at 120 Bayona Dr., Santa Cruz, CA 94506-3326. You can also reach Al by e-mail: Any other club officer (listed below) can also help you during the key exchange.


April general meeting
Club calendar
Club news notes
What's Up in April
Comet Comments
Star Party Etiquette
The Dark Site User Agreement
Membership renewal

Delinquent members:

This is your final newsletter unless you send or bring a 1996 renewal!

In Memoriam
We note with great sadness the passing of Joe Disch. Joe was an enthusiastic member who attended nearly every general meeting. He was also a fixture on the observing hill, and had a great reputation for sharing his scope and his knowledge. Joe passed away last month due to a heart condition.

His widow Sybil remains a member, and would appreciate any notes of rememberance you would like to send. Her address is:
Sybil Disch
927 Santa Lucia Drive
Pleasant Hill, CA 94523.

ASP sets its 1996 annual conference dates
The 108th annual meeting of the Astronomical Society of the Pacific will be held in Santa Clara from June 21 through 26. It will feature sessions for the general public, amateur astronomers, and teachers at all levels who are interested in astronomy curricula. All sessions are open to the public, subject to a modest admission fee.

"Universe '96" is presented as a cooperative venture between ASP and Astronomy magazine. More than 20 prominant astronomers will speak on such topics as: the Gallileo Jupiter probe, possible planets orbiting other stars, archaeoastronomy, Comet Shoemaker-Levy's impact with Jupiter, and the death of stars.

Tours of Lick Observatory and NASA-Ames Research Center, including the wind tunnel and Kuiper Airborne Observatory, can be arranged.

Project ASTRO is hosting a one-and-a-half day workshop on astronomy in the classroom for elementary grades. A two-day session will focus on teaching astronomy to older children. Community college ins tructors also have a workshop of their own.

For more information contact ASP at (415) 337-1100 or e-mail Lonny Baker:, giving your full postal address. The ASP Web site is

Club Calendar
General meetings
May 24 September 27
June 28 October 25
July 26 November 22
August 23 December 20

Open house at The Dark Site
April 20, meet at Mines Rd. at 6:30 pm. (This is a time change from the last newsletter.)

Bay Area Astronomical Auction and Swap Meet May 4, Swap Meet from noon to 3 pm, Auction starts at 4 pm, Hogue Park, San Jose. Take Highway 17 to Camden Ave. (North) to Bascom Ave. (East). Left on Woodard Ave. Right on Twilight. Follow the signs to Hogue Park. A 10 percent commission fee (to a maximum of $50 per item) is payable to SJAA. Call Robert Brauer at 408 /559-1221 for consignment details.

Northern California Historical Astronomy Luncheon & Discussion Association May 11 at Chabot Science Center Call Norm Sperling (510) 547-6523.

Dave Anderson
(510) 661-4249

Earl Mack
(510) 828-1414

Vice President
Bob Braddy
(510) 855-0964

Gene Nassar
(510) 462-5986

Observatory Director
Chuck Grant
(510) 449-1500

Eyes on the Skies BBS
Mike Rushford
(510) 443-6146

Web Site

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
PO Box 2476
Livermore, CA 94551

Membership: 99

What's Up in April

by Dave Anderson


17 Wed New Moon 3:49 PM Partial solar eclipse visible in New Zealand.
18 Thu Asteroid (2) Pallas at opposition (mag. 8.2).
19 Fri Mercury 5° north of Moon.
20 Sat Astronomy Day.
Open house at The Dark Site. Meet at the corner of Tesla and Mines Road, Livermore, at 6:30 PM
Ganymede eclipsed by Jupiter 2:09 AM Io emerges from transit 2:22 AM Callisto's shadow begins
crossing Jupiter 3:47 AM
Moon in Hyades. Venus 9° north of Moon. (Set about 10:45 PM)
22 Tue Mercury at greatest eastern elongation (20° ). Best evening apparition of the year for northern latitudes.
25 Thu First Quarter Moon 1:40 PM
26 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 ).
Moon occults 6 Leonis (mag. 5.3) about 10:30 PM
29 Mon TVS Planning Meeting 7:00 PM Rich Green's, 4741 Appletree Common, Livermore.
(Call 449-2190 for information or directions.)


3 Fri Full Moon 4:48 AM PDT.
4 Sat Venus at greatest brilliancy (mag -4.5).
5 Sun AANC Meeting 1:00 PM Lawrence Hall of Science, Berkeley.
Venus at greatest northern declination (+27° 47') in the 20th century.
8 Wed Jupiter 5° south of Moon. (Ri se about 12:30 AM) Later Neptune is 5°, then Uranus 6° south of Moo n.
Moon occults Comet Hale-Bopp about 3:00 AM
9 Thu Last Quarter Moon 10:04 PM
11 Sat Asteroid (4) Vesta at opposition (mag. 5.6).
Good weekend for observing: no Moon until after 1 AM
12 Sun Europa transits Jupiter 12:04 to 2:50 AM, preceded by shadow, which egresses at 12:41 AM
Io eclipsed 1:51 AM
13 Mon Saturn 3° south of Moon. (Rise about 4 AM)
17 Fri New Moon 4:46 AM Excellent weekend for observing.
18 Sat Asteroid (372) Palma occults SAO 117650 (mag. 8.7, R.A. 9h23.7m, Dec. +8° 38') 9:54 PM
in or near Bay Area. Max. duration: 9 sec.
19 Sun Venus 8° north of Moon.
22 Wed Pluto at opposition (mag 13.7).
24 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).

Some springtime deep-sky objects

M44 The Beehive cluster or Praesepe in Cancer. Beautiful in binoculars.
M81 & M82 Two fine galaxies in Ursa Maj or. The first a fine spiral; the second irregular, elongated with a dark band running throught it.
M97 & M108 The Owl nebula and a nearby galaxy. M97 is a large, somewhat faint planetary in Ursa Major.
M65 & M66 Two nice galaxies in Leo with the large, fainter, edge-on spiral NGC 3628 in the same field.
M95, M96 & M105 A triplet of galaxies less than a degree apart in Leo.
M51 The Whirlpool galaxy in Canes Venatici. One of the best galaxies in all the sky. Peculiar appendage NGC 5195.
M3 A fine globular cluster in Canes Venatici.
NGC 3242 The Ghost of Jupiter in Hydra. A nice planetary.

Comet Comments, April 1996

C/1995 Y1 (Hyakutake)
DATE (00UT) R.A. (2000) DEC El. Sky Mag
04-17 22h25.6m +30° 53' 50° M 10.1
04-22 22h38.8m +31° 53' 50° M 10.3
04-27 22h51.1m +32° 47' 51° M 10.5
05-02 23h02.5m +33° 35' 52° M 10.7
05-07 23h13.1m +34° 18' 53° M 10.9

C/1996 B1 (Szczepanski)
DATE (00UT) R.A. (2000) DEC El. Sky Mag
04-17 09h20.7m -12° 56' 116 ° E 10.0
04-22 09h21.0m -14° 51' 112 ° E 10.3
04-27 09h22.3m -16° 31' 109 ° E 10.6
05-02 09h24.5m -17° 59' 106 ° E 10.8
05-07 09h27.5m -19° 19' 102 ° E 11.1

C/1995 O1 (Hale-Bopp)
DATE (00UT) R.A. (2000) DEC El. Sky Mag
04-17 19h45.0m -18° 26' 93° M 8.0
04-22 19h45.1m -18° 03' 97° M 7.9
04-27 19h44.7m -17° 40' 102 ° M 7.8
05-02 19h43.8m -17° 16' 107 ° M 7.7
05-07 19h42.6m -16° 52' 112 ° M 7.5

DATE (00UT) R.A. (2000) DEC El. Sky Mag
04-17 18h04.3m -16° 36' 116 ° M 9.5
04-22 18h13.0m -16° 28' 119 ° M 9.2
04-27 18h21.5m -16° 19' 122 ° M 8.7
05-02 18h29.5m -16° 10' 125 ° M 8.5
05-07 18h37.2m -16° 02' 127° M 8.3

C/1996 B2 (Hyakutake)
DATE (00UT) R.A. (2000) DEC El. Sky Mag
04-17 02h55.0m +35° 47' 30° E 2.1
04-22 02h47.4m +32° 29' 23° E 1.3
04-27 02h37.0m +27° 59' 15° E 0.1
05-02 02h25.9m +20° 52' 6° E -0.3
05-07 02h21.7m +12° 19' 10° M 0.8

by Don Machholz

Five comets are visible in our skies this month. One - Comet Hyakutake (C/1996 B2) - is the brightest comet in 20 years! In late March it passed near the Earth. As it continues in toward the Sun it will remain a unaided-eye object, sporting what should be a fairly bright tail in the evening sky. By mid-April it will be low in the western sky after sunset. Two of the tables below give positions for the comet, one for every 5 days and one for every half-day. The positions given are for Universal Time. Observers in the United States searching for the comet on the evening of, for example, April 22nd, will find it near the position given for April 23rd, or even slightly later. The same table also gives the position angle of the tail if it points directly away from the Sun. This is represented by degrees, with north equaling 360 deg., east is 90 deg., south is 180 deg., etc. Finally I give the distance from the Earth in millions of miles.

The first Comet Hyakutake (1995 Y1) remains in the morning sky while Comet Szczepanski fades in the evening sky. Periodic Comet Kopff brightens in the southern morning sky, it nears Comet Hale-Bopp in June.

Orbital Elements

Object Hyakutake(95Y1) Szczenpanski Haykutake(96B2)
Peri. Date 1996 02 24.28973 1996 02 06.89903 1996 05 01.40305
Peri. Dist (AU) 1.054576AU 1.4486192AU 0.23014060AU
Arg/Peri (2000): 46.35126 deg. 151.27225 deg. 130.18992 deg.
Asc. Node (2000): 195.75924 deg. 345.44413 deg. 188.05114 deg.
Incl (2000) 54.46584 deg. 51.90616 deg. 124.90012 deg.
Eccen: 1.0 0.9899357 0.9998449
Orbital Period: Long Period 1727 yrs. 57,000 yrs.
Ref: MPC 26543 MPEC1996-C02 MPC 26724
Object Hale-Bopp Kopff
Peri. Date 1997 04 01.12081 1996 07 02.19980
Peri. Dist (AU) 0.9141160AU 1.5795617AU
Arg/Peri (2000): 130.58985 deg. 162.83487 deg.
Asc. Node (2000): 282.47097 deg. 120.91329 deg.
Incl (2000) 089.42765 deg. 4.72143 deg.
Eccen: 0.9951019 0.5440739
Orbital Period: 3000 yrs. 6.45 yrs.
Ref: MPC 26723 (2-24) MPC 22032 (1991)
I have just finished writing an 82-page book for those wishing to make the most of Comet Hale-Bopp's visit to our skies. Containing 64 maps and 21 figures, it prepares both the beginner and the seasoned astronomer for the comet. Entitled An Observer's Guide to Comet Hale-Bopp, it is available by sending $12.00 plus $2.00 shipping and handling to
MakeWood Products
P.O. Box 1716
Colfax, CA. 95713.
For first class mail the S&H totals $3; for overseas air mail it is $6. Phone orders, using a credit card, are accepted at 916-346-8963.

TVS Star Party Etiquette

Pay $3 per car at entry for each visit to The Dark Site. Put this money into the slotted box mounted on the post located to the south of the owner's house.

Be sure to bring adequate food, water, and clothing. It's always hotter/colder than you anticipate, and it's a long way back to town. Facilities at the Sky Shack are primitive (no water, out-house). Bring your own toilet paper.

Lock the gate when entering or exiting the observing hill. Leave the Mines Rd. gate and combination lock in the same condition as you found them.

No white lights! Be they headlights, flashlights, vehicle running lights, vehicle interior lights, flash cameras, or whatever, white lights should be used only in emergencies. Arrive early (before dark) so you don't have to use your headlights at the site. Use the minimum light necessary to see, if you arrive late.

Always assume someone is taking a time-exposure photograph. Walk up the hill and check before you drive up. Turn off, remove, or cover your vehicle's interior lights. All flashlights should have a red filter and be of low intensity.

Parking: If you plan to stay all night, park away from the exit. If you are leaving early, park near the exit, and park so that you will not have to back up. (Backup lights are white!) If you must leave, please ask if anyone is taking a photograph. Wait until the exposure is finished before you leave.

Always ask before you use or move any one else's equipment; including club equipment.

No loud noises: This includes loud music, loud conversations, etc. Most observers are there to soothe their nerves, not to rattle them!

Open fires are prohibited at The Dark Site all year long. Barbecues, hibachis, etc. are not allowed to due to the lack of water to quench them.

No smoking in the observatory or near telescopes. Smoke damages the optics. If you must smoke, do it only in your vehicle and keep cigarette butts in the ashtray.

Litter: If you brought it with you, take it with you. Leave the site a little cleaner than when you got there.

No alcoholic beverages are permitted on the observing hill.

Please remember that these guidelines pertain during any TVS use - open houses, star parties, or private observing sessions. Our continued ability to lease the site is dependent on your adherence to those guidelines protecting the club and the land owner. Thank you for your help in upholding them.


Club Calendar
School star party

May 22 at Donlon School in Pleasanton, 7 pm. Bob Braddy will be recruiting volunteers.

Riverside Telescope Makers Conference (RTMC) May 24-27 at YMCA Camp Oakes east of Big Bear City. To receive a registration form call (909) 948-2205, leaving your full mailing address.

Yosemite Star Parties June 21-23 (first quarter Moon) August 30-September 2 (Labor Day weekend, waning gibbous Moon) Yes, we have two dates this year! By agreeing to the Labor Day weekend party, we hope to secure a New Moon date for next year.

White Mountains Star Party at Barcroft Lab August 15-19 (Just following new Moon, and the warmest time of year for this high-altitude site.) Dave Rodrigues is club coordinator for this popular annual even.

Editor's Note

The new cartoon strip "Starman" is reprinted below courtesy of amateur cartoonist/astronomer Jay Ryan. Jay observes in Cleveland, Ohio. Please let the board know if you want to see this feature continued in Prime Focus.

See Don Machholz's announcement of his book on Comet Hale-Bopp,

Tri-Valley Stargazers Astronomy Club User Agreement for The Dark Site

The Tri-Valley Stargazers Astronomy club leases a hilltop from the owner of The Dark Site for astronomical viewing and astrophotography. This site is available to all dues-paying club members. A key and a photocopy of this signed agreement will be returned to each user upon acceptance of his or her application.

In exchange for the opportunity to use this site I agree to:

Pay a refundable deposit of $20 for use of a key to the observing hill gate. The key is the property of the Tri-Valley Stargazers Astronomy Club, is not transferable and may not be duplicated. Deposit will be forfeited if membership dues are delinquent more than 6 months.

Pay $3 per car at entry for each visit to The Dark Site. I will put this money into the slotted box mounted on the post located to the south of the owner's house.

Leave the observing hill gate closed and locked, and leave the Mines Rd. and all other gates at The Dark Site in the same condition as I found them.

Conduct myself with proper etiquett e so as to respect the rights of other users at the site.

Accompany any guests I bring, and be fully responsible for their actions while at the observing site.

Relinquish the key if I do not renew my yearly membership in the Tri-Valley Stargazers Astronomy club, or upon demand by a Club Officer.

By my signature below I show that I have read and understood the above conditions. I understand the failure to comply with any of these conditions may result in revocation of my privileges.


Print Name______________________________________________________


Make checks payable to: Tri-Valley Stargazers, and bring to the April or May 1996 general meeting;

or send to: Tri-Valley Stargazers
P.O. Box 2476
Livermore, CA 94551.

Mines Rd. Combination Number_____________________

Key Number__________________________________________ Date Issued___________________________

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