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PRIMEFOCUS 2002 Tri-Valley Stargazers September September Meeting Mirror testing: An overview of amateur mirror testing techniques with an in depth look at the new lateral wire test Meeting Info: OR What So you want to test a mirror… So you want to test a mirror… Figure 1 Who John Swenson John Swenson Amateur mirror testing is a bit of a black art. Many books describe it, but no matter how When many books you read, actually performing September 20, 2002 the test is a surprise. This talk will actually Conversation at 7:00 p.m. perform several of the common mirror tests Lecture at 7:30 p.m. with what you see projected on a TV screen so you can get a “feel” for what it’s like to Where squint at fleeting shadows. Unitarian Universalist I will go into detail on the new “lateral wire Church in Livermore test”, a very simple test that is MUCH easier 1893 N. Vasco Road to perform than the others, and is valid for a Figure 2 much broader range of mirrors. I’ll run a mirror or two through the process and come Inside up with a surface error chart for them. Hopefully this presentation will demystify the News & Notes 2 art of mirror testing enough so that some of Calendar of Events 2 you will dive in and make your own mirror. Star Parties 5 Astronomical Insights 5 Figures 1-3 What’s Up 6 The images on the right show three different types Membership/Renewal of mirror testing. Note that these test images are not from the same mirror. Figure 1 is the ronchi Application 8 test, Figure 2 is the foucault test, and Figure 3 is the new lateral wire test. Figure 3 News & Notes New Members Money Matters Next time you see them at the meeting, say hello to our At the August Board meeting, Treasurer Mike Anderson two new members, Stan Isakson and Tom Kozon. reported the balances (as of August 19, 2002) of the fol- lowing TVS accounts: 2002 TVS Meeting Dates Checking $1,149.16 CD #1 $3,882.06 matures 11/17/02 Below are the remaining meeting dates for 2002. The CD #3 $2,395.77 matures 11/27/02 lecture meetings are held on the third Friday of the CD #4 $2,039.04 matures 10/16/02 month, with the Board meeting on the Monday follow- continued page 7 ing the lecture meeting. The Prime Focus deadline applies to that month’s issue (e.g., the October 6th deadline is for the October issue). Calendar of Events Lecture Board Prime Focus Meeting Meeting Deadline Classic Sci-Fi Film Series Sep. 20 Sep. 23 Sep. 8 Chabot Space & Science Center Oct. 18 Oct. 21 Oct. 6 The movies are shown at the Tien MegaDome Theater. Nov. 15 Nov. 18 Nov. 3 Tickets are $5 per person and are available at the door, at Dec. 20 Dec. 16 Dec. 8 TicketWeb.com, or the Chabot Box Office, 510-336-7373. Movies: We do not have a speaker lined up for October just yet, Indiana Jones and the Temple of Doom, October 4 – 6 but our November speaker is Deanna Pennington who Indiana Jones and the Last Crusade, November 1 – 3 will speak on the Keck wave front correction systems. Our December meeting will be our Winter Solstice Potluck. 2001: A Space Odyssey, December 6 – 8 Showtimes: Friday – Sunday on the first weekend of each month. Comet Hoenig Fridays – 7:30 p.m. Comet Hoenig is now around 7.5 magnitude in the Saturdays – 4:00 & 7:30 p.m. north circumpolar sky. It will reach perihelion (its closest Sundays – 4:00 p.m. point to the Sun) around October 1st. The map below shows it path from now through September 30th. The Ends September 15 first number is the date in September, the second number What: The Lost Spacecraft: Liberty Bell 7 Recovered is the time in UT. So the first number you see–10:21 Where: Chabot Space & Science Center UT–means September 10th at 21:00 UT (9:00 PDT). Cost: General Admission price All plot positions are for 21:00 UT/9:00 PDT. Newsletter header image: Semeis 147: Supernova Remnant. Seen towards the constellation Taurus it covers nearly 3º (six full moons) of the sky corresponding to a width of 150 light- years at the stellar debris cloud's estimated distance of 3,000 light-years. On three separate nights in December 2001 and January 2002 astronomer Steve Mandel accumulated a total of over eight hours of exposure time to compose this image. He used an astronomical CCD camera, telephoto lens, and his specially designed adapter to allow such wide-field digital imaging. He also used a narrow H-alpha filter to transmit only the the light from recombining hydrogen atoms in the expand- ing nebulosity, defining the regions of shocked, glowing gas. This supernova remnant has an apparent age of about 100,000 years (light from the original explosion first reached Earth 100,000 years ago) but it is not the only aftermath of the mas- sive stellar explosion. The cosmic catastrophe also left behind a spinning neutron star or pulsar, all that remains of the star's dense core. Credit & Copyright: Steve Mandel 2 Calendar of Events continued The Liberty Bell 7 exhibit is quickly coming to an end. If Dr. Vakoch researches ways that different civilizations you want to see the actual spacecraft that had sunk to the might create messages that could be transmitted across bottom of the ocean in 1961 and was retrieved 38 years interstellar space, allowing communication between later, you’ll need to get over to Chabot by Sunday the humans and extraterrestrials even without face-to-face 15th of this month, as the exhibit will be gone the next contact. He is particularly interested in how we might day. This is a really neat (and large) exhibit, so if you compose reply messages that would begin to express haven’t already made the trip I highly recommend a visit. what it’s like to be human. His current project in inter- stellar message composition focuses on communicating September 17, 7:30 p.m. concepts about the evolution of altruism, as seen from What: The Substellar Zoo sociobiological, evolutionary psychological, and philo- Who: Dr. Gibor Basri (UC Berkeley) sophical perspectives. Dr. Vakoch is a clinical psychologist Where: Morrison Planetarium, San Francisco with a training in comparative religion. Cost: $3 September 22, 3:00 p.m. The Fall Dean Lecture Series at the Morrison Planetarium What: COSMOS 1: Attempts to Fly the First Solar Sail starts off with Dr. Gibor Basri, who will be talking about Spacecraft the surprising picture of brown dwarfs and giant planets Who: Louis D. Friedman (Executive Director, The based on their observed numbers, masses and orbits. Planetary Society) Advance ticket purchase is recommended. You can send a Where: Morrison Auditorium, Cal. Academy of Sciences self addressed stamped envelope (SASE) and check Golden Gate Park, San Francisco payable to Morrison Planetarium to: Cost: $3 advanced, $5 at the door. Dean Lecture Series, Morrison Planetarium The Planetary Society Bay Area Volunteer Network and California Academy of Sciences the Morrison Planetarium of the California Academy of Golden Gate Park Sciences present this talk by Louis Friedman. San Francisco, CA 94118 To order your tickets in advance, send a check payable to For more information you can reach the Dean Lecture The Planetary Society, and a SASE to: Info line at 415-750-7141. X-Environs c/o Barbara Raskin September 19, 7:30-9:00 p.m. 1530 Bay Laurel Dr. What: The Art & Science of Interstellar Message Making Menlo Park, CA, 94025. Who: Dr. Doug Vakoch (Interstellar Message Group, Orders received after September 15, or without a SASE, SETI Institute) will be held at Morrison Auditorium. Tickets are limited Where: Chabot Space & Science Center and non-refundable. Cost: $5 continued next page Officers Kelley, Signe McIntire, Dave Webmaster: Lecture Meeting: President: Rodrigues, Frank Rogue, Mike Chuck Grant Unitarian Universalist Church Chuck Grant Rushford, Debbie Scherrer, Observatory Director/ 1893 N. Vasco Road, Livermore [email protected] John Swenson, Norm Thomas, Key Master: Phil Waide Board Meeting: 925-422-7278 Chuck Grant Round Table Pizza Vice-President: Volunteer Positions School Star Party Chair: 1024 E. Stanley Blvd., Livermore Rich Green (unofficially) Gary Steinhour Librarian: [email protected] Web & E-mail [email protected] Jim Alves 925-449-2190 Treasurer: [email protected] www.trivalleystargazers.org Mike Anderson 925-634-0220 Public Star Party Chair: [email protected] Roger Gathers [email protected] Newsletter Editor: 925-455-6039 Eyes on the Skies Secretary: Debbie Dyke Maggie Halberg [email protected] Historians: Eyes on the Skies is a robotic 925-736-8627 925-461-3003 Paul Caswell & Debbie Dyke solar telescope run by Mike Rushford (rushford@eyes-on- Program Director: unfilled Board of Directors Addresses the-skies.org). You may access Alane Alchorn, Jim Alves, Dave Loaner Scope Manager: Mailing: it by visiting www.eyes-on-the- Anderson, Dennis Beckley, Paul John Swenson Tri-Valley Stargazers skies.org. Caswell, Rich Combs, Debbie [email protected] P.O. Box 2476 Dyke, Gert Gottschalk, Kathleen Livermore, CA 94551 3 Calendar of Events continued On the web, visit The Planetary Society at http://plane- MTIA Astronomy Programs tary.org and The Bay Area Volunteer Network at c/o Tinka Ross www.tpsbavn.org. For directions to the California 89 Dominican Drive Academy of Sciences, call 415-750-7144. San Rafael, CA 94901. Parking is limited, so car pooling is encouraged.