San Diego Astronomy Associationdocs.sdaa.org/Newsletters/2006-05.pdfally,” Alice admits. “But, I made sure I knew something about what I was showing (M42). I spent the entire two

San DiegoAstronomy AssociationCelebrating Over 40 Years of Astronomical Outreach

Offi ce (619) 645-8940Observatory (619) 766-9118http://www.sdaa.orgA Non-Profi t Educational AssociationP.O. Box 23215, San Diego, CA 92193-3215

May 2006

SDAA Business MeetingNext meeting will be held at:

Teledyne RD Instruments USA9855 Businesspark Avenue

San Diego, CA, USA 92131-1101May 9th at 7:00 pm

Next Program Meeting Science Fair Project and New

Horizons PresentationsMay 17th at 7:00 pm

Mission Trails Regional Park Visitor and Interpretive Center1 Father Junipero Serra Trail

May 2006 Vol XLII, Issue 05Published Monthly by the San Diego Astronomy Association75¢ /$8.00 yearIncorporated in California in 1963

Members at Large Needed ..........................1Outreach Outlook .........................................1May Program Meeting...................................3Radio Astronomy..........................................3Night Sky Network........................................3Board Minutes........................................5May Calendar ........................................6June Calendar ......................................7Sky Watch ....................................................8Spring Cleanup.........................................9Treasurer’s Report ....................................9Who Wants to be a Daredevil?...............10AISIG Gallery.............................................11The Back Page...........................................12

CONTENTS

Members-At-Large Neededby Brian V. Staples

Over the years, we have grappled with the problem of attrition of members. Infor-mal studies show that approximately 80-85% of the members that dropped out did so after being in the club for only a year. A person joins the club, gets their membership package, but after that, unless they are highly motivated, they have no other interac-tion with the club. After a year passes, without contact with the club, they either forget to renew their membership or choose not to. They may feel they got very little for their dues, and hence why should they renew? We have put some measures in place to help these new and near new members: the new member packet, a call welcoming them to the club, and when they do not renew, a call to remind them their renewal is due. We also have some other programs, such as the TDS orientation tour. However, in between, there is little contact with these members; unless, as I mentioned, they are motivated enough to come to meetings, Stars in the Park, TDS, and other club events. What is needed for those who may be to shy or reclusive to attend events or otherwise become involved, is for them to have someone that can comfortably contact to answer questions and guide them through the benefi ts of the club. As part of the process to quell this attrition, we have discussed the idea of “mem-bers-at-large.” While this term holds varied meanings in different organizations, we want to use it to mean veteran members who help other members with club issues. These would be positions in the club that are not Board position, but rather fi lled by a small group of veteran members who would be willing to be there for members to answer their questions about the club, our facilities, observing and equipment, basi-cally, all things hobby related. We will publish contact information for the Members-At-Large in the new member packet, in the newsletter, on the web site, and in the Yahoo and SDAA Forums. Any member, especially new members, could call on a Member-At-Large to answer their questions. We need about six members to volunteer for this vital role. That’s 1% of the club membership! If you would like to serve as a Member-At-Large, please call me at (858) 560-9064 or e-mail me at [email protected] and we can discuss how you can take part in ushering in new members to, and assisting all members of our club.

Outreach Outlookby Mark Smith

This month, I thought it would be nice to start introducing some of the people who make our outreach efforts possible. While seeing the Moon or Saturn through a telescope really speaks for itself, somebody still has to get the telescope to the star party, set it up, help people to look through the telescope, and answer any questions. Alice Harvey dislikes being the center of attention. In fact, her response when I told her that I’d like to feature her in this article was, “Well, better to get it over fast.” Alice started playing with astronomy about 10 years ago in an attempt to fi nd something that might interest her daughter. The bug didn’t catch in the young Miss Harvey, but it caught in Alice and she joined SDAA that same year. It has only been

Continued on Page 2

San Diego Astronomy Association

Page 2 SAN DIEGO ASTRONOMY ASSOCIATION NEWS AND NOTES, APRIL 2006

in the last year and a half that she has been active with the outreach program. So, how does somebody who dislikes being the center of attention react to their fi rst star party? “I was terrifi ed, actu-ally,” Alice admits. “But, I made sure I knew something about what I was showing (M42). I spent the entire two hours on M42, telling over and over about the nebula and Orion and starbirth. By the end of the night I realized that it wasn’t too hard.” Then came the looks on the kids’ faces and the “oh my gosh” exclamations of discovery and Alice was hooked. “The fi rst time a 10-year old looks thru your telescope and says ‘awe-some!” – that’s it.” Alice arrives with her 10” Newtonian Dob and is usually one of the fi rst people to be ready to go. As she’s not very comfortable approaching people she doesn’t know, she treats outreach sessions as ice breakers and, because she uses a dob which requires frequent adjusting, she even gets some viewing in herself. After having done several events, she plans out like-ly objects to show in advance and comes prepared to answer the most basic questions (“How far away is it?” type questions). Her favorite question is, are you a scientist? “That’s always the funny one to me - the English major,” Alice admits. The bonus time under the stars is a plus as well. “I get to set up and observe for a couple of hours, without a long drive, and am usually home within 20 minutes,” she says. “Although I don’t spend the time at the eyepiece myself, I get to keep looking (and adjusting my scope) and talking about something I love. Plus I can tell people what a cool club the SDAA is.” After a star party, there are a lot of people who think Alice is pretty cool too. If you are interested in volunteering at a Star Party, check the calendar on the Yahoo! Group (http://groups.yahoo.com/group/sdaa/cal) or contact one of our Star Party Coordinators (Bob Nanz (760-751-3992 ) in the North County, Don Hamm (858-453-7413 ) in the Central County, Joshua Johnson (619-403-3651) in the South County, Rich Strobel (619-479-3937) in the East County, and Jose Magsaysay (858-752-1029) for the Midway). Let’s see how many people we can introduce to the wonders of the universe this year!

Continued from page 1

SDAA Outreach 2006Events Held Events

CancelledVolunteer

HoursScopes

DeployedPeople

ReachedJanuary 21 0 352 102 2279February 19 4 258 105 1802March 20 10 347 114 3710Total 60 14 957 321 7791

Volunteer – obsolete French voluntaire (now volontaire), from Latin voluntaries; n. 1. A person who performs or offers to perform a service voluntarily. 2. A person who does something, es-pecially helping other people, willingly and without being forced or paid to do it. v. 1. To perform or offer to perform a service of one’s own free will. 2. To offer to do something that you do not have to do, often without having been asked to do it and/or without expecting payment.


Page 3SAN DIEGO ASTRONOMY ASSOCIATION NEWS AND NOTES, APRIL 2006

May Program Meeting

Three members attended the Greater San Diego Science and Engineering Fair to judge the middle and high school entries. They found four projects that they considered really great. We’ve asked these four participants to bring their projects to the May Program Meeting and present them to the member-ship. For their hard and outstanding work, we will be present-ing each with a cash prize and a membership to the SDAA. These four young people are: Jacob Rucker - Polluting Palo-mar: Effect of Sky Glow on Stellar Visibility, Year III; Calvin Ridenour - Star or Satellite, Which is Better? (GPS v. stellar navigation); Jen Lee - Asteroid Attack (effect of impact angle on ejecta); Adori Yabut - Eureka! Stellar Parallax Really Works. Jerry Hilburn will be giving his JPL presentation on New Hori-zons, Journey to Pluto. The meeting schedule is as follows:May – Science Fair Winner Jerry Hilburn, New Horizons, Journey to PlutoJune – Gary Peterson, The Problem with PlutoJuly – OpenAugust – Kathy Boyd, Radio Astronomy

Radio Astronomy Some of you may already have an understanding of things technical and electrical. For the rest of us, I include the refer-ences! Everyone is invited to share discussion and information at the RASIG yahoo group.

Dishing on Antenna Anatomy A mainstream icon of Radio Astronomy (RA) is the para-bolic dish antenna. The antenna is to a radio telescope what mirrors are to an optical refl ector telescope. In an optical refl ector telescope, the primary mirror collects electromagnetic spectrum frequency stuff (visible light). In RA, the parabolic dish collects electromagnetic spectrum frequency stuff (invisible light). In an optical refl ector telescope, the stuff may be refl ected from the primary mirror to a secondary mirror. In a radio dish antenna, the stuff may be refl ected from the parabolic dish to a subrefl ector (Gino, 2001). In an optical refl ector telescope, the stuff may go from the secondary mirror to a focuser and eyepiece for interpretation by an eyeball. In a parabolic dish antenna, the stuff may go from the subrefl ector to a feed horn. From the feed horn, gad-gets like amplifi ers, mixers, oscillators, detectors and recorders are used to process and demonstrate the stuff visually and/or audibly. There are variations of design found in optical refl ector

telescopes, and this is also true for parabolic dish antennas. A dish antenna might use a subrefl ector, as in the Cassegrain feed system already described, or, a dish may have a Focal Feed point system with a dipole element (for lower frequencies) or a circular waveguide (for higher frequencies) at the focal point (“The Parabolic Refl ector,” n.d). Antennas used in RA come in a wild variety of shapes and sizes! A few common ones, besides the parabolic dish, are: Dipole, Yagi, Corner Refl ector, Helical and Horn (Lichtman, 1997). Information about these types of antennas and exam-ples of their applications may be presented in a future article and/or program meeting. The Small Radio Telescope (SRT) that Mr. Aburto donated to the SDAA includes a 10ft parabolic dish antenna that we can use to map the sky! Brian Staples transported it to TDS and it will be assembled and positioned near RoboScope. If you would like to be a part of this exciting project, let it be known on the RASIG yahoo group at http://groups.yahoo.com/group/SDAA_RASIG/.

References Gino, C. (2001). Anatomy of An Antenna. Retrieved April 20, 2006, from http://www.astrophys-assist.com/educate/anatomy/antenna.htm. Lichtman, J.M. (1997). Amateur Radio Astronomy Systems, Procedures, and Projects. Roswell, GA: Radio Astronomy Supplies. The Parabolic Refl ector Antenna. (n.d.). Retrieved April 20, 2006, from http://www.radio-electronics.com/info/antennas/parabolic/parabolic_refl ector.php.

NASA’s Night Sky NetworkAn Astronomer’s Atmosphere

So far this article has taken us from the Sun to the ends of the observable universe. This month, I’d like to deal with something a little closer to home; our atmosphere. As amateur astronomers, we have a love-hate relationship with the atmo-sphere. Generally, we hate it. We complain about dew, fog, seeing, and any number of other things. On the other hand, we like the warmth that our atmosphere evenly distributes around the planet and we have become rather fond of breath-ing. Despite this relationship we have with our atmosphere, many of us don’t have a clear picture of it. The atmosphere is a very dynamic place and is much more complex than most of us realize. Most of us assume that, since space is very cold and because it gets cooler as we gain altitude, the atmosphere gets progressively cooler as we go higher. The truth is much more complex. Up to an altitude

Continued on Page 4



of about 7.5 miles, the temperature in the atmosphere does decrease steadily to about -73 °F. Between 7.5 and 12.5 miles, the temperature remains approximately the same and between 12.5 and 30 miles, the temperature steadily increases until it reaches about 35 °F. From here, there is another short zone where the temperature remains essentially unchanged before it decreases to about -118 °F at 53 miles. From 53 to 59 miles, there is another zone of relatively constant temperature before a steady increase in atmospheric temperature to about 190 °F at 75 miles. Above this altitude, the atmosphere is so thin that air temperature is not meaningful. That is a lot of information that is mostly not meaning-ful to us other than to point out that the atmosphere is very complicated and we shouldn’t be surprised that it is sometimes hard to see through. It doesn’t really help us to visualize, or explain, our atmosphere. Fortunately, NASA has scaled this all very nicely for us and has even provided us with a very good method to demonstrate the effects of our atmosphere using nothing more than a 12” beach ball (you can often fi nd 12-14” infl atable globes that work extremely well for this purpose), a piece of paper, and some bubble wrap (the kind with the small bubbles). Most people don’t realize that 80% of our atmosphere, and all of our weather, is limited to the bottom 10 miles. On the

2,500 Mile Diameter Galaxy (Quarter Sized Solar System)Star Name Distance DSO Name Distance Diameter

Spica 6.6 miles M3 830 miles 4.5 milesArcturus 1 mile M5 612 miles 4.1 miles

Vega .6 mile M13 625 miles 3.5 milesDeneb 37 miles M53 1450 miles 5.5 milesAlberio 10 miles M57 60 miles 40 yards

Newsletter DeadlineThe deadline to submit articles

for publication is the15th of each month.

SDAA Editorial StaffEditor - Mark [email protected] Writers

Bob AustinBrian Staples

Lou N. JacksonKatherine Boyd

Alice HarveyJohn MoodMark Smith

Patrick L. BarryDr. Tony Phillips

scale of our 12” beach ball, this is about the thickness of a piece of paper. The bottom 300 miles of our atmosphere, rep-resented by a sheet of small bubble wrap, has almost all of our atmosphere. Above this altitude, our atmosphere no longer has much effect on orbiting satellites (Hubble is in a 353 mile orbit and the ISS is in a 220 mile orbit). Now, take that bubble wrap off the beach ball and look through it. The view through the bubble wrap is a remark-ably good analogy for what looking through our atmosphere is like. Through the bubble wrap, everything becomes blurred, although if you hold the bubble wrap still, you can still make out some detail through parts of it. This nicely shows the distortion and seeing problems that the atmosphere causes. If you have a light source handy, try looking through the bubble wrap with the light shining on it at an angle. You will see that the refl ection of the light off the bubble wrap makes the im-age cloudier and less distinct, just as light pollution makes our atmosphere harder to see through. Finally, if you look through the bubble wrap at an angle, you will see that your view de-grades, just as it does when you try to view objects close to the horizon. So, the next time you have somebody come up to you at your telescope and ask you why the stars are fl ickering or why Jupiter looks so much better tonight than it did last time, have

Continued from Page 3

Continued on Page 9



April 2006 SDAA Board Meeting Minutes (Unapproved and Subject to Revision)

ATTENDEES:Board: Brian Staples, Bob Austin, Michael Finch, Mark Lane, Brian McFarland, Roy Ang, Ed Rumsey, Alice Harvey, and Lou Jackson.

Members: Carey Johnson, Kathy Boyd, and Susan Austin

1. Reports

MARCH MEETING MINUTES: Approved.

TREASURER’S REPORT: Approved. Insurance renewal approved.

SITE MAINTENANCE:• Barbed wire installation atop the South fence, running part way up the West and East fences, is about 25%

fi nished.• The two loaner pads are prepped, formed, and ready for concrete.• We are considering forming the pad for the refractor adjacent to the club observatory.• We intend to hold another site cleanup for June 3rd – we’ll get a dumpster.• Pay Phone – SBC no longer services them so they’ll hook us up with local support.

OBSERVATORY REPORT: Still need a new motor-start capacitor. The issue is being worked.

PRIVATE PAD REPORT: Waiting list has one member awaiting a pad and one awaiting an upgrade. Radio tele-scope will use pad #3 since nobody wants that pad. The private pad lease agreement was updated, reviewed, and approved.

STAR PARTY REPORT: KQ ranch is scheduled for the summer months. Kin Searcy and Ed Rumsey donated $50 to cover Messier Marathon event costs. Space Day and Astronomy Day will occur on the same day (Saturday, May 6, 2006) – we will cover both.

LIBRARY/EDUCATION REPORT: One item has been returned. SDAA board members Alice Harvey, Randy Marsden, and Brian McFarland judged the GSDSEA Fair in Balboa Park on March 29. The SDAA will provide $150, $100, $50, and $50 respectively to the 1st, 2nd, and 3rd (two tied for 3rd) place winners; they’ll also receive SDAA memberships. Prizes and certifi cates will be presented at the May Program Meeting.

MEMBERSHIP REPORT: Rich Strobel had to drop out of the May meeting, Kathy Boyd will provide a talk on Radio Astronomy at the August Program Meeting, and we still need to fi ll July. Ed Rumsey will present the Messier results at the April meeting.

AISIG REPORT: Monthly meeting will be held on the 4th Wed at Mission Trails – we are confi rmed for April and John LaBorde will present.

RASIG REPORT: A radio telescope has been donated to the SDAA - it will be mounted on undesirable pad #3. Brian McFarland will donate and deliver a large pier for the radio telescope, we’ll need a desktop computer and an enclosure, and we’ll inventory the equipment on the 29th of April.

Continued on Page 9







SkyWatch for May, 2006

John Mood

[ Times PDT]

[ * = 1 star = EZ ] [ ** = 2 stars = Moderate ] [ *** = 3 stars = Diffi cult ]

[ 2 degrees = index fi nger held at arm’s length. ]

Sat., 29 April ---- MEMBERS STAR PARTY @ Tierra del Sol.Fri., 5 May ---- ETA AQUARID METEOR SHOWER peaks this a.m. (N.B.! – That’s before dawn.)Wed., 10 May ---- MOON only 0.3 degree from SPICA.Fri., 12 May ---- FULL MOON, 11:51 p.m.

Sat., 20 May ---- STAR PARTY @ Tierra del Sol.Fri., 26 May ---- NEW MOON, 10:26 a.m.Sat., 27 May ---- MEMBERS STAR PARTY @ Tierra del Sol.Sat., 3 June – PUBLIC STAR PARTY @ Tierra del Sol; good opportunity to observe Mountains, craters & rills at the MOON’s terminator (where dark becomes bright).

EVENING PLANETS:Orangy MARS [ * ] is dim as it leaves Gemini the Twins for Cancer the Crab; by late June, it will be in a straight line

with Castor & Pollux. Yellowish SATURN [ * ] is spectacular in Cancer the Crab, still close to M-44, “Praesepe” (the “Beehive Cluster”). JUPITER [ * ] is in Libra the Scales & is available for good telescopic viewing a couple of hours before midnight.

MORNING PLANETS: Bluish NEPTUNE [ ** ] is in Capricornus the Sea-Goat. Greenish URANUS [ * 1/2 ] is in Aquarius the Water-bearer. VENUS [ * ] crosses Pisces the Fishes into Cancer the Crab & is so bright all you early-risers can easily see it naked eye after dawn breaks.

{ Re Pluto as a non-planet, see my “SkyWatch for September, 2005.” }

OBSERVING HIGHLIGHTS: These nights, URSA MAJOR the Greater Bear is as overhead as it gets, a good opportunity to test your eye-sight. The middle star in the “handle” of the “Big Dipper” is a double star, MIZAR & ALCOR, the Horse & Rider. Those with good (& dark-adapted) eyes in a dark area away from city lights, can see both stars, with Alcor the dimmer one snuggled up to brighter Mizar. Can you spot it? A telescope reveals that Mizar is itself a close double, & spec-troscopy reveals that the 3 stars are actually 6.

¡¡FLASH!! There may be a naked eye comet this month -- COMET 73P/SCHASSMANN-WACHMANN 3 [ * ?? ]be-tween Aquila the Eagle & Ophiuchus the Serpent-Bearer may be bright enough to see with no aids, but one will have to try when the Moon is out of the way. Also use a telescope; the comet has already split into 4 pieces & may fl are up or split again. TIERRA DEL SOL LAT = 32º 36’ 48” N ( ± 0.l” ), LONG = 116º 19’ 55” W ( ± 0.1” ), ELEV = 3710’ ( ± 5’ ), at the bathroom, as determined from USGS 7.5 min 1/24000 map. (See my essay on GPS at www.sdaa.org.)

Send comments & questions to me by phone (619/225-9639), USPS (4538 Long Branch Av., San Diego, CA 92107) or my e-mail address ([email protected]).



SDRP REPORT: The road is horrible and passable by 4X4 capable vehicles only, and the Indians residing on the ad-jacent property have blocked access to the property by welding the gate shut. These developments will be reported to the SDRP.

GOVERNING DOCUMENTS: No report.

NEWSLETTER REPORT: No report.

WEB SITE REPORT: No report.

FORUMS REPORT: No report.

ROBOSCOPE REPORT: No report.

2. New Business• Jim Traweek met with some of our neighbors and they seem willing to work with us.• The neighbor directly to the South of us at TDS would like us to install SDAA signs on her property directing traffi c

to the North (wayward astronomers have driven up her driveway in search of the site) – Mark Lane will make the signs.

• Grant writing – Brian McFarland attended a Grants Workshop held by the Offi ce of Congresswoman Susan Davis. The SDAA Board will meet at a to-be-determined time and place to discuss how to make use of the various sources described at the workshop.


a piece of bubble wrap ready. You can pick out a distant street light and have the guest look through the bubble wrap while explaining that this is what the atmosphere does to the stars and planets. You can even practice holding your hands about a foot apart (as if you are holding a beach ball) to give the ap-propriate scale for our atmosphere. The Night Sky Network is a program sponsored by NASA to provide participating astronomy clubs with material use-ful for explaining astronomical concepts and science. NASA funds the program based on the number of people it reaches and the SDAA gets credit, and occasional goodies, when we use the material. If you fi nd this material useful and use any of it at a star party, lecture, presentation, etc., please let me know and I’ll send the information on to NASA. Thank you to Scott Baker and Rich Strobel for enrolling us in this program.

JUNE 3 - SPRING TDS CLEANUP AND BARBEQUE

Mark your calendar now! On Saturday June 3rd we’ll be do-ing the Spring cleanup at TDS, complete with dumpster so we can fi nish removing the brush pile. Private pad owners - this is your chance to remove those piles of dead brush that are a fi re hazard on your pad. We’ll also be doing general cleanup, so all help is welcome. Come out to the site any time after 9am, and

Continued from Page 4 we’ll be glad to fi nd something for you to do! Special offer to private pad owners -- do you have a cactus or yucca that you want removed? Contact Alice Harvey prior to the 3rd. Plants will be removed and transplanted against the south fence for increased site security (no one wants to jump the fence and land on a cactus!). We will also be having a barbeque in the afternoon, and plan to invite all our area neighbors so they can see what we do out there. Burgers and dogs will be provided, as well as sodas, water, and condiments. Bring a side dish or dessert to share! Contact Alice Harvey ([email protected]) with any questions. See you on the 3rd!

Treasurer’s Report With the addition of our new members we now have a total of 490 SDAA members. We added several new members last month: please welcome Terry Arnold, Erin Ashley, Nicolas Butchko, Michael Hernandez, Kevin Horn, Luis Moreno, and Marviyn Sweeney. Welcome to the SDAA and may you enjoy clear, dark skies! A reminder to our members renewing magazine subscrip-tions: please make payment to San Diego Astronomy Associa-tion not to the publisher. Our members receive group rates if the renewal is processed and paid by the SDAA. Additionally,

Continued on Page 10



there is no need to send a check for membership renewal and a second check for the magazine renewal. One check will do (and cuts down on the paperwork a bit). Also, please do not include any special offers that you may receive from Sky and Telescope or Astronomy. Our system is not setup to handle the special offers that come up from time to time (such as the latest Beautiful Universe 2006 offer from S&T). The only publications that the association handles for you at this time are Sky and Telescope, Astronomy, SkyWatch and Odyssey magazines. Do you have questions about SDAA membership? Has your address changed? Please contact me at [email protected]. If you are an “Electronic” Member, please make sure you forward any changes in your e-mail address to me so I can keep the club database up to date. Please do not contact the SDAA Webmas-ter with membership or magazine subscription questions since he does not have access to this data and refers all inquiries to me. Thank you. Thanks to two very generous donations from Ireland Pre-sentations, Inc. and the City of Poway, the Second Site Fund balance is now standing at $11,160.43!

Who Wants to be a Daredevil?By Patrick L. Barry and Dr. Tony Phillips

When exploring space, NASA naturally wants to use all the newest and coolest technologies—artifi cial intelligence, solar sails, onboard supercomputers, exotic materials. But “new” also means unproven and risky, and that could be a problem. Remember HAL in the movie “2001: A Space Odyssey”? The rebellious computer clearly needed some pre-fl ight testing. Testing advanced technologies in space is the mission of the New Millennium Program (NMP), created by NASA’s Science Mission Directorate in 1995 and run by JPL. Like the daredevil test pilots of the 1950s who would fl y the latest jet technology, NMP fl ies new technologies in space to see if they’re ready for prime time. That way, future missions can use the technologies with much less risk. Example: In 1999, the program’s Deep Space 1 probe tested a system called “AutoNav,” short for Autonomous Naviga-tion. AutoNav used artifi cial intelligence to steer the spacecraft without human intervention. It worked so well that elements of AutoNav were installed on a real mission, Deep Impact, which famously blasted a crater in Comet Tempel 1 on July 4, 2005. Without AutoNav, the projectile would have completely missed the comet. Some NMP technologies “allow us to do things that we liter-

ally could not do before,” says Jack Stocky, Chief Technologist for NMP. Dozens of innovative technologies tested by NMP will lead to satellites and space probes that are smaller, lighter, more capable and even cheaper than those of today. Another example: An NMP test mission called Space Technology 9, which is still in the planning phase, may test-fl y a solar sail. Solar sails use the slight pressure of sunlight itself, instead of heavy fuels, to propel a spacecraft. Two proposed NASA missions would be possible only with dependable solar sails—L1 Diamond and Solar Polar Imager—both of which would use solar sails to fl y spacecraft that would study the Sun. “The technologies that we validate have future missions that need them,” Stocky says. “We try to target [missions] that are about 15 to 20 years out.” A menagerie of other cool NMP technologies include ion thrusters, hyperspectral imagers, and miniaturized electronics for spacecraft navigation and control. NMP focuses on tech-nologies that have been proven in the laboratory but must be tested in the extreme cold, vacuum, and high radiation environ-ment of space, which can’t be fully recreated in the lab. New NMP missions fl y every year and one-half to two years, taking tomorrow’s space technology for a daredevil test drive. This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.


Artist’s rendering of a four-quadrant solar sail propulsion system, with payload. NASA is designing and developing such concepts, a sub-scale model of which may be tested on a future NMP mission.



AISIG Gallery

This month we feature a spread of astrophotographs taken by our Carey Johnson. Carey began imaging Comets, Hale-Bopp was his fi rst, and that is still his favorite target. When there isn’t a comet available, he passes the time imaging Nebulae and Galaxies. His dream? Discover his own comet, although he admits that LINEAR has made this more diffi cult. His computer desktop at work is an image he shot of M42. He uses that image at Stars in the Park, along with planetarium software to show the positions of the moons of Saturn and Jupiter, to help explain why the camera can show more than the human eye. Visit Carey on the Private Pads (and stop in to see his neighbors Kin, Alice, and Mark).

The newsletter has a periodic need for astronomy related photographs. If you have pictures on AISIG that you wouldn’t mind seeing in the newsletter, of if you have pictures sitting on your hard disk that you have been trying to fi nd a good use for, let me know. I would far rather use member pictures in the newsletter than NASA stock photographs.

For Sale:

Celestron Ultima 2000 Computer Automated Telesceope, wedge, tripod, Olympus OM1 35mm camera, Volume 1 and 2 of The Night Sky Observers Guide (Autumn and Winter; Summer and Spring), Solar Filter. All Instructions. Never Used (Disabled Vietnam Vet). $595. 858-503-0032

THE BACK PAGEClassifi eds

San Diego Astronomy AssociationP.O. Box 23215San Diego, CA 92193-3215(619) 645-8940VOL XLII Issue 5, May 2006

Published Monthly by the San Diego Astronomy AssociationSubscription $8.00/year, Single Issue 75¢

NON-PROFIT ORG.U.S. POSTAGE

PAIDPERMIT NO. 3489SAN DIEGO, CA.

MEMBERSHIP INFORMATIONSend dues and renewals to P.O. Box 23215, San Diego, CA 92193. Include any renewal cards from Sky & Telescope, Astronomy, or Odyssey magazine in which you wish to continue your subscription. The expiration date shown on your newsletter mailing label is the only notice that your membership in SDAA will expire. Dues are $50 for Contributing Memberships; $30 for Basic Membership; $50.00 for Private Pads; $5 for each Family membership. In addition to the club dues the annual rates for magazines available at the club discount are: Sky & Telescope $32.95, Astronomy $34, Sky Watch $6.99, and Odyssey $25.46. Make checks payable to S.D. Astronomy Assn. PLEASE DO NOT send renewals directly to Sky Publishing. They return them to us for processing.

Documents

San Diego Astronomy Associationdocs.sdaa.org/Newsletters/2006-05.pdfally,” Alice admits. “But, I made sure I knew something about what I was showing (M42). I spent the entire two