National Capital Astronomers, Inc. Phone: 301/565-3709

Volume 56, Number 4 ISSN 0898-7548 in the Laboratory: Presolar Grains in Meteorites

The next meeting of the National Capi- formed in the winds of ancient stars on information about stellar and galactic tal Astronomers will be held on Satur- in supernova explosions and became evolution, stellar nucleosynthesis of the day, December 6 at 7:30 P.M., in the part of the cloud from which the and elements and processes in interstellar Lippsett Auditorium on the main floor planets formed. The chemical and iso- space and the early Solar System. of the Clinical Center (Building 10) at topic compositions of these grains re- Larry Nittler received a B.A. in the National Institutes of Health (NIH). flect those of their stellar sources. They physics from Cornell University in 1991 Larry R. Ninler of the Carnegie Institu- thus serve as probes of the physical and a Ph.D., also in physics at Washing- tion of Washington, Department ofTer- conditions inside stars and in supernova ton University in 81. Louis in 1996. resiriaJ MagnetIsm win speak on "Stars ejecta. Presola, grains identitied so far Since then, he continued his studies of in the Laboratory: Presolar Grains in include SiC, diamond, graphite, silicon pre solar grains in meteorites via a

Meteorites." The speaker sent the fol- , nitride, A1203 and MgAIP4' This talk postdoctoral fellowship at the Carnegie lowing abstract and biography: will discuss how these grains are iso- Institution. Injest, Larry Nittler refers to Primitive meteorites contain grains lated from meteorites and analyzed in himself as "Interstellar Dust Buster and of "stardust." These tiny specks of dust the laboratory, and how they provide Mushroom Chief." 0

STScI-PRC95-20BA PIECE OF THE ASTEROID VESTA This meteorite is a sample of the crust of the asteroid Vesta, which is only the third solar system object beyond Earth where scientists have a laboratory sample (the other extraterrestrial samples are from Mars and the Moon). The meteorite is unique because it is made almost entirely of the mineral pyroxene, common in lava flows. The meteorite's mineral grain structure also indicates it was once molten, and its oxygen isotopes are unlike oxygen isotopesfoundfor all other rocks of the Earth and Moon. The meteorite's chemical identity points to the asteroid Vesta because it has the same unique spectral signature of the mineral pyroxene. 111e meteorite also has the same pyroxene signature as other small asteroids, recently discovered near Vesta. that are considered "chips" blasted off Vesta 's surface. This debris extends all the way to an "escape hatch" region in the asteroid belt called the Kirkwood gap. This region is swept free of asteroids because Jupiter's gravitational pull removes material from the main belt and hurls it onto a new orbit that crosses Earth's path around the Sun. The meteorite probably followed this route to Earth. It was tom off Vesta's surface as part of a larger fragment. Subsequent collisions broke apart the parent fragment and threw pieces toward the Kirkwood gap and CllfendiJr of fMontnlj (Er;ents

Mondays, December 1, 8, 15,22, and 29, 7:30 PM- Fridays, December 5,12,19, and 26, 7:30 PM-Tele- Public nights at U.S. Naval Observatory (USNO), in scope making classes at American University, Northwest Washington, D.C. (off Massachusetts Av- McKinley Hall Basement. Information: Jerry Schnall, enue). Includes orientation on USNO's mission, 202/362-8872. viewing of operating atomic clocks, and glimpses through the finest optical telescopes in the Washing- Fridays, December 5, 19, and 26, 8:30 PM-Open nights with NCA's Celestron-14 telescope at ton-Baltimore region. Held regardless of cloud cover. Ridgeview Observatory; near Alexandria, Virginia; . Information: USNO Public Affairs Office, 202/762- 1438. Home page: http://www.usno.navy.mil. 6007 Ridgeview Drive (off Franconia Road between Telegraph Road and Rose Hill Drive). Information: Bob Tuesdays, December 2,9, 16,23, and 30, 7:30 PM- Bolster, 703/960-9126. Call before 6:00 PM. Telescope making classes at Chevy Chase Commu- During questionable weather, call the IOTA Hotline nity Center, Connecticut Avenue and McKinley (Phone: 3011474-4945) for NCA meeting status. The Street, NW. Information: Jerry Schnall, 202/362- 8872. absence of a cancellation notice on the Hotline means the meeting will take place. Saturday, December 6, 5:30 PM-Dinner with the See page 8 for more Washington area astronomical speaker and other NCA members at the North China events. Other events too numerous to list in Dust are Rest~urant 0.ll Old Georgetowm Pike. Bethesda, MD. listed in the publications Sky &: Telescope, the Astro- See map and directions on back page. nomical Calendar 1997, the Observer's Handbook Saturday, December 6, 7:30 PM-NCA meeting, will 1997, in numerous software packages, and other links feature Larry R. Nittler, Department of Terrestrial available on the NCA Home Page (see above for ad- Magnetism, Carnegie Institution, speaking on "Stars dress). NCA members can purchase all these (and much in the Laboratory: Presolar Grains in Meteorites." For more) at a discount. To join NCA, use membership directions, see map and directions on back page. application on page 9.

Volunteers Needed For The Astroscout Program TheNational Park Service is looking for Volunteers with telescopes are Bishop Claggett Center in volunteerswhoare willing to assist with needed from 5:45 PM to 7: 15 PM on Buckeystown. Maryland. needs volun- an astronomy program called Saturday, December 13 1997 to bring teers to lead astronomy workshops for "Astroscout." The National Park Ser- their telescopes to Military Field at the middle school students and their fami- vice at the Rock Creek Park Nature comer of Military and Glover Roads for lies on December 29-31. If you can Center and Planetarium is offering to the scouts to view the stars and other volunteer on anyone of these days, Boy Scouts a free, exciting new pro- interesting phenomena. please contact Donna Kerner, Director. gram to learn about astronomy. A mul- The Rock Creek Nature Center and Youth Programs via e-mail at timedia introduction to the night sky, Planetarium is located in Rock Creek [email protected]. this program consists of a planetarium Park at 5200 Glover Road NW. Wash- show, a video, instruction in astronomy, ington DC 20015. If you have any and a viewing of the night sky through questions or would like to volunteer, telescopes. Interested Boy Scouts will please call Ranger Blaine Eckberg at be able to start the Astronomy Merit (202) 426-6829. 0 Badge at this event. The Next Generation Space Telescope by Wayne H. Warren Jr.

At the October 4, 1997 monthly meet- continuum. The COBE map of the dwarfs (as will the Sun) or explode as ing, NCA members and guests were gravitational field shows an anisotropy supernovae to become burned out neu- pleased to hear a lecture entitled "Seeing of about I part in 105. Weare uncertain tron stars or black holes. The material the First Objects with the Next Genera- about how critical this anisotropy is and ejected during these phenomena even- tion Space Telescope" given by Dr. whether or not the Universe would have tually condenses to form the next gen- John C. Mather of the Laboratory for evolved in the same way if completely eration of stars, enriched with heavy Astronomy and Solar Physics, NASA isotropic or if anisotropic to a differing elements synthesized during the explo- Goddard Space Flight Center. Dr. degree. There is evidence that the sive stages of the previous generation. Mather is well-known to longtime NCA clumpiness caused matter to eventually This same material condenses to form members, having given us a lecture combine to form . planets, asteroids, comets, etc., which about the COsmic Background Ex- The Universe continued to expand plorer (COB E) on December 4, 1982. for perhaps 100 Ma before the first gal- Shorter-term members may be familiar axies began to form. The period that with his COBE work as well through the followed, between the formation of the Astronomical Calendars many articles and scientific papers that first galaxies and essentially what we he has published on the subject. Having see today when we look back with HST for 1998 been outstandingly successful with the to about 40 percent to the edge, is what I am again volunteering to place a bulk COBE project, Dr. Mather has been we call the dark age, about which we order for Guy Ottewell' s Astronomical entrusted with the initial responsibilities know practically nothing. We do not Calendar, but the procedure will be for NASA's most "visible" project to fly know why galaxies formed, when or slightly different this because it in the first decade of the new millen- how they formed, or very much about took 3-4 months before I was able to nium. how they evolved. We don't really deliver the orders last year and a few Dr. Mather began by reminding us know what triggered first generation people even had to make special trips to that there are many things that astrono- star formation, although we have lots of my house, as I did theirs. The discount mers (and many other people as well) evidence and some understanding of the is substantial for orders of four or more, would like to know about the Universe star formation process. We believe that viz.therel!u1ar• _. "riceL. _ is- $19.95- + $3.". and still don't. Over the last decade or between 90 and 99 percent of all matter (S&H) = $22.95 each, while the dis- so, we have made tremendous progress in the Universe is invisible to us (the so- count price is $15.96 + $4. (total). To in our quest for astronomical and astro- called "dark matter"), as determined keep things simple, I will collect $17.00 physical knowledge. Sophisticated from the rotation curves of galaxies by for each copy at the December NCA ground-based telescopes and by space the pioneering work of NCA member meeting, so please bring payment with missions such as NASA's COBE, Vera Rubin. We have pretty good ideas you. If we have fewer than four orders, Hubble Space Telescope (HST), about the life cycles of stars, at least that there will be no discount and I will Compton Gamma-Ray Observatory they form primarily in spiral arms of withdraw from service, in which case (CGRO), International Ultraviolet Ex- galaxies, they evolve through different we can order individually. If we have plorer (IUE), and Rossi X-Ray Timing regions of the Hertzsprung-Russell (H- considerably more than four orders, I Explorer (RXTE), plus ESA's HIgh R) diagram according to their changing will refund according to the final cost. Precision PARallax Observing Satellite physical conditions, until they run out of (HIPPARCOS), have contributed to our nuclear fuel and contract to white knowledge. But as much as we learn, there are still many things about which VESTA Caption, Continued from page 1 This 1.4 pound (631 gm) specimen we remain rather ignorant, and new comes from the New England knowledge often leads to more ques- onto a collision course toward Earth. Meteoritical Services. It is a complete tions. Thefragment'sjourney ended in 1960 specimen measuring 3.7 inch x 3.1 Our current understanding, al- when itfell in Western Australia. inch x 3.4 inch (9.6 cm x 8.1 cm x 8.7 though there are alternative views, is NASA's Hubble Space Telescope cm) showing the fusion crust, evidence thatthe Universe began (or began again) observations further confirm this of the last stage in its journey to with the so-called "Big Bang" about 13 scenario by revealing a giant impact 9 Earth. Photo Credit: R. Kempton billion ago (also written 13 x 10 basin on the 325-mile (525 km) years or 13 Ga). As the Universe ex- diameter asteroid. The ancient impact (New England Meteoritical Services) panded and cooled, the original opaque was so powerful, it tore off a piece of ~ Don't throw this newsletter plasma became transparent at about age the asteroid's crust, exposing a deeper 3 x 1()5years. As we look outward ~ away. If you're finished with mantle of rock. Most of the identified toward the edge, as we did using the . it, pass it on to someone else to meteorites from Vesta are in the care COBE satellite, we see structure that we read or recycle it. It's right for as- of the Western Australian Museum. interpret as ripples in the space-time tronomy and the environment. eventually be followed by extrasolar the atmosphere. Even though adaptive eventually yield such things as rocks, planetary weather mapping if such a optics techniques are greatly improving minerals, organic chemicals and, in the thing is ever possible, but that would atmospheric "seeing" problems, the case of the Solar System, such things as almost certainly be at least several gen- situation is still far superior in space, we like to think of as intelligent beings erations away. where resolution is limited only by the who can study these phenomena. One Dr. Mather delved more deeply into optical quality of the telescope and dif- thing that we can be sure of is that what the NGST should be able to ac- fraction effects. At longer wavelengths, virtually all of the materials that we complish. As mentioned earlier, NGST atmospheric effects are somewhat re- encounter every day originated in some will study the dark period when galaxies duced on the ground, but emission by supernova explosion that occurred and their constituent stars first formed. hydroxyl radicals, atmospheric water, somewhere in the Milky Way more than It will also attempt to determine the and other constituents, either severely 5 Ga ago. "shape" of the Universe by measuring limits or entirely blocks extraterrestrial We'd really like to know more the curvature of space, which requires radiation. Clearly, a space-borne instru- about the details of this evolutionary the determination of distances to ex- ment is not constrained by all these process, especially about the end pro- tremely remote objects using, for ex- problems, plus it is easy to keep the cesses that result in the highly con- ample, supernovae as standard candles. structure cold by merely shielding it densed objects mentioned above. Do Late stages of will be from direct sunlight. black holes disintegrate? Is interstellar studied, as well as early stages near the Among the important scientific space littered with the burned out cin- bottom of the main sequence, where questions to be studied by the NGST is ders of black dwarfs and neutron stars? low-mass objects sometimes become how galaxies form and evolve. Dr. What fraction of dark matter do these stars and sometimes end up as brown Mather showed the classic tuning fork cinders represent? What about the dwarfs, depending on their masses. diagram that Hubble devised in his at- large-scale structure of the Universe? Closer to home, the NGST will attempt tempt to classify galaxies. This shows What is its actual shape, if such a thing to directly observe objects in the Kuiper the various types of spirals, as classified can even be defined? The Universe is Belt, which is a zone between the orbits by the tightness, numbers of arms, and expanding, but what is it expanding of Uranus and Neptune that is thought to the presence or absence of a "bar" along into? Is space being created at the edge? be the origin of certain classes of com- the major axis. It also shows different We hope to be able to answer at least ets. kinds of ellipticals from the essentially some of these profound questions with Another important objective is to round to the very oblong. We once the next generation of space-borne mis- extend NGST's sensitivity far enough thought that spirals somehow naturally sions that will be flown by NASA, ESA, into the infrared (IR) to detect emission evolved to ellipticals, because the latter and possibly other space agencies from objects at room temperature. This seemed to contain less dust and older around the world. is approximately 300 (K), for stars. Our picture of this process has which the emission peaks at 10000 na- changed dramatically over the last 20 NGST And Other Planned Missions nometers (nm), as compared with stellar years with the realization that galactic Dr. Mather briefly describe some of the temperatures of 3000 K (peaking at 700 merger events are rather common. As oo K discussed by Dr. Fran~ois Schweizer atססplanned NASA missions. The NGST nm) for red (M-type) stars to 3 will be designed to study the dark region (200 nm) for very hot (O-type) blue the February 5, 1994 NCA meeting, mentioned earlier. It will tentatively be stars. The detection of such cool objects merger events not only produce many of launched in 2007. There is a Space is tricky, however, because everything the irregularly shaped and peculiar gal- Interferometry Mission (SIM), sched- in the detecting structure must be kept axy forms, but may also produce ellipti- uled for launch in 2005, primarily de- cold enough so as to not emit IR radia- cal galaxies as their end products. We signed to detect extrasolar planets. The tion itself. Of course, such techniques should be able to learn about the forma- mission's extremely high resolution have been developed for missions such tion of galaxies if we can look back far will afford us the opportunity to mea- as NASA's Infrared Astronomical Sat- enough to see their initial formation. sure the distances of stars on the other ellite (IRAS) and the currently operat- The Hubble deep field image shows side of the to ±IO% accuracy. ing ESA Infrared Space Observatory galaxies having redshifts up to about 5, We might think of thi!; mission as the (ISO), so there shouldn't be major prob- which is not nearly back far enough successor to HIPPARCOS, although the lems in that area. (look-back time 5 Ga) to reach the for- Europeans have another astrometric Dr. Mather explained more about mation era. NGST should be able to see mission on the drawing board for the why we want to build the NGST. First of to a redshift of 10-13, corresponding to 2000-2002 time frame. Farther down all, why do we need a larger telescope in look-back times of 11-12 Ga. The ob- the line, perhaps in the 2012-2020 time space, where the cost is so much higher? servation of objects with such large red- frame, depending on how soon we can As we've seen by comparing images shifts is, of course, a major reason that figure out how to do it, would be a from the HST with what we have tradi- the NGST must be sensitive in the near- mission to take spectra of extrasolar tionally been able to do from the ground IR region where the HST becomes less planets to detect the presence of gaseous using much larger telescopes, there are sensitive. atmospheric constituents such a meth- many problems with observing through Another important topic to be stud-

ane, CO2, water vapor, etc. This might ied by the NGST is the early stages of star formation. HST images of star mittee formed by NASA several years orbit at the same distance, but perhaps forming regions like the ones in Orion ago to study the various options for 60 degrees or so behind the Earth. A show what appears to be gas flow future space astronomy missions. This more ambitious possibility is to place around small opaque objects (globules) committee, consisting mostly of non the NGST farther away from the Sun, inside which stars may be forming. It is NASA scientists, made a three-part rec- perhaps outside the asteroid belt, maybe hoped that the NGST, with its IR sensi- ommendation: (1) Continue to operate even outside the plane of the Solar Sys- tivity, will be able to penetrate many of the HST as an ultraviolet-and visible- tem to escape from most of the inter- these clouds to reveal the protostars in- wavelength facility; (2) develop capa- planetary dust that interferes with obser- side. Images of the Horsehead bilities for space interferometry, which vations, especially in the IR. region in the visible and IR show clearly uses multiple telescopes to construct that the latter do penetrate the cloud to images having resolutions comparable Possible Designs show internal activity. to a single instrument of size equal to the Keeping the telescope cold in space is As these protostars age, they de- separation of the interferometer, and; not a serious problem because it is only velop disks of dust that we think eventu- (3) develop a successor to the HST that necessary to shield it from the Sun with ally condense into planetary bodies. is IR-sensitive and considerably larger a sun shade. We then saw illustrations of HST images shown by Dr. Mather re- in aperture. As a result of recommenda- several telescope and sunshade designs. veal such disks around stars like ~ tion 3, NASA Headquarters invited The most important factor is probably to Pictoris. The amount of material in this GSFC in October of 1995 to propose find a way to make an 8-meter telescope system indicates that protoplanetary how this might be done and subse- objective light enough to launch with a collisions have occurred. (We heard a quently provided some funding to carry low-cost rocket, which is necessary to lot about the ~ Pictoris phenomenon out a feasibility study resulting in spe- keep the mission cost under control. from Dr. Carol Grady at our November cific recommendations. The detector The rather flexible tolerances in the mir- 2, 1994 NCA meeting.) NGST should system should be sensitive in the IR to ror figure make it possible to use novel allow us to see closer to these stars and see through dust and to observe the most techniques to make a thin mirror, and to perhaps reveal additional details distant galaxies. The extremely high University of Arizona mirror expert about the nature of their debris. Dr. optical quality originally specified for Roger Angel has already made a thin Mather showed quite a few HST images the HST is not required in the IR if we mirror of sufficient accuracy. The thin of protostellar disks in Orion and of optimize for observations at 2 microme- glass is supported by a large number of regions of star formation in other nebu- ters (urn), and this results in substantial adjusting screws that are controlled by lae. cost savings. The telescope aperture picomotors, which are devices con- Dr. Mather next turned his attention was initially to be at least 4 meters, as trolled by piezoelectric drivers. The real to the dark matter problem mentioned determined primarily by weight consid- trick is to build such a mirror in pieces earlier. He showed an image of a distant erations and launch capabilities. How- and assemble it in space to reproduce the cluster of galaxies in which gravitation- ever, subsequent calculations showed required figure. It is assumed that thou- ally lensed arcs of more distant galaxies that at least 8 meters would be required sands of adjustments would be neces- can be seen. Since the degree oflensing to do the desired science, so new ways sary, so those capabilities must be built depends on the total mass of the lensing must be developed to place the NGST into the system. Obviously, there are "object", in this case the foreground into orbit. many problems to be worked out, but cluster of galaxies, the total mass can be In addition to the launch problem, with the technology improvements estimated. An estimate of the mass of consideration of where to place the bound to occur over the next decade, the luminous matter can be made by NGST is important. Although the HST along with recent advances in telescope classifying each galaxy in the cluster, is in low Earth orbit, which makes peri- and instrument making, it should be assigning a typical mass for that type of odic visits possible, there are many possible to construct the necessary galaxy, then summing over all galaxies. problems associated with a 90-minute equipment. Although these estimates may be a orbit, such as Earth eclipses, orbit de- Current plans for the instrument bit rough, a comparison of the two generation, the difficulty of making cluster include four detector systems. masses gives one result that leads us to longer observations, etc. For these rea- The central instrument is an infrared believe that the ratio of dark to luminous sons, it is recommended that the NGST camera with a 2 arcminute field of view. matteris roughly 10 to 1. Essentially the be put into a more distant location. One A longer wavelength camera and three- same results are found from the rotation possibility is, of course, a geosynchro- dimensional spectrometer capable of curves of individual galaxies. While nous orbit, but there are several others. taking spectra of hundreds of galaxies rotation curves have only been deter- An excellent possibility is the L2 simultaneously would be located mined for relatively nearby galaxies to Lagrangian point, which is located around the perimeter of the focal plane. date, the NGST should be able to extend about 1.5 million kilometers outward this work to much greater distances. from Earth away from the Sun. This NGSTVs.HST point is actually easier to reach than the Dr. Mather ended his talk by comparing NGST Requirements geosynchronous orbit. Another possi- ideas for the NGST with what was done The decision to build the NGST resulted bility is to launch away from Earth and from recommendations made by a com- let the satellite slowly move into a solar TELESCOPE, Continued/rom page 5 niques needed for the construction of the next century, there should be much ex- for the HST about 25 years earlier. The NGST are not yet fully developed, but citement and gratification for those of us new observatory will be larger but con- we have learned many things along the who crave more understanding of the siderably lighter (about one quarter the way and believe that the project is tech- Universe in which we live. weight). Adjustable optics will be used, nologically feasible. The NCA is indebted to John which should avoid the kind of disaster There is little doubt that, with the Mather for giving this fascinating in- that took place with the HST primary capabilities described for the NGST by sight into what we can expect from mirror. The greater distance from Earth Dr. Mather, we would learn a lot about space astronomy over the next few de- means that longer observations will be some of the most perplexing outstand- cades. I thank John for reviewing this possible with simple techniques, al- ing problems in astronomy and astro- "review" prior to publication. 0 though the observatory will not be ser- physics. Along with the other missions viceable except remotely. All the tech- planned for the first few decades of the

Naked-eye Occultation Saturday Evening, Dec. 6th; Other Northeast U.S. Events

by David Dunham

If it is clear early Saturday evening, the occultation with a carncorder even if pointed into the eyepiece of a telescope; December 6th, bring a camcorder or you don't have a WWV receiver. But predictions for them are given below. binoculars to the NCA meeting. Just we will use CNN Headline News rather The events marked with * can probably before it begins, at 7:29 pm, the 3.7- than The Weather Channel for the TV be recorded directly with a camcorder magnitude red star A. Aquarii will disap- time reference station. If you have nei- without a telescope, if your camcorder is pear behind the dark edge of the first ther WWV nor cable, call the U.S. Naval 12x or higher, but the Aldebaran disap- quarter Moon, which will be 39 degrees Observatory master clock at 900-410- pearance will be hard without a scope above the southwestern horizon. 8463; the call should be placed via since the bright part of the nearly full Weather permitting, we will observe the AT&T to ensure use ofland lines, which Moon will be very close. The events occultation from the parking lot north- will give an accuracy of a couple of marked with? might be recorded di- west of the Building 10 entrance. If hundredths of a second. If the call is not rectly if conditions are good. When conditions are good, the event might made via AT&T, orifthe National Bu- aiming a camcorder into an eyepiece for even be seen without opticaillid. Bm reau of Standards' WWV- 303-area- events relatively farfromthe sunlit part binoculars are recommended for a good code number is used, the call might (or of the Moon, first focus on the sunlit part view. We will have a WWV time signal might not, you would not know) be of the Moon with autofocus, then switch receiver. Recording that and the occul- routed through a geosynchronous satel- to manual focus as you move the view tation with a camcorder can time the lite, causing a quarter-second delay, towards the star. The Hyades disappear- event to 0.03 second, which defines the which is unacceptable. In the Washing- ances that precede Aldebaran's disap- star's position relative to the Moon's ton, DC area, the USNO master clock pearance on Friday evening, Dec. 12, limb to about 30 meters accuracy, better can be reached with a local call to 202/ will be easy just using autofocus since than the Clementine spacecraft lunar 762-1401, but those outside of the DC those events will all occur close to the laser altimeter measurements. These toll-free area should not use that num- terminator, providing a good reference observations are valuable for defining ber, because it might go through a satel- for the autofocus. See IOTA's Web the lunar profile, information needed to lite. Record the time just before and page at http://www.sky.net/-robinson/ properly analyze solar eclipse observa- after the occultation (maybe even dur- iotandx.htm for more information. The tions to determine climatically signifi- ing it with a portable phone). Next predictions on the next page were com- cant variations. Even if you week, a view of the Moon showing puted for Greenbelt, Maryland, about 12 can't come to the meeting, wherever where A. Aquarii will disappear at sev- miles northeast of downtown Washing- you are, it would be valuable if you can eral North American cities will be ton, DC, but the times will usually be take a few moments to step outside and placed on our Web site given at the end good to within a minute within 40 miles tape the occultation with a camcorder. of this notice, but it is not needed to of Greenbelt, with the occultation usu- See pages 94 and 96 of the July issue of observe the event. The star is so bright ally occurring earlier in the western sub- Sky and Telescope for accurately timing that, even with a telescope, a low power urbs. For more accuracy or more distant can be used so that the whole dark side locations, the A and B factors can be Roving and Revolving of the Moon can be viewed, and the star used, as described in the explanation of Over the Red Planet simply followed up to the edge of the the predictions given at the end. Also, Moon to the disappearance. More use- predictions for other locations will be The review for the November meet- ful on the Web site is a list of the pre- supplied upon request bye-mail at ing was not available at press time. dicted Universal Times for about 200 [email protected] for observers who It will be published in the next News- North American cities. will try to time many ofthese events. 0 letter. There are several other occultations that can be taped with a camcorder 1.0.T.A.Total Occultation Predictions For 1997 December for Greenbelt, Maryland, Longitude W 76d 52' 09.9", Latitude +38d 59' 10.1", Height +53 meters

DAY E.S.T. P Z.C. VIS SP PCT SN MN MN CUSP A B Star H M S NO. MAG SNLT AL AL AZ ANG M/O MfO Name 6 19 29 29 D* 3353 3.7 MO 47+ 39 210 59S 122 -2.1 -1.0 A. Aquarii 6 20 45 22 D 3360 6.3 KO 48+ 30 23(l 88S 93 -1.2 -D.3 78 Aquarii 7 20 17 26 D 3505 5.6 KO 59+ 43 212 60N 61 -1.1 + 1.3 20 Piscium 10 17 41 58 D 368 6.3 KO 88+ 34 106 30S 146 -1.8 -D.3 12 19 55 29 D 667 5.3 G5 98+ 42 104 77N 57 -D.7 +2.3 75 Tauri 12 20 04 12 D 672 6.6 F8 99+ 44 106 52S 107 -1.4 +0.8 12 21 00 03 D 677 4.8 A5 99+ 54 119 35S 124 -2.1 -D.2 12 21 15 14 D 680 6.7 F2 99+ 56 124 16S 144 -2.7 -2.0 12 22 59 57 D 685 6.5 FO 99+ 67 172 15S 143 -2.7 -3.0 13 00 16 38 D* 692 0.8 K5 99+ 64 215 37S 120 -2.1 -1.5 Aldebaran 13 01 26 26 R 692 0.8 K5 99+ 54 241 -84S 241 -1.7 +0.8 Aldebaran 19 04 59 46 R 1486 4.6 K2 73- 60 198 43N 317 -1.0 -3.3 31 Leonis 20 06 18 18 R 1589 5.7 M2 64- 53 211 90N 269 -1.9 -1.4 56 Leonis 21 00 26 51 R 1678 5.8 F5 56- 11 95 lIS 190 -D.4 +7.4 89 Leonis 22 00 57 16 R? 1772 3.9 AO 47- 6 96 46S 225 -D.3 +2.3 £ Virginis 24 02 49 32 R 1994 6.5 F8 28- 6 106 41N 320 +0.1 -1.6 26 04 49 32 R* 2223 4.0 KO 12- 7 115 83N 283 -D.4 +0.4 Y Librae

The columns in the IOTA table above are defined as follows: DAY E.S. T. (H M S) gives day of month and hours, minutes, seconds of the predicted Eastern Standard Time of the occultation event. P is phenomenon: D for disappearance, R for reappearance. Z.C. NO. is the star's number in Robertson's Zodiacal Catalog. VIS MAG is the visual magnitude of the star. SP is the spectral type of the star. PCT SNLT is the percent ofthe Moon's disk sunlit (100% = Full Moon), followed by + for waxing, - for waning. SN AL is the altitude of the Sun above tile horizon, given only when it is greater than or equal to -12. All angles are in degrees. MN AL is the altitude ofthe Moon above the horizon. MN AZ is the azimuth of the Moon, measured along the horizon eastward from the north point. CUSP ANG is the cusp angle of the event. This is the angle from the nearest lunar cusp to the star. The nearest cusp is identified by letter as the north (N) or south (S) cusp. Cusp angle is positive on the dark limb and negative on the bright limb. W A is theW atts angle of the event, measured at the center of the Moon's disk from the Moon's north rotation pole eastward to the star. It can be used with a lunar map to estimate the point of reappearance of a star relative to lunar features; a W.A. of 270 is near the lunar equator, 180 is near the south pole, and 360 is near the north pole. Events near WA 290 are conveniently close to Mare Crisium. A B (M/O M/O) are the rates of change of the predicted occultation time with changes in the observer's longitude and latitude, respectively. The units are minutes of time per degree of west longitude or north latitude (M/O).

Dec2 Tue 17:12 ZC2773 6.0 8+ -IS Myersville, MD (S-5) & Logansvil.,PA, -6 Dec5 Fri 18:17 ZC 3211 8.0 35+ 4S Olney, Clarksv., & BelAir, MD (Sun-17dg)

dmag duro s Dec I Mon 19:41 PPM 183823 9.4 Neoptolemus 7.9 8 Virginia Dec 3 Wed 17:58 SAO 189113 9.0 Herculina 2.8 6 e. Carolinas Dec4 Thu 7:06 SAO 134036 6.0 Artemis 7.1 II Wisconsin Decl4 Sun 5:03 PPM 195501 9.5 Hilda 4.8 7 Mexico Dec27 Sat 1:45 44 Eridani 5.5 Nipponia 7.5 4 Georgia

Phone the IOTA occultation line, 301-474-4945, for updates and details; also, meeting places and maps for grazing occultations are often given on IOTA's Web site at http://www.sky.net/-robinson/iotandx.htm National Capital Area Astronomical Events Cosmos Revisited December Free Lectures at the Einstein Planetarium and Other Daily Events National Air & Space Museum Life as a Planetary 202/357-1550,202/357-1686, or 202/357-1505 (TTY) Phenomenon Home page: http://www.nasm.edu By Andrew Knoll

Lectures begin at 6:00 PM at the Na- tional Air and Space Museum. For more Other Planetariums, shaped asteroids and planets trans- information, call Missy Snelling at 202/ 357-4260. Observatories, and Science forming them from rocks to worlds. December 5, 12Noon. Baird Audi- Centers in the Area torium, Free to the public. National Air and Space Museum Montgomery College Plan- "A Global -"Together in Space", speaker: etarium -"Day of the Sun's Re- Perspective on turn, the Winter Solstice" Takoma Rob Landis from Goddard Space Galactic Evolution" Park, MD. December 20. (See their Flight Center will present a histori- By Michael Fall web site at http://myhouse.comlmc/ cal overview of the Soviet space (STSI) planet.htm.) progam and preview the programs being planned as joint ventures be- "Implications of Campus Observatory Open tween the U.S. and Russia. Decem- Meteoritic Presolar House - "Magnetic Storms on the ber 27, 6:00 PM, Einstein Plan- Grains for Galactic Earth and Other Planets", speaker: etarium. Evolution" Dennis Papadopoulos. Department by Conel Alexander of Astronomy, University of Mary- Mount Rainier Nature & Recre- (DTMlCIW) land, College Park, MD. December ation Center - "Winter Stars" 5, 8:00PM. Historic Bladensburg Waterfront Seminars are held on Wednesdays at Visitors Center, 460 I.AnnapolisRd, 11;OOa,m. in·theSemiftaf;,~ "Topic to be announced.", speaker: Bladensburg, MD. Due to construc- Main (old) Building. Coffee and tea Dr. Pat Harrington. Department of tion, activities at the Waterfront will be served at 10:45 a.m. Please call to confirm that there have been no can- Astronomy, University of Mary- Center may be moved to an alternate land, College Park, MD. December cellations. DTM is located on 32nd site. Call Jean Tierney at 301/627- Street, one block south of its intersec- 20, 8:00PM. 6074 for information. December 5, tion with Military Road. Proceed south 6:30-8:00 PM. National Museum of Natural His- on 32nd Street, one block to Jocelyn Street, turn left on Jocelyn and right into tory -"After the Planets Formed", Check your local web sites for any speaker: Mereoriticist Dr. Timothy the parking lot. CIW, 2021686-4370 other events that may be happening (Extension 4378 or 4383) McCoy describes the process that in the area.

www. maa. mh n. de/Comet! who is in the process of placing his book calendar.html. Also referenced is Gary on line. He also keeps a calendar and Meteor Showers for December W. Kronk, author of the book Meteor wrote a historical piece on "Meteors Showers: A Descriptive Catalog (1988) and the Native Americans." Puppids-Velids Nov 27-January (Max: Dec. 9 & Dec. 26) Newsletter Deadline for January Star Dust, December 15, 1997 Dec 7-16 Send Submissions to Alisa & Gary Joaquin, at 4910 Schuyler Dr, Annandale, (Max: Dec 13) VA,22oo3-5144. Leave a message on voice mail703nSD-1636. Text files or graphic files in .GIF or .TIFF may be sent via E-Mail to [email protected] or fax Dec 17-25 submissions to 703/658-2233. No submissions will be accepted after the (Max: Dec 23) 20th. There will be no exceptions. We need a reasonable amount of time to design, edit, and review this newsletter. The Holidays are upon us and we would Meteor web sites to explore: appreciate everyone's help in this matter by getting everything in on time. We www.ticetboo.demon.co.uk/ will be going to Nebraska and we will need to get this mailed before December meteors.htm which includes a link to a 23. Thank you. site on anomalous meteor phenomena, National Capital Astronomers, Inc.

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