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National Capital Astronomers, Inc. Phone: 301/320-3621
Volume 54, Number 6 February, 1996 ISSN 0898-7548
Robotic Telescopes on the Moonby Harold Williams
The next meeting of the National Capi-tal Astronomers will be held Saturday,February 3, at 7:30 P.M. in the LipsettAuditorium of the Clinical Center(Building 10) at the National Institutesof Health (NIH). Peter Chen, who isemployed by the Computer ScienceCorporation (CSC) in the Laboratoryfor Astronomy and Solar Physics at theGoddard Space Flight Center (GSFC),and combines astronomical researchwith instrument design, will speak about"Robotic Telescopes on the Moon." Hegot his Ph.D. from the University ofTexas at Austin, where he started doing
occultation timings; Peter recommendsthis as an exciting and fun thing to dowith small portable telescopes used in atime-critical way. As one of manyspeakers on our Charge Coupled De-vices (CCD's) program, he spoke to usin September on Charge Injection De-vices (CIDs) and demonstrated aCIDcamera in operation .' He mentioned theprojected use of CID chips as imagedetectors for Lunar telescopes in thatmeeting, and it was decided to ask himto speak about robotic telescopes on theMoon in greater detail at a future meet-ing. That future is now.
NCA and Astronomy on the World Wide WebReviewed by Harold Williams
On Saturday January 6, 1995 at the Na-tional Institutes of Health (NIH) in theLipsett Amphitheater, the World WideWeb (WWW) and NCA web page weredemonstrated by various NCA mem-bers. Tom Van Flandern, Jay Miller,Wayne Warren, Nancy Roman, and Iwere the most conspicuous demonstra-tors; Michael Marie and LescellesLinton also contributed URLs worthvisiting, and Lescelles had assisted meall of Saturday in improvements onNCA's home page at http://myhouse.comINCAlhome.htm.
HTML, HyperText Markup Lan-guage, is just a DTD, Document TypeDefinition, written using SGML, Stan-dard Generalized Markup Language,invented by Tim Berners-Lee while at
CERN, Cente Europeen de RecherchesNuclearies, before he moved to directthe W3 Consortium. It is obvious thatfor this subject it is easy to constructsentences that are so full of acronymsand abbreviations as to be unintelligibleby everyone except the most dedicatedWWW adapt. With the rich use ofacronyms in this meeting one of ourmembers came up with yet another ab-breviation for STARS, (Stop TalkingAcronyms Reduce Street-lighting.)
People who have recently discov-ered the WWW act like people did whenthe telephone or television was new.They get excited and want to share thisnew resource with their friends andneighbors. After a short period of over-indulgence in the new media-people
with addictive personalities spend alittle longer in this phase-they settleinto a responsible use of the now com-mon utility. Perhaps this sort of behav-ior even happened after Gutenberg in-vented the printing press, but at that timethe majority of the citizenry in Europecould not read.
The program consisted of jumpingfrom site to site on the WWW withpeople firing questions at the person orpersons doing the demonstrating. If thepresentation was chaotic at times, itschaos reflected the chaos inherent in theWWW. I have decided that the onlything worth reviewing in detail are theabbreviations, acronyms, and terms, sohere it goes.
See www, continues on Page 3
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Saturday, March 2, 1996, 7:30 PM-The MarchNCA meeting will feature Eli Dwek speaking on"Searching for the Cosmic Infrared Background."
Wednesday, March 6, 1996-March "Sky Watch"column appears in The Washington Post "Style" sec-tion. It lists many events for that month.
Page 2
Calendar of Monthly Events
The Public is Welcome!
The Calendar's Saturday "Deep Night" Periods-Astronomy is quite unique among the sciences in thatthe original specimen of study, the Universe itself, isaccessible to each of us possessing the gift of sight. Weneed only look up at the sky with wonder. And thereis no better place to experience that original specimenthan at a dark-sky site during "deep night" periods.For many, Saturday nights represent the most conve-nient times to do that.
The Saturday deep night periods listed in this issue's"Calendar of Monthly Events" occur on two to threeSaturday nights each month. They are continuous timeintervals, of three or more hours duration, that start onSaturday night before Midnight EST, when neitherdaylight, twilight, nor Moonlight interferes with expe-riencing the dark sky. However, artificial light, in theform of light pollution, can interfere. To avoid thisproblem, several relatively dark-sky sites are availablefor NCA members' use in Maryland, Virginia, andWest Virginia. Information: Daniel Costanzo, 703/841-4765.
This deep night listing was prepared by DanielCostanzo from data generated by Jay Miller usingMICA, the Multiyear Interactive Computer Almanacsoftware package, created by the U.S. Naval Observa-tory. MICA is publicly available in both PC andMacintosh versions. Several NCA members can assistthose interested in learning to use MICA.
Other events too numerous to mention here are listedin the publications Sky & Telescope, the AstronomicalCalendar 1996, and Observer's Handbook 1996, andin numerous software packages. NCA members canpurchase all these at a discount. To join NCA, usemembership application on page 9.
Fridays, February 2, 9,16, and 23, 7:00-9:30 PM-Mirror-making classes with Jerry Schnall in the base-ment of McKinley Hall at American University offNebraska Avenue, NW in Washington. Information:202/362-8872. See article on page 4.
Saturday, February 3, 5:30 PM-Dinner with ourspeaker will take place at North China Restaurant,7814 Old Georgetown Road (near Cordell Avenue),Bethesda, MD., before the monthly meeting. We willstart ordering at 5:30 PM. See the map on the backpage of this issue for directions.
Saturday, February 3,1996,7:30 PM-The Febru-ary NCA meeting will feature Peter Chen speaking on"Robotic Telescopes on the Moon."
Mondays, February 5, 12, and 26, 8:30 PM-Publicnights at the U.S. Naval Observatory (USNO), inNorthwest Washington, D.C. (off Massachusetts Av-enue). Includes orientation on USNO's mission,viewing of operating atomic clocks, and glimpsesthrough the finest optical telescopes in the NationalCapital region. Information: USNO Public AffairsOffice, 202/653-1541.
Tuesdays, February 6, 13, 20, and 27, 7:00-9:30PM-Mirror-making classes with Jerry Schnall at theChevy Chase Community Center at Connecticut Av-enue and McKinley Street, NW in Washington. Infor-mation: 202/362-8872.
Wednesday, February 7-February "Sky Watch"column appears in The Washington Post "Style" sec-tion. It lists many events for that month.
Fridays, February 9, 16, and 23, 8:30 PM-NCA'sCelestron-14 telescope open nights with Bob Bolster,6007 Ridgeview Drive, south of Alexandria offFranconia Road between Telegraph Road and RoseHill Drive. Call Bob at 703/960-9126.
Saturday, February 10, Night-Waning GibbousMoon provides this month's third longest night "deepnight" period, including mostly Moonless skies fromdusk through Midnight EST, (The second longest suchSaturday night period, 24/25 February, only beginsafter Midnight EST.) See explanation below.
Saturday, February 17, Night-Waning CrescentMoon provides this month's longest Saturday night"deep night" period, with Moonless skies all nightlong. See explanation below.
WWW, from page 1
A browser is a program on yourcomputer that allows you to surf theWWW. Surf is used here as a metaphor.There are only four browsers worthmentioning: Lynx, a text based browserthat will run on a shell account;Netscape, the best graphic and text-based browser on the market; Mosaic,the original graphic and text-basedbrowser created by some of theNetscape people when they were stu-dents at the University of Illinois andconnected with the NCSA, NationalCenter for Supercomputer Applica-tions; and all the rest of the graphicbrowsers, which are mostly lame or justa little lame when compared toNetscape.
A shell account is what you havewhen you log on to an Internet service ifall you ever get is a prompt of some sortwith a command line interpreter, CLI, orshell. You can run Lynx from a shellaccount by typing lynx and the URL atthe prompt. SLIP stands for Serial LineInternet Protocol, an unofficial butwidely used method of running TCP/IPover serial lines such as dial-up phonelines. TCP/IP, strictly speaking, isTransmission Control Protocol, whichruns on top of the Internet Protocol, butby metaphoric extension TCPIIP gener-ally refers to a suite of network andapplication protocols including TCP,IP, UDP, ICMP, Telnet, FIP, and oth-ers. You don't need to know what UDPand ICMP are unless you are a networkadministrator-I haven't a clue andcouldn't care less at the moment.
Telnetis the standard TCPIIP appli-cation for remote login, and it allowsyou to emulate some sort of terminal.That must be what the T is for. Gener-ally after you tel net you are asked forlogonid and password.
Rlogin is another standard TCPIIPapplication for remote login; as far as Ican figure out it does not allow you toemulate a terminal. You generally haveto rlogin instead of telneting if you wantto run TIA or Sliper to make your shellaccount behave like a SLIP or PPP ac-count. Generally after you rlogin youare asked for logonid and password.PPP stands for Point-to-Point Protocol,a standard for networking connectionson serial hardware; it is most often usedwith TCPIIP but can support other pro-
tocols simultaneously-whatever theyare. PPP is generally agreed to besupe-rior to SLIP by those that know. ATM(Asynchronous Transfer Mode) issomething superior to SLIP and PPP; allthe hardware makers are bragging aboutit, but it isn't here yet. TIA or Sliper aretwo different products that reside on anInternet host provider that allow those ofus that are either too cheap or are notproperly network connected to rungraphic browsers that normally requireSLIP or PPP connections. TIA standsfor The Internet Adapter and is sold bymarketplace. com for $30, but you get athree-week free trial. Sliper is free, butyou probably get what you pay for.
FIP is File Transfer Protocol, anapplication that does what it name says.You can use FIP to logon to anothersystem and get and put files. Of course,file security could prevent you fromgetting or putting on a specific site. FIPhas a few simple commands, and it canbe invoked from the shell. Enter FIPand then press? or h to list the availablecommands. Help or ? and the name ofthe command will tell you more.Netscape will allow you to FIP as well.FIP is typically where and how you goto get lots of free and shareware pro-grams and data. You can get Netscapethat way, too.
URL stands for Universal ResourceLocator, a WWW address that you typeinto your browser or click on the high-lighted tag (sometimes called an anchor,a curious name for something that takesyou elsewhere). http://myhouse.com/NCAlhome.htm is the URL for NCA'sWWW page. URLs are broken downinto five and occasionally six parts,which are scheme://host.domain[:port]/path/filename. Schemes can be http, afile on the WWW server; file, a file onyour local system (for example, c:would generally be on your hard driveon an IBM compatible system, a: or b:would be a diskette on your system);FIP, an FIP server in this context;news, a Usenet newsgroup (there aremore than 10,000 of these and severalastronomy ones are available from theNCA home page); gopher, a gopherserver (a more primitive text-basedmenu-driven information server thanthe WWW); W AIS, a Wide Area Infor-mation Server database search engine (Ihave heard of them but never used one.);and telnet. Host.domain is a specific
computer on the Internet, such asmarlowe.umd.edu or myhouse.com orwww.altvista.digital.com or even an IPaddress such as 198.69.192.1. Actuallythe word names in the host.domain haveto be translated to IP numbers by adomain name server into IP addresseslike 198.69.192.1, but you generallydon't have to be too aware of all of thisunless you are configuring TIA duringsetup or you are a network administra-tor. As for what is the host and what isthe domain, that is somewhat a judge-ment call. umd.edu is a domain forUniversity of Maryland computers; ob-viously digital. com is a domain namefor Digital, the big computer company;but myhouse.com is in some ways thedomain and myhouse the host.Marlowe, Tracy, Wolfe, and Marple arehost individual machines at umd.edu ina UNIX cluster. Now when it comes todomains, knowing a little will some-times help you a lot: edu is an educa-tional institution, com is company, govis the government, mil is the US mili-tary, org is an organization; but twoletters on the end are country codes: deis Germany, fi is Finland, ca is Canada,uk is the United Kingdom, jp is Japan,and au is Australia. [:port] is a number;and you generally don't need one unlessthe network administrator at thehost.domain is stupid or has been fouledup by some higher administrator that isstupid. Path is the path through thehost.domain's directory file structure toget you to the file. So what is http://boas3. bo .astro .it/dip/Museum/MuseumTurret.html#astrolabe, yousay? http is the scheme, so it must be anhtml document. boas3.bo.astro.it is thehost.domain, a unique computer on theInternet, evidently in Italy. dip/Mu-seum/ is the path to a file calledMuseumTurret.html, and the#astrolabetakes you directly partway into this longfile to the astrolabe stuff in yourbrowser.
Windsock is a piece of software thatyou must have on your computer toenable it to set up the TCPIIP stacks andmagic unless you have a UNIX box;then I don't think you need a Windsock.The name must be a metaphor or allu-sion to something about catching datapackets on the wind or something, Isuppose. Anyway you have to have oneor Netscape generally won't even
See MORE WEB, page 5
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by Wayne H. Warren Jr.
USNO and NCA Celebrate Clark Refractor Centennial
On Friday evening, January 5, 1996,astronomers and guests from the U.S.Naval Observatory and the NationalCapital Astronomers gathered in Build-ing 1 (the main administration building)at USNO to celebrate the centennial ofthe historic 12-inch (30.5-cm) AlvanClark refractor now housed in the domeatop that building. Following remarksabout the history of this fine instrumentby the USNO Historian Steve Dick,USNO Superintendent Captain Kent W.Foster, USNO Scientific Director KenJohnston, and NCA member DanCostanzo, NCA President Wayne War-ren presented commemorative plaquesto USNO staff members Ted Raffertyand Richard Schmidt, who restored thetelescope from its constituent parts re-trieved from the US NO dump. Not onlydid they do this on their own time, but,although they were originally allocated$1500 by then Scientific Director GartWesterhout, following funding cut-backs, they were eventually allowed tospend only $500, an incredibly smallsum considering the telescope's presentcondition and historical value. The re-furbished instrument is now usedmainly for public viewing on USNOopen nights.
The mounting for the 12-inch was designed andconstructed byGeorge N.Saegmullerof GlennDale,Mary-I andand wascompleted in November,1892. The objective lens,made by Alvan Clark, wasinstalled on December 19,1895 and has a focal lengthof 180.6 inches (459 em),with a focal ratio of f115. A4.5-inch (ll.4-cm) guidetelescope by John Clacy ismounted on the main tube.
In addition to the su-perb optics of the 12-inchtelescope (it is said thatDavid Levy stated that its
images were the finest that he'd everseen in any refractor with which he hasobserved), the instrument was fittedwith an intricate set of "star dials" de-signed by the then Astronomical Direc-tor of the Naval Observatory, WilliamHarkness. These dials, which havesince disappeared, gave a direct me-chanical readout of right ascension anddeclination. Similar dials can still beseen on the 12-inch Saegmuller refrac-tor at Georgetown University, whichhas also been restored by Ted Rafferty.
The Clark telescope, along withothers at USNO, was used mainly toobserve satellites and diameters of plan-ets, double stars, minor planets andcomets, and lunar occultations of stars.It was used until 1957, when it was putinto storage, but it was reactivated in1962 and used until 1971 to observedouble stars. Charles Worley and DickWalker were the main observers duringthat period. C h a r I e stold me that the objec-tive was atpoint
S 0 m esent to
theMuffoletto
Optical Com-pany in Baltimore
for testing. The reportstated that, on-axis, the
Clark objective gave thefinest images of any
that they had evertested. The tele-
scope was disas-sembled,crated, andmoved in 1971to a storage area
outdoors, where itsuffered exposure
damage over the years.In 1980, Ted Raffertyand Rich Schmidt re-stored the instrumentand it was remountedatop the main build-ing. The engravingshown with this ar-ticle was takenfrom a book on as-tronomical in-
Welcome New Members
Harold & Mary Birch3330 N. Leisure World Blvd., #906Silver Spring, MD 20906-5653
Ross S. Gersten1011 Elm Ave.Takoma Park, MD 20912
Mark Miller741 Monroe St., #203Rockville, MD 20850
Sherry Patterson10802 Henderson RoadFairfax Station, VA 22039
Adam Sieminski, III2930 Brandywine St., NWWashington, DC 20008-2138
John C. & Bobbie Stewart1812 Monroe St., NWWashington, DC 20010-10 15
struments published in Germany in1899. It shows the telescope as it lookedwhen originally mounted in the rooftopdome. The engraving, as well as muchof the information in this article, wasadapted from an anonymous write-upavailable at the celebratory gathering.
Following some refreshments,most attendees proceeded up to the roofof Building 1 to observe with the tele-scope. Although the seeing was not asgood as it could have been, I was im-pressed with the quality of the imagesand the instrument's resolution. It is noexaggeration to say that one of the tar-gets, a double star with separation 2seconds of arc, appeared as a star ofseparation about 20 seconds of arc doesin my 8-inch (20.3-cm) Celestron. Thedetail on the surface of the Moon wasquite extraordinary.
The NCA wishes to thank theUSNO staff for the opportunity to par-ticipate in this celebration. I wouldpersonally like to thank Dan Costanzoand Jim Roy for doing most of the worknecessary on NCA's part to arrange thegathering. The cake that Mr. Roy hadmade, which contained a fine, sugaryreplica of the 12-inch telescope, was notonly beautiful, but tasted good too.
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NEAR Watch #1By Daniel Costanzo
This month opens the launch windowfor NEAR, the Near-Earth AsteroidRendezvous mission. NEAR inaugu-rates the first of NASA's DiscoveryProgram missions extolling the new-found virtues of a "faster, cheaper, bet-ter" approach to Solar System explora-tion. NEAR will be the first test of thisphilosophy in the planetary missionarena.
Among its many other firsts, theNEAR mission involves the first flybyof a C-class (carbon-rich) asteroid (253Mathilde), a swingby of Earth, and thefirst rendezvous with a near-Earth aster-oid (433 Eros). If this rendezvous issuccessful, then NEAR will become thefirst spacecraft to orbit a small SolarSystem body, opening a whole new eraof exploration.
The NEAR mission is particularlyimportant to NCA because longtimeNCA member David Dunham is one ofthe key members of the NEAR MissionDesign Team at The Johns HopkinsUniversity, Applied Physics Labora-tory. This past October 7th he gave athorough, enjoyable, and informativepresentation to NCA on NEAR and hisrole in it. It was one of those rareinstances where NCA heard a lectureabout a mission before it occurred. Athorough review of Dave's October pre-sentation is forthcoming from me. But Iprefer to do things the Soviet way: don'tgive all the details until after a mission issuccessfully launched. So with Dave'sconcurrence, I have decided to providethis review after the launch is attempted.
NEAR's sixteen day launch win-dow runs from February 16 throughMarch 2, which should be enough,weather permitting, to allow a launch to
MORE WEB, from page 3
bother to install itself on your computerwithout telling you to go out and get onefirst. Windsocks can be downloaded forfree if you don't already have one, butyou of course have to know how to dothis.
GIF, JPEG or JPG, MOV, MPEG,or MPG, VOC, WAVE, 8SVN, HSN,COXL, ILBM, Targa, FIXT, ANIM,and WPG are all file extensions likehtml in Index.html that give some infor-mation to the viewer, browser, or playerabout what type of file it is receiving andwhat it should do with it. GIF and JPEGor JPG are picture files. MOV areQuicktime movie files. MPEG or MPGare another type of movie, animationfile that require a different viewer. VOCand WAVE are sound files that requireplayers and speakers to listen to. As for8SVN, HSN, COXL, ILBM, Targa,FIXT, ANIM, and WPG, they are rarerfile types that do various things that youwill encounter less often. Currently filetypes allow only two of the five humansenses to be addressed over the Internet,sight and sound. I will leave to yourimagination the file extensions and de-vices that would make for a more inti-mate computer experience includingtaste, smell, and touch.
So much for buzz words; think
STARS. Any NCA member who canwrite HTML code and is willing to helpmaintain and improve the NCA homepage should e-mail to me code frag-ments or entire pages. Any NCA mem-ber who, while browsing the WWW,comes across a URL that is not alreadyreferenced on the NCA home page thatthey think is generally useful to otherNCA members should e-mail me theseURLs. You can send me e-mail directlyin your WWW browser while viewingNCA's home page by clicking on the"Send e-mail to Harold Williams" tag atthe bottom of the NCA's home page.
As usual, we are indebted to NIHand NCA member Jay Miller for arrang-ing to meet at NIH, where he works. Ourtwo computer network engineers wereJay Miller and Tom Van Flandern. Bothmade multiple trips to the Lipsett am-phitheater weeks in advance of our pro-gram testing computers, network con-nections, and video display projectionscreens so every thing would run assmoothly as it did. The meeting bless-edly adjourned just before the largesnowfall began. Leith Holloway,NCA's meteorologist and secretary,checked several times during the meet-ing to make sure it had not yet started tosnow.
take place. The first eleven days of thiswindow can support a Mathilde flyby.Each individual day's launch windowlasts only twenty seconds. But the mag-nificent Delta booster can be launchedto within 0.01 seconds of the neededmission time. So this is fully within itscapabilities. As the flagship of the Dis-covery series, NEAR is the first plan-etary mission using the Delta. But whilethe Delta has one of the best launchingsuccess records of any rocket known,there have been failures. However,should NEAR sail off successfully, thisinstallment will inaugurate a regular se-ries of updates on the mission in StarDust, as this wonderful little "astrobot"sails forth on a voyage of Cosmic Dis-covery through the Solar System.
So let's all wish the best of luck toDave and the NEAR team, which in-cludes all of us, who support and fundthis essential and pioneering work.
Astronomical CalendarStill Available
The "Astronomical Calendar" for 1996,is available for $19.95. If you wish toorder a copy, please inform WayneWarren (NCA President). The price ofthe calendar goes down to $15.95 whenfour or more are ordered. For moreinformation: 3011474-0814
Newsletter Deadline forMarch Star Dust
FEBRUARY 15,1996
*** DO NOT BE LATE!!! ***
February is a short month. We needeveryone to work together. Please sendyour submissions in on time so that allNCA members will receive newsletterson time. Send your submissions to Gary& Alisa Joaquin, at 7821 Winona Ct.,Annandale, VA, 22003.
Leave a message on voice mail 703/750-1636 or send an ASCII file via e-mail at [email protected] [email protected] or fax to703/658-2233. Submissions must be ontime or they may not get in.
Page 5
ASTRONOMY NEWS UPDATEThe American Institute of Physics Bulletin of Physics News Number 255 January 19,1996
by Phillip F. Schewe and Ben Stein
Waterworlds: New Extrasolar Plan-ets have been discovered, and theymight support liquid water. Scientistsdiscussing the new observations at thisweek's meeting of the American Astro-nomical Society in San Antonio, Texassense that with solar systems other thanour own available for inspection, a newera in astronomy is opening up. Thisstudy of regular planets orbiting Sun-like stars (planets around pulsars weredetected a few years ago) began only inOctober 1995 with the discovery of aplanet around the star 51 Pegasi (Update246). That planet orbits its star at aradius of only 0.05 AU (an astronomicalunit is the distance between Earth andSun), making it very hot 1000° C (1830°F) and inhospitable for life. GeoffreyMarcy of San Francisco State an-nounced at the AAS meeting the discov-ery of two planets, both about 35 lightyears from Earth. One orbits the star 70Virginis at a distance of 0.43 AU with aperiod of 116 days; it has a mass ofabout 8 or 9 Jupiters and a surfacetemperature of about 83° C (185° F).Liquid water and conceivably lifeforms could be sustained at such aplanet or on a nearby moon, Marcysaid. The other planet orbits the star47 Ursae Majoris at a distance of 2.1AU wi th a period of 1100 days. It hasan estimated mass of3.5 Jupiters anda surface temperature of -90° C(-130° F). Marcy notes that somezones in the planet's atmospherecould harbor liquid water. Marcyhinted that his long-term study of 120nearby stars, carried out at the LickObservatory, would soon yield moreplanets. Basically, his evidence forplanets consists of slight modula-tions in the light coming from thestars as a result of the tug betweenplanet and star. Meanwhile, Christo-pher Burrows of the Space TelescopeScience Institute reported that the starBeta Pictoris (see figure on page 8),whose circumstellar dust disk has longbeen thought of as a possible nursery forplanets, did in fact possess a Jupiter-sized planet. The evidence for this, heargued, was a warping of the inner part
of the dust disk caused by the tidaleffects of a presumed planet orbiting inthe clear zone between the star and theinner edge of the dust disk.
The Hubble Deep Field (HDF), a pic-ture of a tiny patch of sky taken by theHubble Space Telescope, is the deepestoptical image of the Universe ever re-corded. Actually, it would be moreaccurate to say that the HDF has cap-tured the faintest galaxies (down to anunprecedented 30th magnitude) ratherthan the deepest or furthest galaxiesbecause the distances to many of theobjects are not yet known. Still, if asexpected deepness goes with faintnessand if thereby the image serves partly asa snapshot of the Universe at a very earlytime in its history, then it is significantthat the density of galaxies in the field isquite high; an estimated 1500 of alltypes and shapes crowd the frame. Thiswould suggest that telescopically as-
tronomers had not yet glimpsed the ep-och of the first galaxies. The observa-tions were carried out over a ten-dayperiod in December 1995 and used fourwavelength bands in order to achieve atrue color image.
The First Direct Image of the surfaceof a star other than our Sun was reportedby Andrea Dupree of Harvard-Smithso-nian. The surface of the star, Betelgeuse,had been indirectly imaged earlier usingspeckle interferometry, in which manybrief exposures are added up to make acomposite image. Dupree's picture (seefigure below, made with the HubbleSpace Telescope, confirm previous sus-picions that Betelgeuse's surface exhib-its a giant bright spot. According toDupree, the spot is 2000° K (3140° F)warmer than its surroundings and thatthis might be indicative of a new physi-cal phenomenon at work in some stellaratmospheres.
This is the first direct image of a star other than the Sun, made with NASA'sHubble Space Telescope. Called Alpha Orion is, or Betelgeuse, it is a bright redsupergiant star (shown here in black and white) marking the shoulder of theWinter constellation Orion the Hunter. The Hubble image reveals a hugeultraviolet atmosphere with a mysterious hot spot on the stellar behemoth'ssurface. Credit: Andrea Dupree (Harvard-Smithsonian Center for Astrophysics),Ronald Gilliland, Space Telescope Science Institute (STScI), NASA and theEuropean Space Agency (ESA).
Page 6
••Earth is the cradle of humanity, but we cannot stay in the cradle forever."Georg A. Donde (via Harold Williams)
Wednesday, January 17, 1996Time of press conference at the San Antonio meeting of The American Astronomical Society
Released jointly by University of California Berkley and San Fransisco State University
1117/96-File #14301Contacts: Robert Sanders, UC Berkeley - Voice: (510) 643-6998,
E-mail: [email protected] Polidora, SF State - Voice: (415) 338-3053
E-mail: [email protected]
Discovery of Two New Planets - thesecond and third within the last threemonths - proves they aren't rare in ourGalaxy.
San Antonio - Astronomers have dis-covered two new Jupiter-sized planetswithin about 35 light years of Earth,both at temperatures that mean theycould harbor water in liquid form.
The discoveries were announced Janu-ary 17, 1996 at a meeting of the Ameri-can Astronomical Society in San Anto-nio, Texas, by astronomers GeoffreyMarcy, a professor of physics and as-tronomy at San Francisco State Univer-sity and a visiting scholar at the Univer-sity of California at Berkeley, and PaulButler, a postdoctoral researcher with ajoint appointment at UC Berkeley andSF State. Marcy and Butler were theones who last year confirmed the firstdiscovery of a planet outside our SolarSystem, 51 Pegasi. "After the discoveryof 51 Peg everyone wondered if it was afreak, a one in a million observation,"Marcy said. "The answer is no. Planetsaren't rare after all."
The two new planets were foundaround the stars 70 Virginis, in the con-stellation Virgo, and 47 Ursae Majoris,in Ursa Major. Both stars are visible tothe naked eye, but the planets are toosmall and dim to be seen against theglare of their parent star. Neverthelessthe planets create a telltale wobble in thestars' motion, which the astronomerswere able to detect with sensitive equip-ment mounted on the 3-meter (120-inch) Shane reflector telescope at theUniversity of California's Lick Obser-vatory.
"These new discoveries are impor-tant because they spawn a new subfieldof astrophysics, the study of planetarysystems," Marcy said. "We can nowprobe the characteristics of these plan-ets, such as their orbits and masses."
Discovery of the first extrasolarplanet was announced Oct. 6 at meetingin Florence, Italy, by Michel Mayor andDidier Queloz of the Geneva Observa-tory in Switzerland, and confirmed aweek later by Marcy and Butler at LickObservatory. Circling the star 51 Pegasiabout 40 light years distant, the planetwas unofficially dubbed Bellerophonby Marcy, in keeping with the name 51Peg B given by Mayor and Queloz, andthe convention of naming planets afterGreek and Roman mythological figures.Bellerophon was a Greek hero who rodethe winged horse Pegasus to slay thefire-breathing Chimera. UnlikeBellerophon, which is about half themass of Jupiter and orbits its star in 4.3days - so close it is baked to 1000° C(1800° F) - the two new planets areseveral times the mass of Jupiter andorbit their stars at a distance typical ofour own Solar System.
The planet around 70 Virginis or-bits the star in an eccentric, elongatedorbit every 116 days and has a massabout nine times that of Jupiter. Usingstandard formulas that balance the sun-light absorbed and the heat radiated,Marcy and Butler calculated the tem-perature of the planet at about 85° C(185° F). "That's cool enough to permitcomplex molecules to exist, rangingfrom carbon dioxide to complicated or-ganic molecules," Marcy said. "Andbecause 85° C is below the boiling pointof water, this planet could conceivably
have rain or even oceans." The star 70Virginis is nearly identical to the Sun,though several hundred degrees coolerand perhaps three billion years older.
The planet around 47 UrsaeMajoris was discovered after analysis ofeight years of observations at Lick. Itsperiod is a little over three years (1100days), its mass about three times that ofJupiter, and its orbital radius about twicethe Earth's distance from the Sun. Thisplanet, too, probably has a region in itsatmosphere where the temperaturewould allow liquid water. "There isgoing to be a zone where a cauldron oforganic molecules cooks with water,"Butler said. "This system is the closestthing we've seen to anything like ourown Solar System."
Marcy notes also that during theirrecent observations they failed to detecta second planet around 51 Peg, in appar-ent contradiction to data obtained by theSwiss team that discovered it.
The San Francisco State and Uni-versity of California at Berkeley as-tronomers expect to announce the dis-covery of more new planets in thecoming years, now that they have per-fected a unique system for detecting thetiny wobbles in distant stars that indicatethe presence of a planet. The two startedtheir efforts in 1987 and have beenmonitoring 120 stars - all between 10and 100 light years from Earth - for upto eight years in search of periodicchanges in the star's speed. The wobblein a star's velocity is determined fromthe Doppler shift in the star's spectrum.The Doppler shift is a shift of wave-length or color caused by the motion of
See NEW PLANETS, page 8
Page 7
NEW PLANETS, from page 7
a star toward or away from the observer.Objects moving away have their entirespectrum shifted toward the red, whilethose moving toward us have their spec-trum shifted toward the blue.
Within the past year and a halfMarcy and Butler have refined theirtechnique to the point where they canmeasure this velocity within an accu-racy of three meters per second - thespeed of a brisk walk. Jupiter, for ex-ample, produces a 12.5 meter per secondwobble in the Sun's orbit. With a fewmore years of observations, Marcy said,the team could detect a Jupiter-sizedplanet orbiting a distant sun - assum-ing it is located at Jupiter's distancefrom our Sun and has a similar period ofabout 12 years. They achieve this preci-sion by putting a glass chamber of iodinegas in front of the telescope so that lightfrom the star passes through and is partlyabsorbed, superimposing the absorptionspectrum of iodine onto that of the dis-tant star. Spreading out the composite
spectrum and cutting it into chunks, theythen measure how much the starlightspectrum has shifted to the blue or redrelative to the known spectrum of io-dine. Each chunk provides an estimateof the shift, and averaging the results of500 such chunks yields a very precisemeasurement of the Doppler shift,Marcy said. They were greatly aided inthese measurements by a state-of-the-art spectrometer on the Lick telescopethat was recently refurbished by as-tronomer Steve Vogt of DC Santa Cruz.
Geoffrey Marcy and Paul Butlercan be reached by calling the PublicInformation Offices at DC Berkeley orSF State, or via e-mail [email protected] [email protected].
Graphics, photos, and a short video alsoare available from the Public Informa-tion Offices, phone: 510-642-3734,Fax: 510-643-7461. Or download themfrom the WWW site http://pio06.urel. berkeley .edu/.
WWWBookmarks of the
Month
Another Planet About to be Discovered?You Decide
This Hubble image shows for the first time the inner region of a dust disk aroundthe bright Beta Pictoris. This region has long since been hidden from ground-based telescopes because of the glare from the central star. By looking at thedotted line, note how the disk is slightly warped. If the warp was there when thestar was formed, it would long since have flattened out, unless maintained by thegravitational pull of a planet. Credit: Chris Burrows, Space Telescope ScienceInstitute (STScI), the European Space Agency (ESA), J Krist (STScI), the WideField Planetary Camera 2 (WFPC2) IDT team, and NASA. (Note: The bottomimage though viewed in black and white, shows the color spectrum. The colorspectrum helps to see that the disk is slightly warped by the lack of symmetry.)
Jay Miller has come across two moreweb sites for exploration. The first isfrom Australia and the second fromFrance.
http://www /ozemail.com.au/-putney /Woodlands
http://www.alpes-net.fr/-Lp_desm/sunspots.html
This may beome a new column featurefrom time to time. If you find a web sitethat other members may enjoy, thinkabout publishing it here so others can tryit. While you are exploring, if you findany useful information that would beworth publishing in Star Dust, down-load a copy with a short note to theeditors. Thank You.
1996Observer's Handbook
Copies of the 1996 Observer's Hand-book, published by the Royal Astro-nomical Society of Canada, will be onsale for $12 apiece at the NCA monthlymeetings until they are sold out. Thismeans you can obtain this fine annualpublication at a substantial discountthrough NCA, making it another astro-nomical shopping benefit ofNCA mem-bership. Please bring a check made outto "National Capital Astronomers"rather than cash. If you wish to buy acopy but cannot attend the meeting,please call me evenings or weekends tomake other arrangements. Thanks.
Jeff Norman, (202) 966-0739
Don't throw this newsletter away. Ifyou are finished with it, pass it on tosomeone else to read. If not, thenrecycle it. It's right for the environ-ment.
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Getting to the NCA Monthly MeetingMetrorail Riders - From Medical Center Metro Stop: Walkdown the hill, pass the bus stops and turn right at the anchoronto Center Drive. Continue uphill to Building 10 (walkingtime about 10 minutes), the tallest building on campus. Also,the 12 bus line connects the Bethesda (7: 16 PM) and NIH(7:23 PM) Metro stops with Building 10 (7:25 PM).To North China Restaurant-Take Wisconsin Avenue to-ward Bethesda and bear right onto Woodmont (or take thenext right onto Battery Lane). Follow Woodmont to OldGeorgetown Road and make a right. The restaurant is a fewblocks on the left (7814 Old Georgetown Road). Alterna-tively, turn right on Cordell from Woodmont and proceed afew blocks to Old Georgetown, where you will come out rightnear the restaurant. There is parking around the corner on aside street. Seats are not guaranteed after 5:30.
Star Dust is published ten times yearly (September throughJune) by the National Capital Astronomers, Inc. (NCA), anon-profit, astronomical organization serving the entireNational Capital region, and beyond. NCA is the astronomyaffiliate of the Washington Academy of Sciences and theNational Capital region's representative of the Interna-tional Dark-Sky Association. Phone Numbers: 301/320-3621 or 703/841-4765. President, Wayne H. Warren, Jr.;301/474-0814. Deadline for Star Dust is the 15th of thepreceding month. Editors Alisa & Gary Joaquin, 7821Winona Ct., Annandale, VA 22003, 703/750-1636, E-mail-see deadline box for new address. Daniel J.Costanzo,Editorial Advisor. Star Dust © 1995 may be reproducedwith credit to National Capital Astronomers, Inc.
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Enter Building 10 from north (MainEntrance); passing through the doubledoors. Turn left and follow signs forLipsett Auditorium. If unsure, ask fordirections at the Information BoothInside Main Entrance.
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