1 July 1999 -------------- No. 80
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ALMA
Evolution of the MMA to ALMA
The Millimeter Array (MMA) project passed a significant milestone onJune 10, 1999,whenrepresentatives from the U.S. National Science Foundation (NFS) and fromseveralEuropeanscientific agencies signed a Memorandum of Understanding (MOU) forcooperation ondesignand development of the Atacama Large Millimeter Array (ALMA). ALMA isto be anequalpartnership between the NSF on one side and a collaboration of Europeaninstitutionson theother; ALMA will subsume the MMA Project and the Large Southern Array(LSA) Projectin theU.S. and Europe respectively. The participating institutions on theEuropean sideare: TheEuropean Southern Observatory (ESO), the Centre National de la RechercheScientifique (CNRS,France), the Max-Planck-Gesellschaft (MPG, Germany), the NetherlandsFoundation forResearch in Astronomy and Nederlandse Onderzoekschool VoorAstronomie, and theUnitedKingdom Particle Physics and Astronomy Research Council.The goal of ALMA is an array of 64 antennas of 12 meters diameter.Recognizingthe increasedscientific opportunity that such an array presents over the existing MMAand LSAconcepts, boththe U.S. MMA scientific advisory committee (the MAC) and the EuropeanLSA scientificadvisory committee (the SAC) have consistently endorsed the merger ofthe twoprojects. Whileeach side will be entitled only to half the time on the ALMA, that halfprovides anet increase incapability. ALMA is an example of a partnership of augmented benefit toallparticipants.
The MOU signed June 10 commits both sides to a common design anddevelopmentphase forALMA. There is a stated intent of both sides to continue to theconstruction phaseof ALMA,but no such commitment to do so--at least not yet.
The MOU sets up an organization and oversight structure for ALMA.The top levelof thatorganization is the ALMA Coordination Committee (ACC), a board of twelvemembershalf ofwhom are European appointees and half are appointed by the NSF. Underthis Board istheALMA Executive Committee (AEC)two managers from the LSA and twofrom theMMA--whoare charged with defining and managing the ALMA Design and Developmentwork program.TheAEC has until October 10, 1999, to present that work plan to the ACC forapproval;onceapproved, the AEC will implement the plan. On or before May 2000 theAEC is tosubmit to theACC a draft of the construction and management plan for ALMA. In thesucceeding sixmonthsthe NSF and the European institutions will negotiate their commitmentsto that plan.If all goeswell, construction will begin in 2001, just as has been planned for theMMA with nodelay.
The U.S. side of ALMA will be the MMA Project renamed to ALMA/US butotherwiseunchanged. In particular, ALMA/US will remain an integral facility ofthe NRAOidentical in allinstitutional respects to the VLA, VLBA, and the GBT. Theuniversity-basedMillimeter ArrayDevelopment Consortium (MDC) will remain in the management structure ofALMA/US andwillcontribute, as previously planned, throughout the development,construction, andoperationalphase of ALMA.
R. L. Brown
October Conferenceon 'Sciencewith The Atacama LargeMillimeter Array'
Science with the Atacama Large Millimeter Array (ALMA) will be aninternationalconference onthe science which will be produced by ALMA, which might combine Northand SouthAmerican,European and Asian plans for construction of large arrays of millimetertelescopesinto a singlelarge project. Please see the accompanying article announcing thesigning of theMemorandum ofUnderstanding leading to the ALMA design and development stage.The meeting will be held October 6-8 in Washington, D. C. The purposeof theconference will beto highlight the science that this powerful world array will accomplish,withparticular focus on:
- Investigation of galaxies near the time of their formation,
- The formation of stars,
- Detection and study of planets and disks forming them around nearby stars,
- Study of the origin, distribution and evolution of the elements and their isotopes.
It will begin with a reception and demonstration for members ofCongress in theHouse ScienceCommittee Room of the Capitol at 5:30 p.m. Wednesday, October 6, 1999.
Lectures and posters will be presented at the Carnegie Institution ofWashington,1600 P St. NWon October 7 and 8. Accommodations have been arranged at the nearby OmniShorehamHotelfor the period including the nights of October 5 through October 9.Information on reserving aroom at the special Associated Universities rate is at the web site.The room blockwill be closedon August 20, 1999.
A press conference will begin the proceedings, to explain the worldcollaborationto the media.This will be held in the Board Room of the Carnegie Institution ofWashington at 8a.m. on October 7.
The conference will be organized and hosted by AssociatedUniversities,Incorporated and theNational Radio Astronomy Observatory.
Invited speakers include; Sargent, Blain, Guilloteau, Scoville,Thornley,Genzel*, Dutrey, Boss,Mundy, Jewitt, van Dishoeck, Menten, Evans, Fukui, Plambeck, Andre,Crutcher,Yamamoto,Olofsson, Tielens, Shu, and Millar. (*= tentative).
Science with the Atacama Large Millimeter Array will be limited to200participants. Informationon the conference will be posted on the Millimeter Array website with theURLhttp://www.mma.nrao.edu/science/science99.html
H. A. Wootten
GREEN BANK
Green Bank Telescope
The rework of the permanent support for the backup structure wascompleted when thelast weldwas made in mid-May. The final welding inspection has been made and allweldspassed.The transferral of the load of the reflector backup structure (BUS)from thetemporary supportsto its permanent supports have been a long process. The contractor,unfortunately,prolonged theoperation when, in an effort to save time, removed the temporarysupports out of theprescribedsequence. This caused an unanticipated redistribution of loads, causingsome backchord membersto bend and causing one to buckle. The contractor has since restored theBUS to itsoriginalconfiguration, performed an engineering analysis to determine why thefailuresoccurred, anddeveloped a procedure/method for transferring the loads, which was thensuccessfullyaccomplished.
The shape of the structure was checked after the temporary supportswere removed,and theweight of the BUS was carried by the permanents. The position of theactuators wasfound tovary by only a small amount from the dimensions measured when supportedby thetemporaries.
Installation of the Vertical Feed Arm & the Upper FeedArm -The photograph in theprevious Newsletter showed the Vertical Arm complete through modules H.Since then,themembers of the VFA module M were bolted to the Upper Feed Arm, and theUpper FeedArmwas trail assembled to the structure made up of modules K and L, on theground. Thistrial wentwell, and preparations for the lift of K and L were completed. Liftingof moduleswas delayedwhile their alignment was checked and confirmed, but on June 2 themodules wereraised intoplace. Placement of the fill-in members which create the bridging moduleJ iscomplete and theirwelding is in process. The telescope is shown in the figures (as of June10). It isnow planned toraise the Feed/Receiver Room late in June. Beginning in mid-July, theUpper Feed Armwill beraised and connected into place.
Servo - The structure was rotated in elevation forthe firsttime on May 19, 1999, when it wasmoved 12 degrees to position it for the installation of the middleportion of theVertical FeedArm. This important test was carried out using the portable maintenanceunit (PMU)to controlthe elevation motion. Both motor current and voltage were monitored,and allmovement of thestructure was smooth, silent, and without vibration. All eightforty-horsepowerelevation motorswere used. Motor currents were predicted accurately by the analysis ofcounterweightout-of-balance and motion was readily controlled to 1/50 of an inch.
Surface Panels - Measurement of GBT panels iscontinuing at theRSI facility in Sterling, VA. NRAO inspections are of two types. In one, surface accuracy of theunpainted panelsis analyzedon the basis of measurements provided by the manufacturer, and a numberof panelsselected byNRAO from the tier under review are measured again, with NRAO witnessingthemeasurements. If it is determined that the measurements agree with those provided bythemanufacturer, and ifthe table of measurements for the tier shows that the entire tier iswithin theaccuracy specified inthe contract, then the panels of a tier are accepted. By May 25, 1188panels (59percent of thetotal of 2,004) from 22 tiers passed this requirement. The second typeofinspection involvespainted panels. As before, selected panels of a given tier areinspected, and allpanels must passscrutiny for the tier to be accepted. For the sample selected, the paintthicknessis measured atmany positions using a gauge provided by NRAO.
R. D. Hall and D. E Hogg
First Field TestsofRangefinder Metrology
A milestone for the GBT laser rangefinder metrology program was met onWednesdayevening,June 23, 1999.Nine of the twelve ground rangefinders were mutually scanning andranging to oneanother. Apair of rangefinders also ranged to a fixed target retro-reflector 1.3km distantfrom the GBT,while a second rangefinder pair ranged to the single ballretro-reflector mounted onthe GBT feedarm. A complete set of range samples (AZ range pairs) was taken everytwo minutes,for a totalobservation time of four hours. Temperature, barometric pressure, andrelativehumidity datainputs from multiple stations were logged for each set of range scans.
A laser target acquisition control algorithm developed by RamonCreager wasoperational, toelectronically locate and lock the rangefinders onto their targetsbefore theevening's scans started.The range, data, and electronic rangefinder diagnostic's data, werelogged andplotted during themeasurement run. The diagnostic's data consist of received beam signalintensityand return signalphase, and atmospheric data. A large data set was obtained, which willbe analyzedindependentlyby Don Wells, and by the antenna metrology group, to obtain accuratemeasurements ofrangefinder locations.
In the next two months, the last three rangefinders will becomeoperational,pending running ofcables through the recently installed conduits. Additional targetretro-reflectorswill be placed onthe telescope. At that time a complete test of the ground rangefindermetrologysystem will beconducted.
M. A. Goldman & R. H. Hall
40th Anniversary ofthe TatelTelescope and First Science at NRAO
The Howard E. Tatel Radio Telescope, built in 1958, was the first majorradiotelescope atNRAO. Known also as 85-1, it was the first of three 85 foot telescopesof similardesign built atGreen Bank by the Blaw-Knox Corp. of Pittsburgh, Pa. In 1964, when theNRAO decidedtobuild an interferometer, the Tatel Telescope became the fixedelement in theNRAO 3-elementinterferometer system.Howard E. Tatel worked for the Carnegie Institute Department ofTerrestrialMagnetism (DTM)in the 1950s and collaborated with the Blaw-Knox Company of Pittsburghto design atelescopefor DTM. Blaw-Knox had also received telescope orders from NRAO, theUniversity ofMichigan, and the Jet Propulsion Laboratory. Tatel's concept used largediametergears for thetwo axes to provide high precision at relatively low cost. Bob Hall, whois now theGBT projectmanager, was then manager of the antenna division at Blaw-Knox. Heexpanded Tatel'sconcept,generated a practical working design, and supervised the construction ofthesetelescopes. Tateldied on a field trip in 1957 and never saw the completion of histelescopes. 85-1was dedicated inOctober of 1958, and named in his memory.
The telescope began continuous operation in April of 1959. Fred Crewsrecalls (in'TheObserver,' March 31, 1964) that the first observations were done onFriday,February 13, 1959. 'Initially there were only two operators (Fred Crews and Bill Meredith),who worked12 hourshifts, keeping the telescope going 24 hours a day except for weekendswhen thescientists didtheir own observing.'
The year 1999 is a significant 40th anniversary not only because theTatelTelescope beganregular use, but also because the first scientific results were obtainedin 1959, asa result of thecompletion of the Tatel. According to the first NRAO annual report (July1959), thestaffastronomers in 1959 were David Heeschen and Frank Drake. (It is thusquiteappropriate thatFrank Drake was chosen as the Jansky Lecturer for this year.) Visitingastronomersin 1959included George Field, Hein Hvatum, T. K. Menon, Donald Osterbrock,Grote Reber,MortRoberts, and Gart Westerhout.
The first receivers were for bands at 440 MHz, 1.1-1.5 GHz, and 8GHz. Thefirst observingprograms included studies of the planets Jupiter and Venus (Drake), thefirstdetailed maps of theGalactic center (Drake), attempts to detect 21 cm line emission inglobular clusters(Roberts), andmulti-wavelength studies of supernova remnants (Heeschen). Menonstudied theCygnus loopand the Orion nebula, Field observed Cygnus A, Heeschen surveyed spiralandelliptical galaxies. Drake's famous project OZMA was started in 1959.
Today the Tatel Telescope is still in continuous use as part of theGreen BankInterferometer,now funded partly by NASA for studies of x-ray and gamma-ray binarystars.
Fred Crews concludes, in the 1964 Observer article,'The 85 Foot TatelTelescope has now beenin operation for five years. Its life expectancy is 20 years.' Buttoday, in 1999,the telescope hasbeen productive for twice its expected lifetime, thanks to HowardTatel's initiativeand Bob Hall'srugged design. How many of us can say the same?
F. D. Ghigo
Last VLBIObservations With 140Foot
On June 17 at 7:00 UTC the final VLBI observations with NRAO's 140 FootTelescopewerecompleted. The 140 Foot played an integral role in the earlydevelopment of VLBI.From itsfirst fringes on a baseline of 650 meters to its last fringes onbaselines up to 3Earth radii, the 140Foot has served the VLBI community well.The first attempts to use the 140 Foot for VLBI observations were inJanuary1967. The firstfringes found with the 140 Foot were detected on March 5/6, 1967 with abaseline of650 metersbetween the 140 Foot and the Tatel Telescope (85-1). These observationsused theMark Irecording system and 720 kbps recording onto 7-track tapes. In June1967 the firstfringesbetween the 140 Foot and an antenna at another observatory (Haystack)wereobtained. The firsttranscendental fringes were found in July 1967 using the 140 Foot andthe 26 metersatHat Creek. The first intercontental fringes were found using the140 Foot, Haystack, Hat Creekand Onsala. The first fringes found with an antenna in Russia also usedthe 140Foot.
The 140 Foot has made many notable VLBI observations. The first realtimefringes in VLBIobservations were found using satellite communications to relay the IFand LOsignals betweenthe 140 Foot and Algonquin Radio Observatory in the mid-1970s. The 140Foot was oneof fivetelescopes dedicated to the first VLBI network organized in 1976. The140 Foot,Haystack, andHat Creek were used to make the first VLBI images of an OH maser. Thefirstmeasurements ofpulsar parallaxes were made using the 140 Foot, Arecibo, andOwens Valley. The140 Foot hasrecorded with nearly all types of recording systems - Mark I, Mark II,Mark III,VLBA, and S2systems.
The last VLBI observations with the 140 Foot were a part of amonitoring programfor source1928+738 as a part of a network including HALCA, the Japanese Space VLBIsatellite.Theinvestigators were D. W. Murphy (JPL), J. E. Conway (Onsala), A.Polatidis(Onsala), R. A.Preston (JPL), S. J. Tingay (JPL), D. L. Jones (JPL), D. L. Meier(JPL), H.Hirabayashi (ISAS), H. Kobayashi (ISAS), and Y. Murata (ISAS).
A. H. Minter
The Galactic PlaneSurvey
The images and source list from the first Galactic Plane (GPA) survey at8.35 and14.35 GHz arenow publicly available on line. The GPA survey is part of a program tomonitor thegalactic planeat 8.35 and 14.35 GHz for transient and variable sources. Thefirstimages of the galactic planecover the region|b| < 5, l = -15 to 255. These images have 11.17 arcm and7.25 arcmFWHM resolution at8.35 and 14.35 GHz respectively. These observations used the NRAO/NASAGreen Bank Earth Station to survey the sky simultaneously at these frequencies.
The first survey, GPA, covers 0.82 sr (6.5 %) of the sky. Thesurvey issensitive to discretegalactic and extragalactic sources. A source list is presented for all599 sourcesbrighter than0.9 ~ Jy at 8.35 GHz or brighter than ~ 2.5 Jy at 14.35 GHz.The FITS format images, residualimages, source lists, and archive data are allavailable at http://www.gb.nrao.edu/~glangsto/GPA/.
G. I. Langston & A. T. Minter
Green BankComputingDevelopments
We have decided to remove all Unix login accounts in Green Bankthat have notbeen usedrecently. There are two principal reasons for this. First, unused butactiveaccounts are a securityrisk. There can be unwanted intrusion into the computer systems withoutthe accountownerbeing aware of anything amiss. Second, most of the dormant accountsbelong tovisitingobservers. Many of these visitors' accounts have home directories on anold Sun atthe 140 FootTelescope. The home directories will have to be moved and the Unixenvironmentswill also needto be completely reconfigured for eventual use with the GBT. Theaccounts will bepurged insuch a way as to be simply restorable. If anyone, whose account has beenremoved,would like toretain it as it was, we will be happy to restore it to its originalstate - pleasesend a message toChuck Van Tilburg or Gareth Hunt. However, we expect that mostobservers will finditconvenient to have a new account with a completely fresh environmentwhen theyobserve withthe GBT.Observatory-wide, funds in the computer budgets are tight this year.However, wehave sufficientresources to upgrade the main Unix server (Arcturus). In addition, wewill be ableto replace fiveof the older public Suns with PCs running Linux.
The projection system in the new Green Bank auditorium is a veryflexible onebased on NTSC. For use with today's computer graphics, however, it does not havesufficientresolution, as wasclear during two GBT meetings last year. We have purchased a dedicatedprojectorwithimproved resolution and brightness to use for computer-basedpresentations.
G. C. Hunt
Busy Season forEducation
The NRAO staff at Green Bank have literally been running from oneeducationalproject to thenext this spring and summer!Once again, we worked with local seventh grade students on a six-weekastronomyprojectentitled 'Our Place in the Universe.' This year, all Green Bank seventhgradersspent the night atthe Observatory conducting research projects on The 40 FootTelescope,using our library andinteracting with staff astronomers. At the conclusion of their project,theypresented their findingsduring a colloquium held at the NRAO. This kind of 'extended visit' bystudents wasmuch morepopular this year. Since January 1999, nearly 700 students (from grade5 throughundergraduateastronomy students) have participated in research activities at theObservatory.
In May, we began our workshop series starting with Glenville StateCollegestudents. Preserviceteachers enrolled in the methods course at GSC spent the first week oftheirsemester at theNRAO . This field experience was essentially a compressed version of oursummerresearchinstitutes. Teams of students conducted research using The 40 FootTelescope andinteracted withscientist 'mentors' who assisted them with their projects. As the coursecontinuedback at thecollege, students designed a classroom research project, andfield-tested it in aK-12 classroom.
Also in May, NRAO-Green Bank hosted a three-day Chautauqua ShortCourse entitled'A RadioView of the Universe.' The Chautauqua Short Course Series is an NSFsponsoredprogramdesigned to update undergraduate college faculty members' knowledge inforefrontscienceresearch and teaching. A record 35 professors attended the course thisyear. Inaddition,University of Hawaii astronomer, Gareth Wynn-Williams, led a shortcourse at theObservatoryentitled 'Teaching Introductory Astronomy.' The two NRAO workshops areheldback-to-backso that participants can attend both, if desired.
The last two weeks of June brought 16 in service teachers to theObservatory forthe 'RARECATS' Research Institute. RARE CATS (a rather tortured acronym) standsfor RadioAstronomy Research Enhancing Coordinated and Thematic Science, whereCATS is theacronymgiven to the new West Virginia Science Curriculum. For two weeksparticipants gainfirst handexperience in conducting science research and improve their contentknowledge inastronomy. Project RARE CATS is a two-year summer/academic year program forparticipants.During asecond summer, participants return to Green Bank for the 'Hands-OnUniverse'TechnologyInstitute.
Hands-On Universe (HOU) is an image processing software package thatallowsteachers andstudents to analyze FITS format astronomy images. The software andcurriculum weredeveloped at the Lawrence Berkeley National Laboratory, and the University ofCalifornia atBerkeley. TwoHOU institutes are scheduled for this summer. The first of these tookplaceimmediatelyfollowing the June RARE CATS program. Participants in the HOU instituteobtain asite licensefor the software as well as a set of curriculum materials.
And finally, to bring you up to the present, the National YouthScience Camp willvisit theObservatory during the second week of July. First, a small group ofstudents willcamp overnightat The 40 Foot Telescope and make observations all night long. Theentire NYSCdelegation willvisit for a tour of the GBT on July 8. This event coincides with avisit to thesite from SenatorRobert C. Byrd (D-WV). Senator Byrd will address NRAO staff and theScience Campdelegation, and then join them for a tour of the GBT.
S. A. Heatherly
VLA
VLA-Pie Town Link
Work on the VLA-Pie Town link over the past few months has concentratedon thehardwarenecessary to upgrade the system, from one with a few antennas operatingwith oneintermediatefrequency (IF) channel, to a capability for using all 27 antennas andall four IFs.In addition, newoptical isolators have been inserted to prevent command dropouts.Measurements alsohave beenmade of the rate of change of the length of the 103 km fiber link(length increaseof approximatelyone micron per second as the ground temperature increased in the summermonths).Thismeasurement helps characterize the relative contributions of linkvariation andmaser differencesto frequency offsets between Pie Town and the VLA, needed to assesstherequirements forcorrection of these offsets.In June, new piggyback boards were installed on all VLA correlatorcards in orderto achieve anexpanded delay range of more than 800 microseconds for all antennas.These boardswill enableobserving anywhere in the sky, allowing compensation for the sum of thelink delayand thegeometric delay, which has a maximum value of approximately 670microseconds. TheVLAcorrelator has been operating with this new hardware since June 2; thechange iscompletelytransparent to observers. Test observations on the VLA Pie Townlink usingall four IFs areplanned for late July and throughout August, with a goal of obtainingsomepreliminary scientificobservations before the end of A configuration in late September.
J. S. Ulvestad
New MexicoComputingDevelopments
The transition from our old Auspex file server to the Network ApplianceFiler 720 isprogressingwell. Another milestone was reached when e-mail was moved from Arana(the Auspex)to zia. Zia, a SPARC 20, is taking over Arana's mail hub and administrativeduties. Weexpect to be ableto decommission Arana completely in the second half of 1999. This isimportantsince our currentAuspex operating system is not Y2K compliant.We have concluded the installation of the Pentium II 400 PCs runningthe Linuxoperatingsystem. It appears that in the current year we will not be able to addmore thanone or two ofthese systems. After almost one year of supporting this class ofmachines weconclude thatPentium based PCs running Linux are a good and fast alternative toclassicworkstations.
Over the next three months we intend to start upgrading our Solarisand Linuxoperating systems. Late this summer the AOC should begin upgrading all Linux systems toRedHat 6.1 andall Sparcsystems to Solaris 2.6 or 2.7. The upgrades are necessary for Y2Kcompliance aswell as thirdparty software compatibility.
We are currently testing JOBSERVE internally at NRAO. JOBSERVE is autilitywritten in Javaby Bill Cotton. It allows preparation of VLA OBSERVE files and willeventuallyreplaceOBSERVE. Advantages of JOBSERVE over old OBSERVE include its operatingsystem andkeyboard independence and its graphical user interface. We also intendto add thepossibility tocreate OBSERVE files for VLA observations which include the antenna atPie Town. Wehopeto announce the first public release of JOBSERVE later in 1999.
As part of the VLA online system upgrade and rewrite we have begun toconnect theVLAmonitor and control system to a VME/VxWorks computer system.Requirements documentsforthe VLA Expansion have been started, and a first draft of the computingplan for theVLAExpansion has been written.
G. A. van Moorsel
VLA ConfigurationSchedule
| Configuration | Startingdate | Ending date | ProposalDeadline |
| A | 18 Jun 1999 | 27 Sep 1999 | 1 Feb 1999 |
| BnA | 08 Oct 1999 | 25 Oct 1999 | 1 Jun 1999 |
| B | 29 Oct 1999 | 14 Feb 2000 | 1 Jun 1999 |
| CnB | 25 Feb 2000 | 14 Mar 2000 | 1 Oct 1999 |
| C | 18 Mar 2000 | 30 May 2000 | 1 Oct 1999 |
| DnC | 09 Jun 2000 | 26 Jun 2000 | 1 Feb 2000 |
| D | 30 Jun 2000 | 18 Sep 2000 | 1 Feb 2000 |
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The maximum antenna separations for the four VLA configurations are:A-36 km,B-11 km, C-3km, D-1 km. The BnA, CnB, and DnC configurations are the hybridconfigurations withthe longnorth arm, which produce a round beam for southern sources (south ofabout -15degreesdeclination) and extreme northern sources (north of about 80 degreesdeclination).
ApproximateLong-TermSchedule
| Q1 | Q2 | Q3 | Q4 | |
| 1999 | C,D | D | A | B |
| 2000 | C | C,D | D | A |
| 2001 | B | B,C | C | D |
| 2002 | A | A,B | B | C |
| 2003 | D | D,A | A,B | B |
Observers should note that some types of observations aresignificantly moredifficult in daytimethan at nighttime. These include observations at 327 MHz (solar andotherinterference; disturbedionosphere, especially at dawn), line observations at 18 and 21 cm(solarinterference),polarization measurements at L band (uncertainty in ionospheric rotationmeasure),andobservations at 2 cm and shorter wavelengths in B andA configurations(tropospheric phasevariations, especially in summer). They should defer such observationsfor aconfiguration cycle toavoid such problems. In 2000, the C configuration daytime will beabout02h RA and theD configuration daytime will be about 10h RA.
Time will be allocated for the VLBA on intervals approximatelycorresponding tothe VLAconfigurations, from those proposals in-hand at the corresponding VLAproposaldeadline. TheVLBA spends about half of available observing time in coordinatedobservations withothernetworks, with the scheduling dictated by those networks. In decreasingorder ofthe timedevoted to the observations, these are HALCA space VLBI, CombinedMillimeter VLBIArray,Global astronomical VLBI with the EVN, and geodetic arrays coordinatedby GSFC.
Any proposal requesting NRAO antennas and antennas from two or moreinstitutionsaffiliatedwith the European VLBI network is a Global proposal, and must be sent tothe EVNscheduler aswell as to the NRAO. VLBA proposals requesting only one EVN antenna, orrequestingunaffiliated antennas, are handled on a bilateral basis; the proposalshould be sentboth to NRAOand to the operating institution of the other antenna requested.Coordination ofobservations withnon-NRAO antennas, other than members of the EVN and the DSN, is theresponsibilityof theproposer.
B. G. Clark
A Celebration of 20Years ofObservations with the VLA
The NRAO and New Mexico Tech will jointly host a conference in Socorro,NM, entitled'TheRole of Gas in the Evolution of Galaxies.' The conference will run fromMay 20-24,2000, and isprojected to involve some 100-150 scientists.Please check out theconference web site at:http://www.aoc.nrao.edu/doc/vla/html/Y2K/hiconf.shtml. For further details contactMichaelRupen, Jacqueline van Gorkom, or John Hibbard.J. E. Hibbard
Graduate StudentVisits for 1-5Months at the AOC
Graduate students affiliated with U.S. universities are welcome to visitthe AOC forperiods of1-5 months. Visiting students will work on their VLBA or VLA data undertheguidance ofmembers of the NRAO scientific staff and then return to their homeinstitutions tocomplete thescientific work. This is an excellent opportunity for students to workone-on-onewith NRAOstaff to learn how to use the VLBA or VLA as part of their scientificrepertoire.Students maybring funding from their home institutions or may be awarded stipendsfrom NRAO.Awards willbe decided on a case-by-case basis. This visiting program willinitially emphasizestudents withVLBA data.10 Slot Mailbox Near Me Google Maps
Students or their faculty advisors interested in taking advantage ofthisvisiting program shouldcontact julvesta@nrao.edu, jwrobel@nrao.edu, or mgoss@nrao.edu.
J. M. Wrobel, J. S. Ulvestad
VLBA/VLBI
Space VLBI
VLBA participation in the Japanese-led international Space VLBI mission,VSOP, hascontinuedsince about the beginning of 1998 at a rate very close to NRAO'scommitment of30 percent ofscheduled observing time. Two recent outages caused by a failure inon-boardelectronics of fourmonths at the end of 1998, and three weeks in February-March 1999, havebeenexcluded incomputing this statistic.Beginning early in 2000, the pool of proposed observationsrecommended by theVSOP ScienceReview Committee will be exhausted, although some could not be observeduntil aslate asmid-2000 due to orbit evolution. New proposals for VSOP observationswill thus berequired inthe next few months. NRAO has requested that these proposals besubmitted andreviewedthrough the same mechanism used for VLBA and global ground-based VLBIobservations,withall proposals requesting VLBA resources thus being reviewed jointly.This newprocedure anddetails for implementing it, are under consideration by the VSOP missionand theVSOPInternational Steering Committee (VISC). It is hoped that a decisioncan be reachedin time fornew proposals to be submitted by 1999 October 1, so that some ofthese canstart being observedby 2000 January 1. Further information will be available as soon aspossiblethrough the VSOPNewsletter, the 'vlbi' e-mail list, or from the undersigned.
The VSOP mission has announced a symposium on 'High 'EnergyAstrophysicalPhenomenaRevealed by Space-VLBI,' to be held at ISAS January 19-21, 2000. Theprogram isexpected toinclude the following topics: high brightness temperature sources;intra-dayvariables; GeV andTeV gamma-ray sources; GHz-peaked-spectrum sources; structural changesrevealed bymonitoring; survey programs; and future prospects for Space VLBI. Theannouncement,whichincludes an Expression of Interest form due by July 30, 1999 may beaccessed at URLhttp://www.vsop.isas.ac.jp/Symposium.html.
J. D. Romney
New VLBA Servicesfor NoviceU.S. Users
The VLBA is instituting a series of new services for novice users of theinstrumentwho areaffiliated with U.S. institutions. 'Novice' users are defined as thosewho have usedthe VLBA nomore than once, and are not very familiar with the general techniques ofVLBI. Theymay bestudents, postdocs, faculty members, or affiliates ofnon-degree-grantinginstitutions. The newservices will be available for proposals submitted in advance of theOctober 1,1999, proposaldeadline.The primary new service that is being offered is a completescheduling anddata-calibrationservice, where the calibration includes all aspects of amplitude andfringe (delay,delay-rate, andphase) calibration. The user would receive a complete, calibrated dataset suitablefor imagingand self-calibration. An additional service providing the actualimaging is alsoavailable onrequest; since the method of imaging may depend quite strongly on thescientificgoals of aparticular project, this service will be negotiated on a case-by-casebasis.
Initially, these new services are being offered on a trial basis forone year,and are restricted torelatively straightforward projects until more experience is gained inbalancing theneeds of theusers with the load on NRAO staff. The eligible projects will becontinuumobservationsincluding no more than ten source-frequency combinations in thefrequency rangebetween 1.4and 15 GHz. The services may also be requested for observations at 22GHz; theserequests willbe filled if the demand and the staff load permit.
Calibration and/or imaging services can be requested at the time ofproposalsubmission,preferably by checking the appropriate box on the new proposal coversheet(available athttp://info.cv.nrao.edu/html/headquarters/vlba-gvlbi.html), by making a requestdirectly in thebody of the proposal, or by direct request to Jim Ulvestad atjulvesta@nrao.edu.
J. S. Ulvestad
VLBI Network CallForProposals
Proposals for VLBI Global Network observing are handled by the NRAO.There usuallyare fourGlobal Network sessions per year, with up to three weeks allowed persession. TheGlobalNetwork sessions currently planned are:| Date | Bands | ProposalsDue |
| 09 Sep to 30 Sep 1999 | 6 cm, 5 cm?, 18 cm, UHF | 01 Feb 1999 |
| 12 Nov to 03 Dec1999 | 6 cm?, 5 cm?, 18 cm, 1.3cm | 01 Jun 1999 |
| 10 Feb to 02 Mar 2000 | 6 cm, 18 cm, other? | 01 Oct 1999 |
| 25 May to 15 Jun 2000 | 6 cm, 18 cm, other? | 01 Feb 1999 |
10 Slot Mailbox Near Me Location
The bands above marked with a question mark have been suggested, butthe finalchoice has notyet been made.
It is recommended that proposers use a standard cover sheet for theirVLBIproposals. Fill-in-the-blanks TeX files are available by anonymous ftp fromftp.cv.nrao.edu,directoryproposal or via the VLBA home page on the web. Printed forms, forfilling in bytypewriter, areavailable on request from Lori Appel, AOC, Socorro.
Any proposal requesting NRAO antennas and antennas from two or moreinstitutionsin theEuropean VLBI network constitutes a Global proposal. Global proposalsMUST reachBOTHNetwork Schedulers on or before the proposal deadline date; allowsufficient timefor mailing. Ingeneral, fax submissions of Global proposals will not be accepted. TheSocorrocorrelator will beused for some EVN only observations unsuitable for the Bonn correlatoruntil suchtime that theycan be processed with the JIVE correlator. Other proposals, not in EVNsessions,requesting useof the Socorro correlator must be sent to NRAO even if they do notrequest the useof NRAOantennas; proposals for the use of the Bonn correlator must be sent tothe MPIfR ifthey do notrequest the use of any EVN antennas.
For Global proposals, or those to the EVN alone, send proposals to:
For proposals to the VLBA, or Global Network proposals, sendproposals to:
Proposals may also be submitted electronically, in Adobe Postscriptformat, toproposevn@hp.mpifr-bonn.mpg.de or propsoc@nrao.edu, respectively. Careshould betaken toensure that the Postscript files request the proper paper size.
B. G. Clark
Dynamic Scheduling
If you have looked at VLBA schedules recently, and wonder why theycontain so muchwhitespace, without scheduled projects, it is because these spaces are beingfilledshortly beforehandfrom a list of projects approved for dynamic scheduling. This queue wasfilled with46 proposalssubmitted for the 1 October 1998 proposal deadline and an additional 17weresubmitted for the1 February 1999 proposal deadline. The queue was first used in lateFebruary tofill in timeoriginally scheduled for HALCA observations canceled due to problemswith thespacecraft. Through the end of May, 45 segments of 28 proposals were scheduleddynamically.
Currently, ittakes too much time to prepare a dynamically scheduled program forobserving to takeaccount ofthe weather. However, it has been used successfully to avoid observingwhen arequired receiveris inoperative. Streamlining the system to permit choosing the projectto be runimmediatelybefore the observation starts is currently underway.
Observe files for dynamically scheduledprojects are written in LST for the Pie Town antenna (chosen asapproximately thecenter of thearray), so they can be easily relocated in UT. The dynamic scheduleprocess startswhenobservers send their observe files to 'vlbiobs.' These are thenchecked by thetechnical contactfor the project, and then entered into the queue. The currentcontents of thequeue may be foundthrough the VLBA schedule web pages, at http://www.nrao.edu/vlba/schedules/dynqueue.html. Since a dynamically scheduled observe file must make its way throughseveral hands,it is a goodidea for observers to check to ensure that their project has indeed madeit into thequeue. Since itsometimes takes more than a week for an observe file to get through thisprocess,observersshould prepare their observe files as soon as possible, and not expectfiles to beobserved as soonas received.
Once in the queue, proposals remain there until they are observed (seedyndone.html)or until they have been there about a year (we shall notify the contactperson ofanysuperannuated proposal removed from the queue). In order to increasethe likelihoodof beingscheduled, proposers may specify that the observation could be made withone or moremissingantennas, or that time could be trimmed from the ends of allocatedslots. This maybe done at anytime, before or after the proposal is inserted into the queue, by emailtobclark@aoc.nrao.edu.
B. G. Clark
The VLBA at theAAS
10 Slot Mailbox Near Me Yellow Pages
The NRAO hosted a topical session entitled 'High Angular ResolutionScience with the NRAOVery Long Baseline Array' at the Centennial Meeting (30 May - 3 June1999) of theAmericanAstronomical Society in Chicago. This event included an all-day seriesof oralpapers, a postersession, a press reception, press conference, and a VLBA-specificpromotionaldisplay.
Throughout the AAS meeting, a specially-prepared NRAO display on theexhibitfloorshowcasedsome highlights of research done with the VLBA in its first five yearsof fulloperation. Thedisplay also emphasized the capabilities of the VLBA, as a reminder tousers andhopefully as anenticement to astronomers who have not yet used the VLBA. NRAOannounced newservices fornovice U.S. users at this meeting, and a handout provided at the displayoutlinedthose services.(See article by J. Ulvestad).
On Monday evening (May 31), AUI hosted a verysuccessfulreception for the press, in which NRAO scientists and our invitedspeakers for thetopical sessionmet with science journalists covering the meeting. Tuesday, June 1, sawa postersession thatpresented many exciting research results from the VLBA. The discussionsaround theposterswere animated and drew many visitors and interested, non-expert VLBIusers.
With so many excellent research results presented at the two VLBAsessions, NRAOhosted a press conference to highlight some of those results as well asto reviewthe VLBA's major research accomplishments over the past several years.The geometricmeasurement of the distance to NGC 4258 by J. Herrnstein et al.,received themost press coverage, with storiesappearing in the NewYork Times and numerous other newspapers through wire reports by theAssociatedPress andReuters. The story also appeared on numerous web news sites, includingCNN andABC.
Nearly100 science journalists from around the world attended the AAS meeting.The pressconference,and the press releases about radio astronomy research distributed byNRAO and otherinstitutions,showed these reporters the wide range of contributions made by the VLBAand otherradiotelescopes to the progress of astrophysics.
On Wednesday, June 2, the oralpresentationshighlighted the work of eight VLBA users, including that of two graduatestudentsand twopostdoctoral fellows. The presenters were J. R. Herrnstein (NRAO), A.P. Marscher(BU), K.Blundell (Oxford), C. G. Mundell (UMd), N. Bartel (York U.), M. D.Faison (U.Wisconsin), W.F. Brisken (Princeton), and P. J. Diamond (Univ. Manchester).Thepresentations covered a widerange of topics, from pulsar distances to radio-quiet quasars. Twoadditionalpresentations weremade by J. Ulvestad and J. Wrobel on the capabilities and the use of theVLBA.During the day,more than 100 people were in attendance at the presentations.
In all, we felt theeffort toshowcase the science of the VLBA and present its capabilities and usageto our AAScolleagueswas quite successful; ongoing activities of this kind for the VLBA andallinstruments of theNRAO will continue this effort.
M. J. Claussen and D. G. Finley
12 METER
Major Summer Shutdown Projects at the 12Meter
The 12 Meter Telescope will be shutdown for approximately six weeksstarting onJune28th. Wewill follow this with an approximately three-week period of system testsbeforeresuming regularobserving. During these periods we will do a number of repair,maintenance, andupgrade tasks,which include:
- Replace the dome cover,
- Install a new prime focus control system,
- Improve diagnostic routines and reliability of the MAC,
- Do maintenance on the central cold load calibration system,
- Improve the receiver and IF system to increase continuumsensitivity.
Notethat we are shutting the telescope down one week earlier than usual thisyear toaccommodate thedome cover replacement project.
J. G. Mangum & T. W. Folkers
Symposium on Imaging at Radio throughSubmillimeterWavelengths
A symposium on 'Imaging at Radio through Submillimeter Wavelengths'was held atthe Ventana Canyon Resort in Tucson on June 6-9, 1999. This symposiumbroughttogether scientists and engineers working in the rapidly developingfield ofastronomical imaging at radio through submillimeter wavelengths. Topicsincluded:
Algorithms for processing interferometric multi-field images. Approximately 125 scientists re resenting research institutes from atleast 14different countries attended'Imaging99'. A total of49 invited and contributed oral presentations combined with 41 postercontributionsoffered aplethora of scientific and technological developments. The proceedingsfrom thisconference willbe published in the Astronomical Society of the Pacific (ASP) ConferenceSeries.
J. G. Mangum
IN GENERAL
AIPS++ Release
We expect to release version 1.0 of AIPS++ on CDROM inSeptemberfollowing a final round ofin-house and beta testing. The CDROM will contain installations forLinux (Red Hat5.1, 5.2 and6.0, SuSE 6.0), and Solaris (2.5.2 and 2.6). AIPS++ can be run from theCD, but forbetterperformance an installation to disk is recommended. Installation is veryeasy andrequires nospecial system privileges.
If you would like to receive a copy of the CDROM, please emailaips2-request@nrao.edu with your name, email, and shipping address.There is nocharge.
The capabilities of the package as released can be toured from theAIPS++ homepage at http://aips2.nrao.edu. Inbrief, thepackagecontains tools for:
Extensive and powerful scripting capabilities are available via theGlish commandlanguage. Commands may be entered both from the command line and fromgraphical userinterfaces. Documentation and support are bothavailable on-line.
A second release is planned for early 2000. This next version isexpected toinclude support for VLBI processing, single dish On-The-Fly processing,moreadvanced interactive dataediting andvisualization.
T. J. Cornwell
Observatory-WideComputingDevelopments
Security - Computer and network security continuesto be a majorconcern at the Observatory.The NRAO's computer security practices must balance the need forreasonable accessby users toour computing services from outside the Observatory with the need toprotect thoseservicesfrom willful damage by unauthorized users. In recent months, we haveseen aconsiderableincrease in the 'probing' of computers and networks from outside theNRAO. Theseprobes are often used to detect vulnerabilities in our systems' configuration.There have alsobeen a fewbreak-ins which briefly disrupted some of the services we provide tonon-NRAO sitesand hadthe potential for greater damage.
The Computing Council and a group of NRAOtechnical staffare studying ways to improve the security of the computers andnetworking withoutcompromising any services that are fundamental to our role as a userfacility. It islikely that somechanges may be required in the ways that users at other locationsconnect to NRAOsystems.Because many network services contain security holes which cannotalways be easilyfixed, anyto which access from outside of the NRAO is not essential may in futurebe blocked,to reduceour vulnerability.
Every effort will be made to identify the impact of new securitymeasures, andto notify users they may affect, before changes are implemented.
To reduce therisks associatedwith remote access, we strongly recommend, and may eventually require,the use ofthe secureshell ('ssh') package to replace the more common 'telnet', 'rlogin',and 'rsh'connectionsbetween the NRAO and your home system. ssh encrypts the transmitteddata, includingyourpassword, and thus hides account information from 'sniffer' programs.ssh issupported at allNRAO sites. Software to make ssh connections is available for UNIX andWindows, inboth freeand commercial versions. We urge all NRAO users to install ssh on thecomputersthat they willuse to connect to our systems.
Computing Facilities - Budget limitations havereduced thenumber of workstation upgrades thatwe can do this year. This also applies to facilities for visitingobservers. Weexpect to upgradeone high-end visitor workstation in Charlottesville and five oldersystems in thevisitors' areas atGreen Bank, but upgrades of the online system at the VLA and of datastoragecapabilities at the12 Meter were given higher priority at the AOC and Tucson. Sincemost of ourexisting publicworkstations will be three years old at the end of 1999, we plan to doadditionalupgrades at allsites next year.
Networking - As described in the previous NRAONewsletter, theNRAO recently received anNSF grant to upgrade our internal network. This grant will allow us toimproveinter-site dataexchange capabilities, and to support video- andwhose systemdateshave been advanced beyond the century rollover are being used forstand-alone testsof anysoftware packages for which significant concerns remain.
Like many organizations,the NRAO'sY2K readiness also depends on that of outside providers of supplies andservices.Again like manyorganizations, we are finding that firm assurances from third partiesabout Y2Kreadiness are hardto come by, so some Y2K contingency plans are being made.
M. R. Milner
Charlottesville ComputingDevelopment
Linux News - One of the two remaining IBM RS/6000AIX systems atNRAO has been recentlydecommissioned; it was replaced by a public Linux Intel system with dualprocessors,twice thememory, and more disk space (for a very small fraction of the cost ofthe RS/6000!).Judging bythe popularity of the machine with local staff and visitors, theimprovement hasbeen muchappreciated.
As the deployment of Linux/Intel systems throughout the observatorybecomes morecommonplace, it is important for NRAO to keep sensibly up to date withreleases ofthe kerneland the operating system. To that end, staff in Charlottesville havetested the new2.2 kernel,which allowed us to make early use of symmetric multi-processing andalso the muchdesired NFSfile locking. Initial results with this new kernel are veryencouraging, and astandard NRAOLinux distribution based on it is currently being tested and deployed.
A new record AIPSMark was set for Intel systems with thisdistribution. APentium III 500 MHz system with 256Megabytes of memory and a 7200 RPM EIDE disk (tuned) was used with the15APR99versionof AIPS; the result was an impressive 17.9 AIPSMarks. This is stillshort of theabsolute record(24.6, for a HP system); details as usual are in the benchmarkingsection of theAIPS web page athttp://www.cv.nrao.edu/aips/.
The Year 2000 (Y2K) - In addition to the Y2K issuesmentioned inthe section onObservatory-wide Computing, progress has been made in Charlottesville onseveralfronts. At thetime of writing, we have almost completed upgrading our Suns to a Y2Kcompliantoperatingsystem version. In addition, we have established a Y2K 'war room' withseveralmachines whosedate has been advanced to beyond January 1, 2000. One of these machines(Linux) hasbeenoperating for several months already without a hitch (and hassuccessfully run AIPS,includingdata transfer via FITS files to systems operating in 'normal' time). Asparcstationand a WintelPC are to be added to this list. These machines are intended for localstaff to testout programs orpackages of concern to them.
P. P. Murphy
Frank Drake to Give JanskyLecture
The 1999 Jansky Lecture, 'Progress in the Search for ExtraterrestrialIntelligence,'will be givenby Dr. Frank Drake, currently a Research Professor at the University ofCalifornia,Santa Cruzand President of the SETI Institute in Mountain View, California.
Frank Drake was one of the earliest U.S. trained radio astronomersand one of thefirst members of the NRAO scientific staff. While living in Green Bank40 years ago,Drake used the 85 Foot Tatel Telescope andthe 300Foot Telescope to study the nature of planetary surfaces andatmospheres. Togetherwith HeinHvatum, he discovered the non thermal radiation from Jupiter's Van AllenBelts.Following abrief period at JPL, he became Director of the Arecibo Observatory wheretheinitiated the earlypulsar observations there. Before leaving Arecibo to become Dean ofScience at theUniversity ofCalifornia in Santa Cruz, he was a strong proponent for the constructionof aGregoriansubreflector to correct for the spherical aberration which ultimatelylead to therecent majorupgrade of that telescope.
Dr. Drake is well known for his work on the search forintelligent life inthe universe. His Green Bank Project Ozma was the first serious attemptto detectextraterrestrial intelligence. His formulation of the number of intelligentcivilizations in the galaxy,which has become known as the 'Drake Equation,' has been the guidingprinciplebehind allsearches for radio signals from extra terrestrial civilizations.
Dr. Drake will present the Jansky Lecture in Charlottesville onOctober 26, inGreen Bank on October 27, in Tucson on October 29, and in Socorro onOctober 30. TheAnnual NRAO-UVA Internal Symposium will beheld inCharlottesville on October 26, while the annual New MexicoSymposium will beheld in Socorroon October 30.
K. I. Kellermann
NRAO Real-TimeComputingMeeting
A meeting on real-time computing systems at the NRAO was held at theAOC inSocorroand atthe VLA Site from April 12-14, 1999. The meeting principallyconsisted ofreports from NRAOsoftware developers and hardware engineers, with additionalcontributions fromnon-NRAOscientists and engineers. This meeting, the first of its kind in morethan tenyears, was particularlytimely as the observatory plans for its software contribution to theALMA project,and preparesitself for the VLA expansion. The meeting was a success, and it is hopedthatsimilar meetings canbe held in the future. The agenda and some of the papers presented atthe meetingare available athttp://www.nrao.edu/Real_Time/
B.E. Glendenning