1983AJ. oo oo 00 O'! b) a) 439 Astron.J.88(3),March1983 first partofanefforttoprovideUBVRIphotoelectric photometric standardstarsinthemagnituderange fied andextendedbyCousins(1976). though, werelocatedatshorterwavelengths:R observations publishedbyKron,White,andGascoigne ences therein).AnotherRIsystemhadbeendefinedvia son, Mitchell,Iriarte,andWisniewski1966,refer- hence wereavailabletoastronomersinbothhemi- These stars,designedtobeusedasstandards,werelo- Science Foundation. VisitingAstronomer,1977-1981, at CerroTololoInter-American on thecelestialequator,andthereforeareeasilyaccessi- stars thatwereobservedarelocatedinabandcentered 1 astronomers obtainatthetelescope.Themostusedpho- for thecalibrationofintensityandcolordatathat ble standardstarphotometricsequencesarenecessary 174. THE ASTRONOMICALJOURNAL The photometricresultsinthispaperrepresentthe The UBVphotometricsystemhasbeenexpandedto Accurate, internallyconsistent,andreadilyaccessi- © American Astronomical Society • Provided by the NASA Astrophysics Data System 8 UBVRI PHOTOMETRICSTANDARDSTARSAROUNDTHECELESTIALEQUATOR' paper fallintherange1SVS12.5and—0.35(5V)S+2.0. new UBVRIstandardstars,availabletotelescopesofavarietysizesinbothhemispheres,on degree bandcenteredonthecelestialequator.Theobservingprogramwasplannedtoprovide Areas 92-115.Thestarsaverage20.7measureseachon12.2differentnights.inthis an internallyconsistenthomogeneoussystemaroundthesky.MostofstarsareinSelected UBVRI photoelectricobservationshavebeenmadeof223starsmostlyinanapproximatetwo II. THEPROGRAM I. INTRODUCTION LSU Observatory,BatonRouge,Louisiana70803 0004-6256/83/030439-22$00.90 b) ARLOU. LANDOLT Received 8November1982 VOLUME 88,NUMBER3 ABSTRACT bright forthe0.4-mtelescopeRCA31034pulsecount- on magnetictapeandhencewere easilytransferablefor to guestobserversatCTIOwereoperatedvoltages an RCA31034typephotomultiplierusedinapulse ric. 0.4-m telescopewerethentobeusedasstandardstarsat versity SystemNetworkComputer Center. via anIBM3033computerat theLouisianaStateUni- final reduction.Alldatareductions wereaccomplished ing. Dataobtainedatthe0.9-m telescopewererecorded computer programwhichsubsequentlydidtheprocess- tape. Thedatawereaveragedbyhandandenteredintoa obtained atthe0.4-mtelescopewereprintedonpaper recommended bytheCTIOoperationsstaff.Thedata counting mode.Thevariousphotomultipliersavailable time assignedtothispartoftheprojectwasphotomet- equipment stability.Sixty-sixpercentofthetelescope tional nightsonthesetwotelescopeswereusedtocheck the 0.9-mtelescope,andsoon,usinglargertelescopesat ing combination.Starsmadeintostandardstarsviathe ble totelescopesofallsizesinbothhemispheres.The shown elsewhere(Landolt1983,inpreparation),addi- scope nightsandon410.9-mtelescopenights.Aswillbe data wereobtainedforthisprogramon530.4-mtele- ments. lessen demandfortelescopetimeonthelargerinstru- each stepoftheprocess.Suchbootstrappingalsowould color wereunobservablebecausetheyjusttoo scope. Eventhen,severalofthestarsmoreextreme manufacture ofnewstandardstarsatthe0.4-mtele- mostly V<1.0.Therefore,itwasnecessarytobeginthe strapping theme.TheCousins(1976)R/standardstars observational dataweretiedintotheUBVstandard available atthetimethatprojectbeganwerebright, stars ofLandolt(1973)andtheRIstandardsCousins (CTIO) 0.4-mand0.9-mtelescopeswerescheduledfor (1976). 89 and91nights,respectively,intheintervalSeptember 1977 throughOctober1981.Acceptablephotometric All ofthephotometricobservationsweremadewith The CerroTololoInter-AmericanObservatory The observingplanbynecessityfocusedonaboot- © 1983Am.Astron.Soc.439 MARCH 1983 1983AJ. oo oo 00 O'! 440 A.U.LANDOLT:UBVRIPHOTOMETRICSTANDARDS provement intheaccuracyoffinalresults. both atmosphericandinstrumentalconditions.Proofof the needforthiskindofcorrectionisshownbyim- made toallprogramstarmeasures.Thecorrectionsnor- Such correctionstookintoaccountsmallchangesin mally werelessthanafewhundredthsofmagnitude. night. Theseplotspermittedsmallcorrectionstobe each standardstaragainstUniversalTimeforagiven month intervalduringwhichthesedatawereobtained the averageextinctioncoefficientsfoundoverfifty- coefficients forthesamedata.Asapointofinformation, than wereobtainedthroughtheuseofmeanextinction project afterfindingoverallresultswithsmallererrors whenever possible.Thistechniquewasadoptedforthis ing extinctioncoefficientsderivedfromthatnight possible. Ingeneral,thestandardstarswereobserved als intheVmagnitudeanddifferentcolorindicesfor standard stars.Hence,itwaspossibletoplottheresidu- clock inthe0.9-mtelescopedome.Onepieceofinforma- clock inthe0.4-mtelescopedomeorviacomputer are presentedinTableI. tions wereobtainedatlessthan1.5airmasses. stars. Thevastmajorityoftheprogramstarobserva- over anairmassrangeatleastasgreattheprogram each groupcontainingstarsinaswideacolorrange They wereobservedingroupsofatleastthreetofour, magnitude andcolorindiceresidualsforeachofthe tion includedonthefinalcomputerprintoutwas tion information.Agivennight’sdatawerereducedus- the preceptsoutlinedbySchulteandCrawford(1961). tered. Thereductionoftheobservationaldatafollowed ly provedsufficientforthemagnituderangeencoun- most occasions.Ten-secondcountingintervalsnormal- measures. A27-secondofarcdiaphragmwasusedon stars wereobservedperiodicallythroughoutthenight. night alongwiththeprogramstars.UBVRIstandard color indexsymbolvalue lists (1973,1976)intheE-regionswereobservedeach Magnitude orCoefficient VBURIIRUBV starplusskyfollowedbyVBURI B —Vk+0.111 R —Ik + 0.046 U-B k+0.318 l V-I k +0.087 7 V— Rk+0.042 3 9 5 All observationaldataweretimedviaanAccutron The standardstarsalsowereusedtoprovideextinc- The datawereobtainedinaseriesofmeasures Some 15to25standardstarschosenfromCousins’ © American Astronomical Society • Provided by the NASA Astrophysics Data System V Q+0.172 y Table I.AverageCTIOextinctioncoefficients. a) The0.4-mTelescopeObservations k -0.020 k 0.0 k 0.0 k -0.026 k 0.0 4 s 6 2 i0 junction withtheRCA31034photomultiplier.The the temperatureleveltowhichphotomultiplieris determine thebestfiltercombinationtobeusedincon- Graham oftheCTIOstaffduring1977andearly1978to dard stars.Themagnitudeandcolorindicesdiffered Table III.Thesefilterswereusedfortheremainderof to matchfiltersascloselycircumstancesallow, transformation relations.Anobserver,therefore,needs cooled (Bessel1979,AppendixI)hasaneffectuponthe lished byBessell(1976,1979).Hisworkshowsthateven try. Sincethen,asimilarextensivestudyhasbeenpub- photometric systemaswelltheCousinsR/photome- goal, ofcourse,wastomatchasbestonecould,theUBV system definedbyCousins’(1973,1976)E-regionstan- mission characteristics. the program.Graham’s(1982)Fig.1showstheirtrans- ham’s efforts,aswitchwasmadetothefiltersgivenin ice) toensurethebestpossibletransformation. cool tosome“standardstable”temperature(usuallydry should usethesametypephotomultiplier,and slightly forthestarsobservedinSeptember1977,Jan- constancy ofthestarsbothinbrightnessandcolor. acteristics wereaknownquantity,andtheirvalueas from thosepublishedearlier(Landolt1973).Theirchar- were chosenfromtwosources.First,starstaken tions listedinTableII.Atthatpoint,followingGra- uary 1978,andAprilsawuseofthefiltercombina- the resultshavingbeentiedintoan£/i?FR/photometric ascension. Thedatawerereducednightbywith celestial equator,anddistributedaroundtheskyinright search tolocatequiteblueandredstars. published earlierwasashortageofstarsreallybroad tion, furtherUBVmeasureswoulddoublecheckthe indices tothealreadyknownC/2?Finfbrmation.Inaddi- standard starscouldbeenhancedbyaddingRIcolor telescope, moststarsfallingwithinadegreeortwoofthe range incolor,anattemptwasmadeviaaliterature Second, sinceashortcomingofthosestandardstars R 4mmSchottKG1+2OG51.5RG6 B Corning5030+GG385 / 3mmSchottRG715+1780 I 3mmRG715+1 RG 780 B 2mmGG385+ BG 18+2mm12 R 2mmKG3+OG 570 U Corning9863+solidCuS0crystal V Corning3384+9780 U Corning9863+solidCu S0crystal An extensiveeffortwasundertakenbyDr.JohnA. V 2mmGG495+ BG 18 The programstarsobservedatthe0.4-mtelescope The firstthreeobservingruns,September1977,Jan- 4 A totalof147starsmadeuptheprogramat0.4-m 4 Table II.Filtersusedearlyinprogram. Table III.(72?glassfilters. 440 1983AJ. oo oo CO (S\ the UBVstandardstarsavailable(Landolt1973).The slope was0.76%,andtheaveragezeropoint steps described,usingthefiltersinTableIII,accom- ences ofnomorethan0.0117magnitudes.Theaverage had slopesofnomorethan1.48%,orzeropointdiffer- son oftheC/2?Fresultswithpreviouslypublishedvalues plished thegoalforR/indices.However,acompari- tion ofalldataintoonelargeset.Theserelations these relationstaketheform,utilizing63starsinLan- a givenstarminustheequatorialstandardvaluesfor up tothispointherein,whichwerebasedonCousins showed smalldifferencesbetweenUBVvaluesderived were derivedwhichpermittedthesuccessfulcombina- dolt (1973)havingfiveormoremeasureseach: the samestarsgivenbyLandolt(1973).Mathematically, quantities tiedintoCousins’E-regionstandardstarsfor the April1978observingrun.Transformationrelations uary 1978,andApril1978duetothefilterchangeafter (Landolt 1973).Thedeltaquantitiescalculatedwerethe (1973) UBVstandardstars,andmypublishedvalues sins’ (1973)UBVsystemandmyequatorial(Landolt have shownAV=-0.00027+0.00917,A(B—V) sion lines,straightdifferencesinthesamesensewould 441 A.U.LANDOLT:UBVRIPHOTOMETRICSTANDARDS star’s {B—V)colorindex. standard starsasafunctionofLandolt’s (1973)equatorialstandard Fig. 1.AcomparisonoftheVmagnitude tiedintoCousins’E-region 1973) Í72ÍFsystemthenwereapplied.Thesuccessofthe — 0.0050magnitude. + 0.02191. = +0.004940.01213,axiàA(U—B)=+0.00457 A goaloftheprojectwastoaddCousins’Æ7indices [B —V)=+0.008550.98163(2?-F) These slightcolorequationdifferencesbetweenCou- (U-B)= -0.01685+1.02458(C/-2?) © American Astronomical Society • Provided by the NASA Astrophysics Data System If onehadnotintercomparedthedatausingregres- Cousins ^ ^Cousins"f"0.00341—0.00431(2?F) Cousins Cousins ± 0.002030.00233, ± 0.002420.00299, + 0.00215+0.00249. the quantitiesobtainedwithRCA31034afterremo- obtained forthesamestargivenbyLandolt(1973)equa- ta quantitiesplottedontheordinateineachfigureare operation isillustratedgraphicallyinFigs.1-3.Thedel- tied thoroughlyintotheUBVsystem(Landolt1973). being giventotheblueststars.Twelvenightswerespent photomultiplier, andIwasnotcertainhowdatafromit dolt (1973)andtheRIdataweretiedintoCousins Landolt (1973).TheUBVdatathenweretiedintoLan- torial standardstars.Theabscissavaluescamefrom val ofthetransformationnonlinearityminusvalues on thisaspectoftheprogram.Theresultingdatawere would transferontoan£/2?Fsystembasedupona1P21, (1976). dard star’s(U—B)colorindex. Stars ofallcolorswereobserved,withspecialattention CTIO 0.4-mtelescopeusinga1P21photomultiplier. region standardstarsasafunctionof Landolt’s(1973)equatorialstan- Fig. 3.Acomparisonofthe(U—B) colorindextiedintoCousins’E- I measuredasubsetofthe147programstarsat standard star’s(B—V)colorindex. Fig. 2.Acomparisonofthe(B—V)colorindextiedintoCousins’ E-region standardstarsasafunctionofLandolt’s(1973)equatorial W Zh °' 0. o o. > (0 0) I -°- Since thiswasmyfirstexperiencewithanRCA31034 -0. -0. -0. 0. o. CB-V) 441 1983AJ. oo oo CO (S\ 442 A.U.LANDOLT:UBVRIPHOTOMETRICSTANDARDS RCA 31034asafunctionofthe(B-V)colorindexobservedwith Fig. 4.Acomparisonofthe{B—V)colorindexobtainedwith each. Landolt (1973);opencirclesareforstarswithlessthanfivemeasures the quantitiesobtainedwithRCA31034minus delta quantitiesplottedontheordinateineachfigureare linear. ThesituationisillustratedinFigs.4and5. that the(B—V)and[UB)transformationswerenon- from theRCA31034,usingstarsincommon,showed dent uponinspectionofFigs.4and5,thatlinearrela- values obtainedforthesamestarwitha1P21.Itisevi- 1P21. Closedcirclesindicatestarswithfiveormoremeasureseachin tions wouldintersectat+0.1and—0.2for[BV) and {U—B\respectively.Graham(1982)hadfound nonlinear relationsseemtobebettertakenintoaccount equipment, Itestedbothpossibilities.Formydata,the that thelinearrelationsmetinregion (B —V)~{UB)b0.4.Sinceweusedthesame RCA 31034asafunctionofthe(£/ — 2?)colorindexobservedwitha Fig. 5.Acomparisonofthe(t/—i? )colorindexobtainedwiththe 1P21. Thesymbolshavethesamemeaning asinFig.4. Comparison ofthe1P21resultswiththosederived © American Astronomical Society • Provided by the NASA Astrophysics Data System the relations: observed (B—V)and(UB)valueswerebluerthan at [B—V)=+0.1and[U—B)=0.2.Starswhose the RCA31034photomultiplier,andinitiallytiedinto al (1953). was deemeddesirablesincethevastmajorityofUBV Cousins’ (1973)E-regionstandardstarsarenowonthe easily comparable.And,thefinalRIvaluesareonCou- stars. Therefore,pastandfutureresultsshouldbemore photometry inrecentyearsusedLandolt’sstandard sins’ (1976)system,descendedfromtheworkofKronet be appliedtothosedataobtainedin1977andearly1978 0.4-m telescope.Thestandardstarsusedwerethose observations. TheprogramstarscamefromTablesI seconds ofarcwasusedtoobtainthemajority manufactured atthe0.4-mtelescope.Adiaphragm16 ployed atthe0.9-mtelescopemimicedthoseused to transferthosedataontothephotometricsystemde- and IIinLandolt(1973).Againsmallcorrectionshadto The situationisillustratedinFigs.6and7.delta 0.9-m telescoperesultsandtheLandolt(1973)values. fined bythefiltersinTableIII.Oncedone,acompari- five ormorepublishedmeasures,wasmadebetweenthe son, whichused67starsfromLandolt(1973),eachwith UBV systemdefinedbyLandolt(1973).Thisexercise + 0.1and—0.2,respectively,thenwerecorrectedby Fig. 4. star’s [B—V)colorindex.Thesymbols havethesamemeaningasin RCA 31034asafunctionofLandolt’s (1973)equatorialstandard Fig. 6.Acomparisonofthe{B—V) colorindexobservedwiththe The UBVportionoftheUBVRIdatacollectedwith [JJ B»corrected=~0.01317+0.94118(i/-2?) [B -F)=0.00765+1.04851(2?V) The dataacquisitionandreductiontechniquesem- corrected b) The0.9-mTelescopeObservations + 0.002170.01729, + 0.014340.01856. 442 1983AJ. oo oo CO (S\ r 443 A.U.LANDOLT:UBVRIPHOTOMETRICSTANDARDS for thatsamestargivenbyLandolt(1973).Thesedelta the RCA31034dataandpublished1P21values. for nonlinearityofthetransformationrelationsbetween equatorial standardstars.Onceagainthereisevidence quantities thenwereplottedasafunctionofeitherthe quantities ontheordinateineachfigurearecolor lations, then,wereeffectedviatheequations: peared at(B—V)b0.1and{UB)0.2Cor- Again, upontesting,thenonlinearbreakpointsap- [B —V)or(U5)colorindexgivenbyLandolt’s(1973) the correspondingequatorialstandardstarcolorindices indices obtainedwiththeRCA31034forastarminus rections demandedbythenonlineartransformationre- pared toLandolt’s(1973)results onceagain.Thesuccess ( ^B)corrected ( ^B)corrected star’s [U—B)colorindex.Thesymbolshavethesamemeaningasin Fig. 7.Acomparisonofthe(C/—B)colorindexobservedwith Fig. 4. RCA 31034asafunctionofLandolt’s(1973)equatorialstandard V = corrected © American Astronomical Society • Provided by the NASA Astrophysics Data System The correctedmagnitudeand colorindiceswerecom- V-0.00189 -0.00068(i? F) — 0.00406+1.06740(£V)(BV)<+0.1 + 0.006970.00757 — 0.03066+0.89818(6/B){U-B)<-0.: + 0.00240±0.00253 + 0.01037+0.98992(Æ-V)(Æ-F)>+0.1 ± 0.003310.02140 ± 0.001710.00200. + 0.003470.00395 — 0.02382+1.01895(6/B)(U-B)> corrected ^ )corrected ^ Icorrected index. function ofLandolt’s(1973)equatorial standardstar’s(U—B)color by Landolt(1973)equatorialstandardstars.Theabscis- RCA 31034afterremovalofthetransformation nonlinearityasa Fig. 9.Acomparisonofthe(U—B) colorindexobservedwiththe in thesenseRCA31034valuesminusLandolt(1973) values: AV=-0.00121+0.00941;A(B-V) 67 starswithatleastfivemeasureseachinLandolt sa valuescamefromLandolt(1973). earity minusthevaluesobtainedforsamestargiven RCA 31034afterremovalofthetransformationnonlin- nate ineachfigurearethequantitiesobtainedwith in effectingthenonlineartransformationsisshown (1973) withthenew0.9-mdatainthispapernowshow, Figs. 8and9.Thedeltaquantitiesplottedontheordi- index. function ofLandolt’s(1973)equatorialstandardstar’s[B—V)color Fig. 8.Acomparisonofthe[B—V)colorindexobservedwith RCA 31034afterremovalofthetransformationnonlinearityasa + 0.01857.Hence,thedataobtainedat0.9-mtele- = —0.00022+0.00869;and^l(UB)-0.00035 A comparisonofthemagnitudeandcolorindicesfor 443 444 © American Astronomical Society A. U.LANDÖLT:UBVRIPHOTOMETRICSTANDARDS

Table IV. UB VRI standard stars. o 00 in in —inroitroAiA4oin AJCO —AJO'vOAI'OOin rvA4incoocOititro(> oooooooooo A-O'oO'ooinovDinro ovDoooinAiininit ro<>(>ooin —vovoinco ovo-ooitAiininit v0A4Or^OvDA-AIOit o —ovDitoorocoinro fOOOOOOA-OAIAICOAl oooooooooo oooooooooo inAiin^tA4v£>A4roinoo in —OitininooooA ChovOAiro-ititinA' itinrocoininA40Ai — — ro•oinooo* — (>00-ititoino oooooooooo oooooooooo oooooooooo ooitincovoco^inin=t invDA'O^rom —ooin^t oooooooooo oooooooooo ro oo—roaiin — O'rovoroit'X>ooo itvDOOAO'it —cooro OvD —inOvOvOit vDitvOitA- —inT0A4 initoooot^O'itxviA' oooooooooo oooooooooo r^oo^3-inAiA4Aicom OvDAIOitAjfnA'OOin oooooooooo o —mnaionA4ovDoovf itrOOOA- OvOAOO 0 —oooooo — PO-A400'it0000 itAiO'O'cocoroitAin ititcoro —coocoo'it ifAIOOitct -—A4AJAJAlinAIAJv£) oooooooooo OOOOOOOOO oooooooooo oooooooooo monooocnifCN —m in —itooAiinoaii'' oooooooooo oooooooooo oooooooooo vü aioo^npoon IP —^Alf''ÍN 1 +I Aj in •in —oooo- in A4— — O' I • 00—O'A4- 1 roAjroroititititit'O — 00O0^v0ino om<>rorovoororo[^ oooooooooo inO^itA' —AJAirOOvD oininininininininin itOvDOOOOOOA o —inroitroitroinro O'OOOOOAlin —AJAJvO — initroititAjo inOAJvOOOOOOOO' — vD —OO'itOOO'rOitAJ t^in —inroAiroA4itco oor^inroo'ititininit oooooooooo oooooooooo ai —oininvocoooin vdooooaioo —inin Oit —OCOAIOCAit A4 —roitOitOit oooooooooo mitooAj^-in^invDC> oooooooooo — oAiroroitAioo — rovOAvDA4roitro A4 —oititinoooooin roo —ooin-Aiinoo O' —OOOOititO'OO — inOA4AIA4ititinOO it —OOvOOAJinOit — ooitoinoroito oooooooooo oooooooooo oooooooooo oooooooooo ooOitininAOitvo — vDrOOitvOOOOOAIO' — inOA4A4rOititUOA' oooooooooo AJCOAIAirOfOAJAIfOin o —AiAjminc>ovDin oooooooooo — inAO'O'vOOOAl OOCOOO —OOAJAlvDCA oooooooooo oooooooooo — A|AlitAIAIit OOCNIOO- OOA4—(N(NinOO(NI(\IOO-A4AJ o^vomin^cocooco vomr^r^crunrnro—vDitoomvtooocor-iN oooooooooo + I oooooooooo oooooooooo cn >-ai(Nuo f'* —COP■sPO00i'P — roA4itO' - o - O—' Provided bythe NASA Astrophysics Data System A4 U.00000000 >00000000 4 00rnIN(NCNro—(M - —it^-^-0-0 o o — in o A4 ro o ro oo aioin vD O'it vD v£)oro 00 O'o vO A|OA- in oro in A4O''o CO A4roit A4 00—'vO o o o it AI — 00O' it —[^ vO roAJ— isD —A — AlO it O'o it it vt (T) A'1^ o o o o ro A4 o A4 A|— — A*A4 ^ OA' in vDroA4 a omit ro vDA4O' A A4O'AI in it—a o itairo A4 O'Ain in AJA|O' AJ A4init O' in0"ai O O'00— A4 init 00 <0— in OAI in —oo r- itvdro O (0A— — O o o AI — o o O ito - (^[^ o ro ai— O itA4 o 00 A4m 444 445 © American Astronomical Society A. U.LANDOLT:UBVRIPHOTOMETRICSTANDARDS H w n h4 <

Mean Errors of the Mean oo in o v v inino-coitos—in oooooooooo oo oooooooooo oo — itvDCOOOvoinoo—OCM oooooooooo oo oo^vD^-ooch —invD—in oooooooooo oo oooooooooo oooooooooo«^.^ — (NtNtNjrsiroror^—cnvor-fO(N(Nr oo —int^vtcNonoino=tmini COvOOOOCMCOCOint^ — oooooooooo — CMCO(Nit— oooooooooo oo — (Nh'- O CMvDit(N—00r- inh-cooooocovor^o — (NO —OCMCOOOOCOC" oooooooooo oooooooooo oo oooooooooo oooooooooo oooooooooo — CMCOCMCMÜOitCO oooooooooino oitif■ o oooooo* in —oomo O 00itO'CM it 00CO—o — or^oor'Ocovoino' oooooooooo oooooooooo CMCMtNCN —CMCMitCOit oco —ooooomincoit O' — 00r--itCM COOOO'OOOCOOOO'C-it oM3oor-M3oomm —O' it 00O—• M30'M3M3M30'M3000r> itititititititmmm mmmM3M3M3M>M3M3M3M3M3r-r^r-n'r-c-c-r- t-r--c-r-r-r-oooooooo CO OO'—' O' inM3000- in —oo[^o CO 00invDo if —(>M3*O'* oo coin—ocm OO'CMCOO — if 00it—O' O CMinOO— O' ooo—co- o —< if inO'oopmco GO —O cmoo it —C-O' + - -00 —00' -00 —00' M3 Q -ocMo —oitino -o —inM3M300 in o—oo in O'-oo in ooifmo oo in—M3 — O'moin o inoo o —O'CO O' CMO O OOO' O ifCMM3inCMOO—M3CNinOÍNinr^CMC-O-o* o-0-inin 0'OM30'inoooor^o(NifooO'mitifr^ococooifinh'coooi (N ifin-itvdcmO'M)oocoO'i^O'M3c-r-v ^ O'or- 00 M3CM O' oc-in + +II+I++II- v it oooooooooo MO CMin vO O00 CM itif00 oooooooooo o o (N - oo —r^- 00 CMC'O".' oooooooooo oo• CM if o o CM it if00CM co itin 00 —c- it (NO' it — O' O r-r^r^itifoooomoooo — or- — 00O'M3 OOOOCMOC-O' —M3 M3 —ifM3coinr-oooo mmmoooommmmm M3M3l^O0'O — — omit(NCM ooooino —OM3M3M3t^ o'o'ococooor-oo coo'O-O'O'oo-O'—coco<>oo'0't'OOoooa' CM f-0-(N 0 —0000' itmcoihM3r^ooM3a'm — OOOinoCM—if— C-COOCOOCMif- 0— M3 00 o oo + I oooooooo oooooooooo oooooooo C" init & OIf) o o ' l< — invd o CM O'— o o co mCN 0 O— it CO00 M3 r-o CM MOin• c- oocoi o —ooi O —if (N 00it oo in—cm* CO —CMM3V M3 —C- — OO00V — oor- if cm(Nin — vor^ c- inco cm oomo if M3C-— Provided bythe NASA Astrophysics Data System >00000 ) o J O—(N ) OMDCO(No cm »r^-o vD CM—itin o — o o o (NCOfOCsl — oo coinO' Ö o o — CO(NO o M) O' oo r- in o 0 o oo o O in00—C--OOO'OMOitOOOOifOOitOO-M3 cm oor-cooooitcoinoitinitoc-O'—itifit r^oo coooMinooooifino'ifitr-ifO'incMooo-co — O0(N(NoOOOOOOOO — o + 1++!+++III+ 1 I OQ T CO —’ o o (N - CM O O CO o o o r- r-O00ifC0M3M300t''M3 oooOitmcMoooo OOCMCMOO —CMif o o it (N in o oooooooooo o < o <. - CM( M300mC0M3C0O'00 00(N M3 (N00M>mMIO* itM300OM3(NCMin00(N M)M3coifOooor-0'0'in Oino(NPMifM3ifin'0 0-0' —M300'in(0000 r-cMOo —r^r^oi^cM — OtNt^MOCMCOO it —00C-CMCOOCM O'MOOOt'itC-OOOO'OO CMOOCMCMCMCMCMCMCM — ot^oot^itij-(N —oin 00 —O'OOCMCMinoOCM OOOOinM3 —COOCMM) — MOitM3inCM(NO oinooin —inififin ooooo'itcoi^inr^co I +-f 00 o o o vO - CM 0-—OO' o — V0 C' o o o o >0000000 >00-0000 j ooincocmoit -in in^tco—>t >0000000 >000000 >0-0000 ) -jdo—mCN ) r-oinvoro oooooo 0-0000 vOCO —CM C- 00vOCO O (No — o m coit oooooo oooooooooo oooooo it vDOCO—(N oooooo oooooo O ito h- incn—cmO' oooooo — vdmco oooooo it M?CM(N00 CO —O'it v o o o CM — (N CM O (N 0*0000 ooo 0'OoooM>r'Ooo — ififititOOCMM» coo-ooitc-mitoM) inoooocor-0'in-M3(N ooooooor-ooo oooooooooo CO CM CM - oooooooooo o CO (N o 0- if in cm m3 in r^o-ift'OoooMOifo o o o o in oo 00 iniNoooooooin Oif —coift'LnoocMin r-r-pooM —in^c-cMoo Oito —OOCM oooooooooo O' o — O'vDOOitOMOitOOit it CM — 00 I + >00000000 >00000000 ■ro —-in(T)-CN )vO

Mean Errors of the Mean oooooooooo oooooooooo (NinvDvDCNlN^tmmvD oo'CNO'ooin^ooo —o oooooooooo oooooooooo (N —lNvl-CNCN oooooooooo oooooooooo oin — in —oooinmo oooooooooo oooooooooo oooooooooo (NmcNi^m -—^tcNm r- —mt^cNoocNt'r- oooooooooo oooooooooo CNJ"— C\irO(N'—"—'—O'— oooooooooo oooooooooo O'OCOOOinoCNO'- (N (NCtOO —OOfO’ itr-cNmcN—it o < OOOvOCNOO —OOOOOOOOOO' — cNititcNmomcN moomo'o —ovX)cn OOOOOOO'O'O'O'O'O'O' O'O'O'OOOOOOOooo> or^or^oo —o (no oo-mmmm COOOO'O't^OO —CNCNm ocNinr- —O'ititm o —00-00 -oooot^ooo'oor^o't^ o—O'O'mo'O'oooo'ooi^-o'mooo'oo'ooo O'OO' —O'oooooot^ m oO'it— (• O'»X)vD > —om ' in—vD(N -O —OOO’ > mO'r-o ' o*mo ) —mo — CN’—(NvOr^vDIN m ocoit m O'vo m ovo it —O(N — OO'00 it O'O(N 00 vO—it — (Nm it 00O' m O' O' m— m O'r- — mh' — in it inooo o — o mitoo CN it m ooo in oo (N O'r-oo m O'it m — CN (\j (N oooooooooo oooooooooo oooooooooo OOOOOOOOOO (N(NJCN5tinm(N(NJ(NJ — 0 — m^-vûmvj- CN 00O— oooooooooo o o o o (N —in o in 00(N O vDvOv0 o o m (NCN <1- CNmO' oooooooooo (N it-o vo mit o mit CN Ü—(N ■vD —inCN O —vD (N vDO'v£) ocNmOitoor-* o m—oo O' it(N o it—(N — mCN (N —vOO o moovo< o r-1^m' (N O'—i it ooCNm (N —mt^'X>'X)'X)(NOCO OOO ——oooo (NCNmit CNitvû OOOOvOitvDt^'Dh’CNm — vDCNCNCNCNO I + m —in m — C'0''DCOv£)'vD(X)in sT *— t'C)C\|(N'-ît (N J o— ) OO'i ) —, i mo' ■ I+ ■ O’ m oo vo in CN in CN in (N O' vO - — CN 00 (N CN it - CN r- O' O' o — it it (N Provided bythe NASA Astrophysics Data System in p'vD(N - minvd o o (\i m — o m (Nin o o o o o — itCN vt oïtin ' (Nom - itin'X>co > >X)itt''o vo min 0 0-0 0 —r-o VD (Nit m oo(Nit in ito o 00(N— >X) —vO in voo CN —(N o in —oovo vO ito O' 00o - O'm— oooooooooo mm —incN(N(n(N<\iorsimcn oooooooooo (N —m(NI(N inr^^inr^r-vD —mm oooooooooo t\i —=t(\i(Nm(\!fNin iN!in^vDoin vom^o-mocNitvDit CNitO'vD —o'minmoo vtmm=titititincN(N m —momovomcN ot^mr^O'inmvOom mmooitmcN —mvoco — vDCOmt^CNOOOOO oor- —(>0000- m —omoooo'CNm itOOOmoCN —(NCN CN vdO'omm vo moinitminitit (NOOOOmOvDitCNvDOO IvDO —CNCNmit >mmr^-itmmcN 'm —oomcNOitr^ -oinitinininoo )(NvD —mo'oo 'mr-(Nvor-ooooo' ) —moinooo'm vOCOCNmoOOCNit r^oooo -—itm mor-o —r^mcN O'oi^m —m omoit —oom itr-cNoor' —m — mr-(NoCN i +-t 0 0-00 in -moo oooooooooo ooo ooo — m o ooo ooo oooooooooo oooooooooo CN ^vD — o in itoo oooooooooo ooo ooo — mvT ooo ooo in mO' oo (Mn r--0'mo'0''i)r-mit- vor-oomoo-oo —(N m<£>mmo''Omitm — ommitomititcNm cNmr-mcNmo'Dr-m movoo'ooititr^oo- itoinooincNOitvOvD r-moocNo -—O't'it O —OOitO-itO-itoo mmitititit —mmm mmmmitmcNCNitcN ocNom>x)0'itoo- (Nmvor^ —oO'XJmmit — cNCNCNCNmmmm OOOOOOvOOOO itcNmcNCN —ommm (NmcNO'r^ —itmo ooo'mcNh'itor-m momr^it'— mmm moooomr^oitmcNCN O'O'mcoooco —moo oo'mmoovD'nO'O initvomcNinm —o oo —cNvoO'CNvDvnmo (NmooitcNvooi^com CN —(N 000000-000 movoooh'ooo'o cNm —r-vD'DO'ooo' I in (N Ss v t- oin< in 0om o o in vd — (Nl' — O(N O ( o c o o o o — (N r' vd- it —in o o O' vdm— — mr- co ooo o r- m vo O' in- CN 00O' O' (Nvi- ooo ooo ooo ooo — -(N ooo CN m ooo

062 446 oo oo CO (S\ 447 © American Astronomical Society • A. U.LANDOLT:UBVRIPHOTOMETRICSTANDARDS > H < « PL|

ro Mean Errors of the Mean CQ I vN v vN v v — OOOCMOvfO o incMvfvf in cm- (Mvfitvf —vDCOCMO cococococococoititit ititititinininininininininvfvfvDvDvDvD'f vDvDr^t'r-r^t^r'r'i' cococococoitincocoit invfc-ooo' —OOOOO'O oocooovoin —ooitito o=tinin(Mitinoooit OOOOO'O' —OOO'O'OOO'O'OOO'COOh--h-OOCOOOOOO'OO-0't- OOOr-O' —OOO'O'O it —l^COCOCOitOvDl^ me- —ititcocvioinc' inOvDvDvfr^vDCOitC- OCOCMO'CO ——c-coco COititC-COvOC-OCOvO O'CMO'h'C-CMO' —CM- itvDC'CMinvDincOO'CO COOOI'(Mt-0'CMOin t^coooincoocoo'cot' ocor-vD(McoincMinit incM-incMooco — CO —it(Mr't'vDh'0'CN co —O'CMooo'O'inoo 00 —vOOOO'O'O'inO^- inc-(M —itifinc-vocM oitcooin —t^coco — CM-OvDvDvOCOO'I^ 00 O'—COcoinitvDCM OOCOO'CMCOCOOOCMCM vDvD —CO^tOOOOO^J"COCMOOr^COOCMt^CMin oooooooooo itCM- itCMOOCO—vf oooooooooo oooooooooo oooooooooo — CMCn^CM—5tîtCMCM oooooooooo oooooooooo — OO00(N^-(M vDO'O'OvDCNvD^-OO^t oooooooooo oooooooooo oooooooooo oooooooooo cnco^cncn^-ininin^- cnoo^vDCMincM^^-— oooooooooo oooooo< oooooooooo oooooo< (NI —(NfnrM^-OslrO(N(NvOCN^J—(\|(\l(N* CO=t(M(M —il-COfOr^CM oooooooooo oooooooooo oooooooooo CO —ititCMCMCOCM 00 —oooooocn^tin oooooooooo oooooooooo OOOOOOOOOO 000000-000 =too(MOitvj-itvoin ’-vDOOOOvDvDvOOO^*'- COinoOt^fO—CN^-OOCNOvûC vf itcor^O'coor^ — cm00oinc>cnco - O—CM + I o — vfoo —000r^o cMinitO'invfO' oco inr^oor-itoor-cooit — O'r- oinininititoinvfr^ oooooooooo (MCMCMO'COvOitCOOCO + 1I O CO CM O O' 00 CO O ' invOCMCOCMCO —vDitr^ cor^cocMcoinitvOit- O'O'COh-CMinCMOOCMin 00 it CM CO itmcMi^cMCOií-initvo ü-cMCMvOvDrovDinorn OCMit'sDvI-t^inCMCOCO CM'£>'£)Oinox> co invD ititCMvDOCOvDCMCOO' 000 000 — - O O' oooooooooo 000 000 in — oooooooooo 000 000 — CM oooooooooo m —cmcinit 000 000 oooooooooo it invd 000 000 — -CM 00 O oooooooooo o o C\l If) O00 — COOvOO'O'vDO'sDCM - in I + — oo' in C" it it o itco in —001^ O COC'00itvD in cmovo O' cm1^co—in it —inCM00 00 —CMvDCO vO vf—COOitO' O —it00 OOOCMOOOOint- 00 govor-vDin it incoocm O CMitC^CO CM CO—OO' co r'oin 0000000 0000000 CM ^—it 0000000 00 incoito (Mr-itcoooo- 0000000 0000000 o coincmvo 0000000 — (MOCM in^^tvocooit o on —(N00 0000000 0000000 it —CMinCO 0000000 0000000 (M —OCM o o vocnoo vd —cmcoin ^ it00CMCO 447 448 A.U.LANDOLT:UBVRIPHOTOMETRICSTANDARDS © American Astronomical Society

Table IV. (continued) o 00 in T— ,— oooooooooo in ocoer,r-mitencn—vDir> oititr-oc-o -covnvooocNr'OomococN mo'UOititcocoititvo 00 —OOOOt"- coininr'CDitvD=foovD 00 -0000000 oooooooooo oo oooooooooo oo — CNii-N(NtN OfNinoinocoD'CN— com oooooooooo oo it — CO —oco 043430'l^itinitinco t^t^r^OOOOOOOOOOOOOO OOO'O'O'O'OO'O'O'O' vor^r'O'oo —(Ncoin O'OCOUOCNCO —00430 ouoinooooocNcocooo r"Oititita' oooooo—oor- —o-O'itr^OitO' 00 COr--itCOCOvD— ["••or- itvfitovDooin oooooooooo oooooooooo it=t-itCNCN —(NitvDCO — OCNOOOOOOOoooooooo oooooooooo 00 (Ni,O—OOCN'-OOOOMO'vD oooooooooo ooccoooooo oooooooooo oooooooooo fsj (NJîj.(T)(M(\j•—CNÍN,—INO00 D'O-ommocNjitorn moono^-oiN—movo ititincNitititititit itinooititcoitoLn r"tCNro^43oocNin40 co —inin'vOcO'vO—ovoin — O(N”04 itvOO'inoOO'vDCO —it OOOOOOOOOO oooooooooo — Ovl.;--00CNtN(N(N(N'-(N(N in —coitcoo(Nin O —COO'COitOOOOCN'vD (0 —04431"'coin itcr>0OitO'COv£)inO40O co —cnoooocNitoo(> incNitCvjcN —(Ncoinco cooo'^-oor-vDitcoc' oooooooooo itCNit —OOOOOr-OitOOOOOOOO O'r'O'oor^ooo —O'[^ooooO'ooooor"coO'43oor"’ oooooooooo oooooooooo oooooooooo cor^inoitoit-moo cNooinnof^cNitcNcot^ ["'(NI^OitCOOinO'CN incNoor-itooLninro COitr-vOO- 04^043 (MO, —OCNOOO t^it43 43—CNO'O'CN r"C"itCOO(T)(N —OO' 43(Nroi^itooi"'itinin — oOCNOOO or-CNor^- CN—43r- + -l--f-l- 43 r^OOOOOD- - CN ÍOOOOOOO oooooooooo s s ,ititr"(Ncoino'0'43it f" 00— in itCN— inO'[^inr"r'0'Oitoo ooin —oooococoo it- CNr"r''DO0'43 r-cnmcN-43CDoinco it—cncnoor'in^-43inn3mcNooocN43a^r" 000000-000 oooooooooo o CN — in o 043CN —0inOO'CC-t(N'N43oinooo43(N4)incNin it4)43 —coin-O-tCD(Nitm-OCNcnr^rr)OOitt^-inCNCNO(N o oooooooooo o o (N CN 00 (N. oooooooooo O' f" 0 —000 — 04COCNeg — cn + -*--»-tiI1+ + J ^04 ■ 00vD ■ cor- ■ it— > CN43 > mit • CNitc ■(NO* > itO'• o o CN in 00 o o o CN CO vD CO in oooooooo (N O O' ^0 > o ) o • -CN ) OCN 00 o o O' (N 00 vD N? o o — CO 4) it co r" CN C" O CO 43 00 — it Provided bythe NASA Astrophysics Data System 4CNOOCN (N—CNC404O- > coin-o t- o— j itenn ro n-— CO 43IN oo o["* o o CO it-CN — (NOC- o o 00 O—O' G' GO(Nf" — O'0043 O 40-00 o o CO —CN — m^oo it 0043CN 43 COr-— 04 it-00 CN vO43in CO OvD =t O'IMl" in crvo 00 O'CN(N 00 —43 O'43C0inin'X>CNCNCN00 cofoo'r"0'(NCNitr^o itO'incoin'OcocNinin OOOOOOOOOOO COiNr'OOCOOOitOO'O incN —ooitin'Noooo' — coino'mooir>o OO'.0 43in43itit(N— Or-CN —0000itit430 (N —(N(N(Nit(NCO r-'COitOO —OitCNOit(N•if it00 43itO'00U0-oin (N —OOOOOOOO OCOCNCNCOCNCNCO —(N vOvOifCOvi-rvitOOvDCN oooooooooo oooooooooo coooo —oooooooooooooo — voincor^oocNcocoitr^cN-coin-r^covtcN — OitinOOC-OvDCNVDO--OOOOvOt^C'O oooooooooo oo 0-00000000 OO oooooooooo oo ocouoitonoo-o'in (N —O'COCOCNOOO'OO oooooooooo 0- í; 0- o CO 04 oooooooooo oooooooooo — inoooooooo (NocNincoin —(Nco r'-init-ito'oocrin^ — oooooooooo oooooooooo oooooooooo 0 —00000000 '-r^ —(NCNrorMtNnn VD —vDlNfOCNh-Oît oooooooooo oooooooooo oo OfNOOOOOOOO oo m 00.'iIN0)—(N- ^OOCNOOl^CNt^ —invl-CN — OOOOOOCN- O' o 00 - — oooo* — C" CN inoC" oo r-in in oooit CO ~<.*■04CN vO in—43coo O'itOO'vO — m o O' o in (N - o- oo — CO — CNCN- CNOOOCOCOCOCOC3CO OOCNiDinititCNitCNCN CN00itinit43inr"vD43 CN0043CN430'inr'0' (NüOCNinO'OO — ocooinoooooo itinococoititititit ininitcovOo[^co43it in430'oinoitoinco 04300 —Or"C043C0CN OOOO —it—Oit cor"0'in43ino'inoo- r'OO'O'ino —itin — 43O'=tC0(N43r'00(N OOCOitCOCNOCNOOOO — 4343in-COCOit inoooincNininNin OititCO —00^-04(004 oooooooooo -l-l I+ inooino4r"CNin43 —o oooo —inoino 0OC> o o CO - CO l^ oooooooooo o o (N - it (N itOOCOCOCOinoOvOCNCN or^40ot"-c>

Table IV. (continued) O 00 ID CQ > 3 CQ I I n --uegeg--'--- COCOOO —ititit^it egeg i^ooinini^i^vi) r^h'^-O'ocoitLnint^ vDitoovOit —oooino egegegegegogegegegeg ititino —coitititit —Lnegooo'- — egegrgegfNcgeg o eg' egeg- —coitino-o egeg<>oooor^itr^egin — coeginoco 5toOl^vOO=tititvD^- aooegooo^eg’— —O' mooo'ego'iginco —itcoooooomitooom-mvor^ r>-it O'—ego—ine'oitO'ite'egooe-co oooooooooo oo— vo —e*inege-ocoO'egO'O'inoooe-in ooo —ooo——ooo^ooo—eg vom —'-cooocoovocg + - OOOD'^ —OvDO'O^*— t^C0C0C0v0C>O —oo vDito —cor^cooincg r^ooot^incgogco'-co fnegovDvite'OCOvD m—itcooegcovommo' coegoinvDitvoocoin it—itr-oejcoinmino co i^O'inoin—e'oovoe- c>inor^o(Noo —(Ncg cNinstoo^-r-inco-^- acoinitoooit —eg—coi^t^vor^egincovooain + +I++I+++II1+-»- — (Nin^tNro^»- oooooooooo OOOOOOOOOO CN(NlOCNCN(N(N^-'-CN <>0OvD —O'—lOCNt^Csl co o - it o—• oo —in*0 (Nr, oint^cg i +• N C'e>r-cooegit—r^- -- —ego- it —ou.mmm it —egegcoin co egg?mvoooo—e-O'vOit- egegegegegegegegegeg egegegegegcococococo coo —egitcoegmmeg ooco —itmitomoo oooocoo —o—oeg co —cocoocomit ito —ejitinoitoito — O'O'vocoegmoO'O'co egoe-egegooegcoovo oo vOO'ocoeg—O'oooO' in o CO o + g-+ii+ O vD 00 - o o co — in vo it—cncoeg— — inoovnovor^inoit o o ineg o c o co —r\i*—(N oooooooooo ooo o — ’—O co o oooooooooo r^cooooovoincNO'fn —ro oooooooooo ooo oooooooooo ooo CN —mo".or^tMocNeg oooooooooo ooo oooooooooo oooooooooo oinno’-inmo^inin — in ) 00it— ■ vOo- ■ vtoin Provided bythe NASA Astrophysics Data System co it— r- eg i^ inco CO o a in- il- 00vD ^ eg — ^ eg - vD it — r^voiN(N O O'—v£)oo O' vog?m o voegin co egitvO— e— oO'co - cor-vo oo mcoO'it 00 COO'o co egint^— CO it00OvO co —OO' — o o o oo eg— oo voin o COtN —*— o (N 00 vO itO O COo O CO O it vD co vO oit vo ineg O' 00 oo e-— OOO vD O'it vD O'CO ooo in covo ooo ooo v£) 00 vOc> 1 < CQ(B TJ ain TJ •h min 'H mTJ •H -HL m «i •H —lj! +i P p - x: ß •H a, it in JE (B> •H tBß -i prtih TJ üL T)

-H ■-» .CTJs-H •h egsn m e- •H OJ e P -Hu I (B P H (D (BL+ m (Bai O inm (B x: pvoo -H JQI x: ßit x; O'(Bm P (BM p —x:co O TJvOII p o cn-i m+ Ätn j ooovO •h e-— -H O'eg (B Q< L tB O'—o J (BL x: p- Uh OL •h in(B •—I 0>"H JOB) CO •H L> •H p-H > H CO • •H P> •H O •H TJ fl •H TJ-H in -hit (B -H P (BL eu in eu P (B-h o CU(B in o -H (B >(D L (B (B -H (D -H(B (D x: Ë XI m in a» flin (D •—Ifl O <—i in m (B >b L (B (B -H O -H(B fl OP Lin (B > O -Hß (BUT! (D PO m «Da) (B a in m in color index values obtained at each telescope were weighted by the number of observations and the mean error of a single observation obtained at that telescope (Barford 1967):

’ WjAVSj + W2X /s\ Weighted result = 2 wx/s\ + w2/s\ w + w 1/2 Weighted error = x 2 2 2 1 . Wj/s + w2/s 2 J Fig. 11. The number of program stars observed in intervals of 0 ?! in the {B — V) color index. where u;, is the number of nights, X¡ is the magnitude or color index, and s¡ is the mean error of a single observa- and from Harvard Annals, Vol. 101 (Durchmusterung tion. of Selected Areas). Table IV contains the final magnitude and color in- The coordinates for the stars in Table IV have been dices for the 223 celestial equatorial stars that were ob- precessed to the 1985.0 equinox for ease of use. The served at the 0.4-m and 0.9-m telescopes. Each star was original coordinates were taken from the sources cited observed an average of 20.7 times on 12.2 different above. Note that the stars in Table IV are ordered by nights. The star identifications have been taken from the right ascension. Finding charts for the Selected Areas, Henry Draper Catalogue, the Bonner Durchmuster- Feige, and Giclas stars may be found in Landolt (1973). ung, Feige (1958, 1959) lists of blue stars, Giclas stars in Proper motions have been taken into account in com- various Lowell Observatory Bulletins (Landolt 1973), puting the coordinates for the half dozen largest proper motion stars. Columns 4-9 give the weighted magnitude and weighted color indices on the i/i? FÆ/photometric sys- tem as defined by stars in Landolt (1973) and Cousins (1976). Column 10 indicates the number of times, «, that each star was observed. Column 11 gives the number of different nights, m, that each star was observed. Since the numbers in cols. 4-9 are mean values, I decided to tabulate the mean error of the mean magnitude or color index in cols. 12-17. This kind of error is defined by 2 1/2 [2(x:f — x) /n{n — 1)] , where is an individual ob- servation, x is the average value, and n is the number of observations. If anyone needs the mean error for a single observation of any quantity in cols. 4-9, they need only multiply the appropriate number on the same line in cols. 12-17 by («)1/2 where n is given in column 10. The mean error of a single observation is defined by [2^ — x)2/{n — 1)]1/2. The numbers in column 18 re- fer to footnotes at the end of Table IV. Figure 10 illustrates the number of program stars in intervals of 0.25-F magnitudes. Figure 11 shows the number of program stars observed in intervals of 0.1 mag in the (B — V) color index. Fig. 10. The number of program stars observed in intervals of 0.25 V Perusal of Table IV indicates that several of the stars magnitude. obviously are variable in light: HD 47761, HD 57884,

© American Astronomical Society • Provided by the NASA Astrophysics Data System 1983AJ. oo oo CO (S\ 1/2 HD 191639.Theaverageweightedmeanerrorofasin- HD 60826,SA104306,107970,188934,and 0.0134 +0.0056magnitudes.Therefore,atwo-sigma mentioned sevenobviousvariablestars,wasfoundtobe gle observationoftheVmagnitude,excludingafore- being apossiblevariablestar. error wouldbe0.025mag.Anystarwhoseweighted 451 A.U.LANDOLT:UBVRIPHOTOMETRICSTANDARDS 0.025 maghasbeennotedinthefootnotestoTableIVas mean errorofasingleobservationwasgreaterthan third columnshowstheaverageweightedmeanerrorof index isgiveninthesecondcolumnTableV.The ror ofasingleobservationFmagnitudeorcolor single observation.Figures19and20illustratethe there wereanaverageof20.7measuresperstar,the the meanobservedmagnitudeorcolorindex.Since dolt’s (1973)equatorialstandardstarsonJohnson’s sessed bythestandardstars. showing therangeofcolorsinthesecolorindicespos- plots, respectively,forthesenewstandardstars,thereby ble IV,andareself-explanatory.Note,though,thatin third columnnumbersare(20.7)smallerthanthose given inthesecondcolumn. each figure,theordinateisweightedmeanerrorofa (U-B), (B-V),and(V-R),(R-I)color-color function ofV. a functionof(5—V). Fig. 12.Theweightedmeanerror of asingleobservationinFasFig.14.Theweightedmeanerror of asingleobservationin(Ä—F)as B-V R-I U-B V-I V-R The numericalsizeoftheaverageweightedmeaner- © American Astronomical Society • Provided by the NASA Astrophysics Data System Kunkel andRydgren(1979)observedasubsetofLan- Figures 12-18havebeenplottedusingdatafromTa- V 0.0124 +0.0050 0.0134 +0.0056 0.0116 +0.0060 0.0095 ±0.0058 0.0090 ±0.0042 0.0228 +0.0119 Mean errorsofasingle observation ofthemean Table V.Erroranalysis. 0.0029 +0.0012 0.0020 ±0.0009 0.0050 ±0.0026 Ö.0027 +0.0011 0.0025 +0.0013 0.0021 +0.0013 A (V—r)=+0.0002±0.0172andA(V-i) 5 FR7photometricsystem(Johnsonetal.1966).Recall sins’. Theirresults,transformedtoJohnsonetal(1966), that inparticular,the/bandisquitedifferentfromCou- Figs. 21and22.Theregressionrelationsare: minus Landolt.Thesedataareillustratedgraphicallyin pared todatainTableIVthispaper.Onefinds They alsopublishedcolorindiceslabelled(V—r)and are tabulatedas(F—R)and/intheirTableII. and (V —i)intheirTableII,whichtheyleftontheRCA 31034A naturalsystem.Theselattervaluesmaybecom- function of[B—V). Fig. 13.TheweightedmeanerrorofasingleobservationinLas = —0.0302±0.0094inthesenseKunkelRydgren [V-R )paper=+0.020260.94498(V-r), thisKR Us paper=+0.021981.01187(V—i). KR ± 0.002800.00328 ± 0.003280.00734 451 452 A. U. LANDOLT: UBVRI PHOTOMETRIC STANDARDS 452

Fig. 15. The weighted mean error of a single observation in ( Í7 — 2? ) as Fig. 17. The weighted mean error of a single observation in (/£—/) as a function oï(U — B). a function oî(R— I ). Moffett and Barnes (1979) observed 189 of Landolt’s (1973) equatorial standard stars. These measuremeñts (V-R)mb, also were tied into Johnson et al. (1966) BVRI photo- ± 0.00207 ± 0.00440 metric system. A comparison of their results with Table IV herein gives AV= + 0.0026 ± 0.0095, A{B-V) and = + 0.0009 ± 0.0117, A (V — R ) = + 0.2052 ± 0.0959, and J [R -1) = + 0.0060 ± 0.0330, in the [B -/)this paper = + 0.04245 + 0.87342 (R -I)MB sense Moffett Barries minus Landolt.One should recall ±0.00246 + 0.00568. that the RI differences result from a comparison of data I observed 52 of Graham’s (1982) stars. Since our ob- taken at different effective wavelengths. These relations servations were obtained with nearly the same equip- are illustrated further in Figs. 23-27. The regression re- ment at the same site, our results ought to agree. The lations are: coiriparison is not quite fair, though, since, although I (B - Hthis paper = - 0.00058 + 0.99958 [B - V)MB, observed these 52 stars an average of two times each, ± 0.Ö0224 ± 0.00257 half of them were observed only once^ Given that caveat, intèrcomparison of Graham’s (1982) data with those in Vw = Vr this paper MB Table IV herein show AV = + 0.0038 ± 0.0096, -0.00398 + 0.00188 (2? - F)this paper, ¿(£_ F)= +0.0024 ±0.01 Ü, A(U-B) + 0.00181 +0.00208 = - 0.0148 ± 0.0343, A(V-R)= - 0.0039 ± 0.0Ö98, and A(R—I)= + 0.0031 ± 0.0113 m the (V-R )this paper = - 0.03206 + 0.71652

Fig. 16. The weighted mean error of a single observation in ( F — Æ ) as Fig. 18. The weighted mean error of a single observation in ( F — 7 ) as a a function of(V—R). function of (F—7).

© American Astronomical Society • Provided by the NASA Astrophysics Data System 1983AJ. oo oo CO (S\ stars. TableIVinthispaper. 453 A.U.LANDOLT:UBVRIPHOTOMETRICSTANDARDS Fig. 19.The{U—B),{BV)color-colorplotforthenewstandard21.AcomparisonofKunkel-Rydgren’s{V—r)with{VR)in trated graphicallyinFigs.28-33.Theregressionrela- tions are: sense GrahamminusLandolt.Theseresultsareillus- and stars. Table IVinthispaper. Fig. 20.The{V—R),(R—I)color-color plotforthenewstandardFig.22.AcomparisonofKunkel-Rydgren’s (V—i)with(F—/)in wr © American Astronomical Society • Provided by the NASA Astrophysics Data System [B -V)=+0.002410.99304(B, (* -/)thispaper=0.00598+L00740(R-I). (V-R ),hpaper=+0.005600.99590(F-Ä), (tf- 5)paper=+0.001431.02615[XJ-B), V = thispaperJG Ms paperJG jg isJG thisJG ± 0.002160.00252 - 0.000840.00467[BF), this paper ± 0.002490.00536 ± 0.00244+0.00284 ±0.00518 +0.00597 ± 0.002260.00470 job oftyping.JenniferLandoltassistedwiththedata cess ofthiswork.Foremostaremywife,Eunice,forher thank thestaffandDirectorsV.M.BlancoP.S. helpful discussionsovertheyears.Itisapleasureto support andDr.JohnA.Grahamforhischeerful for theirhospitalityandassistance. Osmer oftheCerroTololoInter-AmericanObservatory superb CTIOstaffincludingL.Alday,E.Cosgrove,C. Czuia, A.Gomez,R.Gonzalez,G.Martin,D.Matur- have takenmuchlongerwithouttheableassistanceof Ugarte, andR.Venegas. ana, M.Naverrete,C.Poblette,J.Rios,O.Saa,P. entry atthecomputerterminal. Barnes, W.P.Bidelman,V.M.Blanco,R.Canterna,O. Linda Johnston.Gauthierdidherusualexcellent Many, manyindividualshavehelpedensurethesuc- I acknowledgewiththanksaidfromtheeverhelpful The datareductionsandcomputergraphicswould Helpful thoughtsarosefromconversationswithJ. 453 454 A. U. LANDOLT: UBVRI PHOTOMETRIC STANDARDS 454

Fig. 23. A comparison of MofFett-Barnes V magnitude with the V Fig. 25. A comparison of Moffett-Barnes (B — V) color index with the magnitude in Table IV in this paper. (B —V) color index in Table IV in this paper.

J. Eggen, J. H. Elias, J. D. Fernie, A. D. Grauer, J. B. Publ. No. 18; comp. = companion; dbl. = double; Irwin, R. E. Luck, J. McClintock, E. C. Olson, C. L. em. = emission; F = Feige; G = Giclas et al. nos. in Perry, G. Tammann, J. Tohline, and H. Weaver. Lowell Obs. Bulletin proper motion lists; GC = Boss’ This project has been supported by Grants 77-3218 General Catalogue of33, 342 Stars for the Epoch 1950; and 82-0192 from the Air Force Office of Scientific Re- GCRV = General Catalogue of Radial Velocities-, search. HD = Henry Draper Catalogue-, LFT = Luyten (1955); LTT = Luyten (1957); M = absolute magnitude; MWC = Mt. Wilson Catalogue of Be and Ae Stars (Merrill and Burwell, 1933); PC = Jenkin’s Parallax APPENDIX I Catalogue (Yale); pe. ptm. = photoelectric photometry; The literature has been searched for additional infor- R = distance; rel. tt = relative trigonometric parallax; mation for the BD and HD stars in Table IV. Similar r.v. = radial velocity; SA = Selected Areas; sp. bin. information for the Selected Area stars has been listed in = spectroscopic binary; sp. cl. = spectroscopic classifi- Appendices I and II (Landolt 1973). MK spectral types cation; sp. tt = spectroscopic parallax; T = tangential for the Selected Area stars may be found in Drilling and velocity; F = Barney (1949); /z = proper motion; Landolt (1979). Abbreviations used in this Appendix in- 77 — trigonometric parallax. clude: abs. 77 = absolute trigonometric parallax; The star names which follow appear in order of in- BD = Bonner Durchmusterung-, C = Cincinnati Obs. creasing right ascension.

Fig. 24. A comparison of Moffett-Barnes V magnitude with the Fig. 26. A comparison of Moffett-Barnes (F—/? (color index with the (B — V) color index in Table IV in this paper. [V — R) color index in Table IV in this paper.

© American Astronomical Society • Provided by the NASA Astrophysics Data System 455 A. U. LANDOLT: UBVRI PHOTOMETRIC STANDARDS 455

( R-I ) (B-V)

Fig. 27. A comparison of Moffett-Barnes [R — / (color index with the Fig. 29. A comparison of Graham’s (1982) V magnitude with my (R — I) color index in Table IV in this paper. [B — V) color indices for his stars.

HD 315 = 4 Ceti = HR 11=GC BD - 12°134 = NGC 246 = 118 - 74°1; (Perek and 114 = BD — 3°2 = GCRV 57; GC gives Kohoutek 1967), object discovered by Herschel in = +0?0014;/¿<5 = 0"003; GCRV gives Vr = -b 13.2 1785; called a planetary nebula by Curtis (1918), his km/s, apparently from Christie and Wilson (1938); Fig. 2; van Maanen (1929) measured motions: //a Abt (1970) lists additional r.v. measures; sp. cl. B8p Si = — 0"041, abs. 7T= + 0"009; van from Cowley (1968), and B8IIIp Si quoted by Hoffleit Maanen apparently was the first to mention the exis- (1982); pe. ptm. by Cousins (1962): F = 6.42, tence of a comp. —4" distant; Minkowski (1955) indi- [B —V)= — 0A5, [U — B) = - 0.46; by Crawford cated a double stellar nucleus, probably hot sd + G; (1963): (B-V)= -0.15, [U-B)= -0.46; Cowley (1958) rediscovered it as a blue object; Min- ß= +2.707; and by Golson (1970): F=6.45, kowski (1960), more on companion. Klemola (1962) {B-V)= — 0.136, [U — B)= -0.457. found sp. cl. = Op; pe. ptm.:F= 11.76, HD 2892 = BD + 0°71; star 40-0-no. 6 in Sanders [B — V)= — 0.33, (f7-J?)= - 1.24; [iacosô (1966): pe. ptm. V= 9.31, (1? — F) = + 1.35, = - 0"030, ii5= - 0"006; O’Dell (1963) gave pa- (U-B)= + 1.39;HDsp.cl. = K5. rameters for the planetary; Greenstein and Min- 0 BD — 15 115; Cowley (1958) discovered object to be kowski (1964) gave sp. cl. = sdOfe, with Mv = +3. blue, with sp. cl. B5, tiô = + 0"032, = + 0"006; BD—H°162 = No. 352.14 in Second McCormick Klemola ( 1962) found sp. cl. B2, //a cos á = + 0"004, Catalogue of Proper Motions; Vyssotsky (1953) dis- ^ = + or022, F = 10.88:, (B - V) = - 0.23, covered blue nature of star with motions [U — B) = -0.79. f¿a = — 0"032,/z<5 = — 0"028; Osvalds and Osvalds

-0.045 -0.030 -0.015 ) V * 0.000 3 6 O . • • * J ^ 0.015 ) 3 0.030 0.045 0.060

(B-V) Fig. 28. A comparison of Graham’s (1982) V magnitude with my V Fig. 30. A comparison of Graham’s (1982) [B — V) color index with magnitudes for his stars. my [B — V) color indices for his stars.

© American Astronomical Society • Provided by the NASA Astrophysics Data System 1983AJ. oo oo CO (S\ my (V—R)colorindicesforhisstars. Fig. 32.AcomparisonofGraham’s (1982)(V—R)colorindexwith HD 12021=BD-2°329;Cowley(1958)foundobject HD 11983=BD—8°349;star200-10-no.2inSanders HD 5505=BD+0°146;pe.ptm.fromPriser(1966): my (U—B)colorindicesforhisstars. Fig. 31.acomparisonofGraham’s(1982)(U—B)colorindexwith 456 A.U.LANDOLT:UBVRIPHOTOMETRICSTANDARDS © American Astronomical Society • Provided by the NASA Astrophysics Data System ficosS =—0"029,ju—0"032. (U —B)=0.40;motions:/xcos¿=O^Oll,//^ sp. cl.=B7;pe.ptm:V=8.86:,(B-V)=-0.10, to beabluestarwithsp.cl.=B8pandfi sp. cl.=K5. (U —B)=+1.82:HDsp.cl.K0. (1966): pe.ptm.:F=8.15,(Æ-F)=+1.52, cl. =Opwithpe.ptm.:F=11.23, object notawhitedwarf;Klemola(1962)foundsp. found rel.ir=—0"021,withsp.cl.=B2,concluded (B —V)—0.10,(UB)=—1.10;motions: a0 a V=S.99,(B-V)= -f1.09,(C/-^)=H-0.96;HD a = -0"007. = -0"009,ii—0"006;Klemola(1962)found 8 HD 36395=GC6836BD-3°1123GCRV HD 21197=GC4076BD-5°642GCRV BD —2°524=F29;Feige(1958)foundstartobeblue BD —0°454=SA94305;Buscombe(1980)quotespe. HD 16581=BD+0°442;Golson(1970)pe.ptm.: my {R—I)colorindicesforhisstars. Fig. 33.AcomparisonofGraham’s(1982)(R-1)colorindexwith r.v. =+10.0km/s;anUBV standardstarJohnson r.v. =+10.9km/s;Wilson (1967)gives tions:/i =+0".n\,ii - 2"098;GCRVquotes individual r.v.:PCgivesn= 0"163, andusesGCmo- Joy (1923)findr.v.=+11.4 km/s;Abt(1970)lists 3349 =PC1255C683G99-15;Adamsand (B —V)=+1.16,(UB)=+1.11withM ley, Hiltner,andWitt(1967)foundpe.ptm:V=7.88, (B-V)= +1.17,(U-B)=+2.28;and,Cow- ptm: V—7.86,(B-F)=+1.16,(U-B) finds sp.cl.=K4V,andM+6.7;Stoy(1963)pe. (B-V)= +1.16,(U-B)=+1.16;Wilson(1962) sp. ir=+0H00,pe.ptm:F=7.85, as tions: fi=-0!'243,fig0"773;GCRVgivesr.v. vidual r.v.:PCgivesir=0"06l,andusesGCmo- v (1923) giver.v.=-11.3km/s;Abt(1970)listsindi- sp. cl.=B3-B5IV. ptm.: V=10.27:,[B—V)=-0.11, c c v (U —B)=0.63;motions://cos<$=+0"011,// Feige (1959);Klemola(1962)foundsp.cl.=B4;pe. with sp.cl.=B3IIIandr.v.+2km/s;chartin HD sp.cl.=B9. (U —B)=+1.60,andsp.cl.K5III. ptm: V=8.89,(B—V)=+1.42, a 1886 =PC712LFT282C453;AdamsandJoy Crawford, Golson,andLandolt(1971)pe.ptm: = 6.80and7’==62km/s. = +2.26;also,Stoy(1965)pe.ptm:F=7.84, a5 V= 8.192,(B-V)=-0.062,(U-B)=-0.278; V= 8.19,(B-V)=-0.065,(U-B)=-0.269; = -11.8km/s;Roman(1955)findssp.cl.K5V; = +0"005;Berger(1963)gaver.v.—9km/sand 456 1983AJ. oo oo CO (S\ 0 HD 46056=BD+4°1291BAL2666MWC HD 47761=BD-4°1607GCRV4321;Neubauer 457 A.U.LANDOLT:UBVRIPHOTOMETRICSTANDARDS HD 50167=BD+1°1561;Golson(1970)pe.ptm.: HD 52533=GC9248BD-2°1885GCRV HD 57884=BD—3187GCRV4904; ¡i =0"017;AbtandBiggs(1972)listextensiver.v.val- Double Stars,LickObservatoryPublications,Vol.21: ues; Johnson(1955)pe.ptm.F=8.19, cl. =M1.5Ve. Hiltner(1956)pe.ptm.: K=8.15,(2?—V)=+0.19, (B-V)= +0.18,(U—B)=-0.76;sp.cl.08; (R—I)= +0.85;Buscombe(1977)quotessp. (B —V)=+1.47,(U-B)=+1.21,R=6.85, cl. =MlV;many,manype.measures(Blancoetal. and Harris(1954)withpe.ptm.:F=7.97, polarization measures;Mendoza(1958)listsobjectas r.v. =+18km/s,notesstarissp.binarywith BAL 2666fromR.Baillaud’swork;GCRVgives (Æ-K)= +1.47,(U-B)=+1.21,andsp. M= —4.1,inNGC2244.Buscombe(1977)quotes (U-B)= —0.74;M=-5.1;mM=11.8;also 808 =GCRV4169;seep.190inIndexCatalogueof a Bestar:seeTable2,p.216;ContiandAlschuler (1971) saystarinMon2assoc.,withsp.cl.=08V, sp. cl.=B2V:pe;alsohaspolarizationmeasures; [-V)= +0.17,{U-B)=-0.62;M=-2.0; Hiltner (1956)foundpe.ptm.:F=8.63, GCRV quotesr.v.=+29.0km/s,and¡i0"019; km/s, withvariablevelocityrangeof70km/s; pe. ptm.:F=8.17,(B-V)=+0.19, Mendoza (1958)foundpe.ptm.:F=8.62, lists objectasaBestar;Buscombe(1977)quotessp. (1943) givessp.cl.=BOek,averager.v.+29.0 [U —B)=-0.75,andsp.cl.=B2III. 1968); Eggen(1979)pe.ptm.:V=7.98, cl. =B2Vpe,andpe.ptm.:V=8.11, {B-V)= +0.20,(U—B)=-0.67;1.51kpc; {B-V)= +0.12,(£/-£)=-0.61. e © American Astronomical Society • Provided by the NASA Astrophysics Data System v 4611 =ADS5705;GCgivesju-0"003, B values givenbyCousins,Lake,andStoy(1966);Conti ptm.: V=7.68,(B—V)=0.07,(U-B) and Alschuler(1971)saysp.cl.=08.5V. {U —B)—-0.95,andsp.cl.=09V;Stoy(1963)pe (1956) foundpe.ptm.:V=7.70,(B—V)=0.09, (1943) foundr.v.=+5.5km/s;HiltnerandJohnson Crawford, Golson,andLandolt(1971)pe.ptm.: HD sp.cl.=K5. pe. ptm.:F=9.4withsp. cl.=C4+,3;also gives r.v.=+55km/s,presumablyfromSanford HD sp.cl.=N. (1944); Vandervort(1958)pe.ptm.:F=8.40, [B —V)=+2.19;sp.cl. =R8;motions:fi V =7.85;[B-V)=+1.546;(U-B)=+1.72; a c V =7.861,(B—V)=+1.534,(£/£)=1.721; V= 8.40,[B—V)=+2.19, withsp.cl.=C5,4; a = 0"007;GCRVgivesr.v.+5.5km/s;Neubauer = +1.16,andquotessp.cl.B6;samepe.ptm. — +0"004,¿¿=+0"010;Buscombe (1977)quotes <5 BD +5°1668=GCRV4954PC1755GL HD 60826=BD+2°1715GCRV5071CVS HD 65079=BD+3°1848MWC188GCRV HD 72055=BD-6°2620;Sanders’(1966)star820-5- HD 84971=BD-2°2986; Guetter(1968)sp. HD 79097=GC12691BD-6°2839GCRV HD 76082=BD-0°2087GCRV5854PC2125; n by LuytenandEbbighausen(1935);GCRVgives 273 =LET527G89-19;PCgivestt0"263,/Li km/s; Kuiper(1942)quotessamer.v.;Joy(1947)finds r.v. =+26km/s;Popper(1942)finds22 r.v. =+28km/s;Eggen(1979)pe.ptm.:F9.80, quotes pe.ptm.F=9.75. combe (1977)quotessp.cl.=M5V;Buscombe(1980) and Harris,1954),pe.ptm.:F=9.82, (R —/)=+1.21;andi/RFstandardstar(Johnson (B-V)=+1.55, (U-B)=+1.12;R=8.41, star; r=1.74kpc;Stoy(1963)pe.ptm.:F=7.83, Petrie andPearce(1961)r.v.=+2km/s;Mendoza quotes fi=0.021;Heard(1951)r.v.+2.6km/s; cl. =R8;r.v.+44km/s;//0"075,ji vort (1958)pe.ptm.:F=8.65,(B—V)=+2.46;sp. and notesstartobevariablewithanirregularperiod; r.v. =+44km/s,and//0"08,HDsp.cl.Na, (B —V)=+1.56,and(U-B)=+1.12;Bus- cl. =B3ne;Cousins,Lake,andStoy(1966)pe.ptm.: (1958) pe.ptm.:F=7.83,(R-F)=-0.14, Keenan andMorgan(1941)saysp.cl.=C5;Vander- (1944) givesr.v.=+44km/s;GCRVquotes (U —B)=0.76;sp.cl.=B2e;hecallsobjectaBe lists individualMt.Wilsonr.v.;CousinsandStoy and Joy(1952)findr.v.=+7.2km/s;Abt(1970) cl. =gKl;Priser(1966)pe.ptm.:F=8.41, and Stoy(1962)pe.ptm.:F=8.40, Wilson andJoy(1952)findr.v.=+58.7km/s;Abt gives 7T=+0"009and//=—0"01,//+0"04; cl. =B8pSi. no. 13withpe.ptm.:F=8.15,(B—V)=—0.13, cl. =B2V{n)(el),M-2.5. Guetter (1968)sp.cl.=B2:Vne;Walbom(1971) [B —V)=-0.20,(U-B)=+1.24;sp. 5276; GCRVgivesr.v.=—11km/s;callsasp.bin.; cl. =B3V;Golson(1970) pe.ptm.F=8.65, cl. =B2V;KennedyandBuscombe (1974)quotesp. GCRV givesr.v.=+6.7km/s;//0"007;Wilson (B —F)=+1.14,(U-B)=+1.13;Buscombe (B-V)= +1.13,(U-B)=+2.20;quotesp. (1970) listsindividualMt.Wilsonr.v.values;Cousins GCRV givesr.v.=+58.2km/sand//0"016;PC (U —B)=+2.52;quotesp.cl. =gM2. (1962) pe.ptm.:F=7.61, (2?—F)=+1.63, 6015; GCgives¡u=+0:007,fi+0'!002; (1980) quotessp.cl.=K0III. (Í7 —2?)=—0.44;Buscombe(1980)quotessp. a 1089; Sanford(1935)saysr.v.=+40km/s; £ F =7.83,(B—V)=0.20,(UB)=0.76; a0 5 a0 v c c c a0 = +0"59,¡li—3"71;Largemotionannounced = —0"040;Buscombe(1977)quotessp.cl.C5,4. s 457 458 A. U. LANDOLT: UBVRI PHOTOMETRIC STANDARDS 458

(B — V) = -0.167,(U-B)= - 0.756; Crawford, HD 140850 = BD - 0°3005; Golson (1970) pe. ptm.: Golson, and Landolt (1971) pe. ptm.: F= 8.633, V = 8.80, {B-V)= +1.661, (U-B)= +2.02; (B-V)= — 0.158, (U — B)= -0.751. Crawford, Golson, and Landolt (1971) pe. ptm.: BD + 1°2447 = PC 2456 = GCRV 6576 = Ci V = 8.813,(i? — V) = + 1-660, (U-B)= +2.004; 20,580 = CC 580; PC gives tt = (n28; Upgren and Staron ( 1970) sp. cl. = K2 III; note object = — 0"60, /i<5=0"75; GCRV gives r.v. = +11 is in Selected Area 107; however, the star is not cata- km/s; Abt (1970) r.v. = + 18.3 km/s; Buscombe logued in HA Vol. 101. (1977) quotes V= 9.63, (B-V)= + 1.52, HD 148817 = BD + 0°3536; Priser (1966) pe. ptm.: [U — B)= + 1.19, sp. cl. = M2.5 V; Eggen (1980) V= 8.32,(B — V) = + 1.48,(U-B)= + 1.78;HD finds pe. ptm.: V = 9.65; [B — V)= + 1.50, sp. cl. = K2. (U-V)= +1.2%,Re = %.50,{R-I)e= +0.96. HD 149382 = BD — 3°3967 = GCRV 9530; GCRV HD 97503 = GC 15419 = BD + 5°2463; GC gives ¡ua r.v. = + 3 km/s, // = 0"017; Neubauer (1943) = — 0"305, /liô = — 0"034, Roman (1955) finds sp. r.v. = + 3.3 km/s; notes r.v, var.?; sp. cl. = B5n. Tr = + 0"066; fia= - 0"293; /i0 = - 0"030; pe. HD 157881 =GC 23592 = BD + 2°3312 = GCRV ptm.: V = 8.73, (B — V) = + 1.17, (U-B) 10069 = PC 3955 - LET 1348 = G19-24; GC gives = + 1.09; sp. cl. = K5 V. ju = - 0"588, ju = - l'!196; PC gives tt = 0:'125, BD + 5°2468; Cowley (1958) found object to be a blue a 0 jua= - 0"587; jus= - l':i96; GCRV gives star, jua = — 0"043, jlls = + 0"012; sp. cl. = B8; r.v. = —28.3 km/s; Adams (1915) r.v. = —27.8 Klemola (1962) found fiacosS = — 0"067, ji0 km/s; Wilson (1967) r.v. = —21.4 km/s; Wilson = — 0"025; sp. cl. = B6; pe. ptm.: V = 9.42, (1962) tt = 0"125, andMu = +8.1; Cowley, Hiltner, (B-V)= -0.14,(U-B)= -0.54. and Witt (1967) sp. cl. = K7 V; Johnson and Harris HD 100340 = BD + 6°2461; Cowley (1958) discovered (1954), an C7BV std. star whose pe. ptm.: F= 7.54, object to be a blue star, fia = — 0"001, [i0 (B—V)= + 1.36, (U — B)= + 1.26; many, many = + 0"008; Klemola (1962) found jua cos Ô references in Blanco et al. (1968). Eggen (1979) pe. = — 0"035, jll8 = +0"01; pe. ptm.: F= 10.19:, ptm.: V = 7.60, (B — V) = + 1.36; (C/-B) (B — V)— - 0.24, [U — B)= - 0.94; Klemola = + 1.25; Re = 6.68, (R — I)E = + 0.60; Cousins notes that the BD right ascension is one hour earlier and Stoy (1963) pe. ptm.: V=7.52, than value given by Cowley; Buscombe (1980) quotes (B- V)= + 1.37; (U — B) = + 1.26. V= 10.13, and sp. cl. = Bl IV-V. HD 160233 = BD + 4°3467 = GCRV 10191; GCRV BD + 5°2529 = PC Suppl. 2703.1 = LTT 13212; PC r.v. = + 3 km/s; noted to be SB; = 0"023; list Suppl, gives 77- = + 0"043, fia = + 0"20; /a0 magn. as 8.6; Neubauer (1943) r.v. = — 24.3 km/s; = — 0"46; Mumford (1956) sp.cl. = K8; pe. ptm.: Petrie and Pearce (1961) note var. r.v., and give ave. V=9.60,(B- F)= + 1.19;8.0; Wilson(1967) r.v. = + 28 km/s; Morgan, Code, and Whitford r.v. = +18.7 km/s, and pe. ptm.: (R—7)c (1955) sp. cl. = Bl V. My photometry indicates a con- = +0.52. Buscombe (1977) quotes V=9.59, stant V magn. over 28 months; does the quoted (B — V) = + 1.24, (C7-B)= + 1.18, sp. cl. = K8 GCRV magn. indicate a possible eclipsing system? V. o BD + 4°3508; Hogg and Kron (1955), their star no. 91; HD 118246 = BD-5 3730; Golson (1970) pe. ptm.: pe. ptm.: V= 9.33, (B — V) = + 1.736, F= 8.07, (B-V)= -0.16, (U-B)= -0.628; (U — B)= + 2.10; quote sp. cl. = K3. Crawford, Golson, and Landolt (1971) pe. ptm.: HD 161961 = BD — 2°4458 = GCRV 10302; GCRV V = 8.062, (B — V) = — 0.158, (U — B)= -0.629; r.v. = —11 km/s; // = 0"032; Sanford and Merrill Buscombe (1980) quotes V = 8.0, (B — V) = — 0.15, (1938) r.v. = —3 km/s; Neubauer (1943) (U — B)-= — 0.61; sp. cl. = B5e; calls it a variable. r.v. = — 13.0 km/s, and sp. cl. = Bisk; Wilson, and BD + 2°2711; Cowley (1958) discovered object to be Joy (1950) r.v. = —6.0 km/s; Guetter (1964) pe. blue; sp. cl. = B8; Klemola (1962) found sp. cl. = B4, ptm.: V = 7.89, (B — V)= + 0.23, (U-B) cos <5 = — 0"003, fi0 = — 0"006; pe. ptm.: = - 0.67; r = 2.47 kpc; sp. cl. = B0.5 III. V = 10.41, [B — V) = -0.17, [U-B)= -0.69. BD + 4°3561 = Barnard’s star = PC 4098 = CC HD 121968 = BD — 2°3766; Cowley (1958) discovered 1069 = Ci20, 1069 = LET 1385 = GL 699 = G140- object to be blue, sp. cl. = B8, /Li = + 0"006, fi a 0 24; PC gives tt = + 0"545 and //a = — 0"72, /ll0 = +0"037; Klemola (1962) found sp. cl. = B0; = + 10"27; Adams and Joy (1923) r.v. = — 107 [ia cos 5 = + 0"004, fi8 = +0"049; pe. ptm.: km/s; Munch (1944) r.v. = — 111 km/s; Wilson V= 10.31, [B — V)= -0.19, (U-B)= -0.89. (1967) r.v. = — 106.6 km/s; Johnson and Morgan HD 129975 = BD + 0°3234; Golson (1970) pe. ptm.: (1953) sp. cl. = M5 V; an UBV std. star, pe. ptm.: V— 8.37, [B-V)= + 1.496, {U-B)= + 1.856; V = 9.54, (2? — V) = + 1.74,(U-B)= + 1.29; Eg- Crawford, Golson, and Landolt (1971) pe. ptm.: gen (1979) pe. ptm.: V= 9.54, (B — V) = + 1.57 (5 V = 8.363, (B — V) = + 1.501, (U-B)= + 1.845; and 7 transposed?), (U — B)= + 1.30, RE = 8.09, Buscombe (1980) quotes sp. cl. = K3 III. (R-I)e= +1.26.

© American Astronomical Society • Provided by the NASA Astrophysics Data System 459 A. U. LANDOLT: UBVRI PHOTOMETRIC STANDARDS 459

HD 170493 = BD - 1°3500 = PC 4254 = GCRV HD 196395 = BD- 1°4014; Golson (1970) pe. ptm.: 10958 = C 2425 = Ci 18, 2425; PC gives F= 8.72, (B-F)= + 1.659, (Î/-B)= +2.043; ir= +0"051 and //« = +0''14, [is= — 0"21; Crawford, Golson, and Landolt (1971) pe. ptm.: GCRV gives r.v. = — 53.3 km/s; Wilson and Joy F= 8.722, (B-F)= + 1.653, and (1950) r.v. = — 52.8 km/s; Johnson and Knuckles (C/-B)= +2.043. (1957) pe. ptm.: F = 8.05, [B — V)= + 1.10, HD 196573 = BD + 0°4558; Priser (1966) pe. ptm.: (U —B) = + 1.06; sp. cl. = K5; Nikonov cia/. (1957) F = 7.87,(B — F) = + 1.65,(Í/-B)= + 1.99; HD pe. ptm.: F= 8.05, (B-V)= + 1.09; sp. cl. = dK4; sp. cl. = K5. Buscombe (1977) quotes sp. cl. = K5 V. HD 199280 = HR 8014 = GC29212 = BD - 4°5307; o HD 173637 = BD - 8 4702 = GCRV 11220; GCRV GC gives //a = + 0"022, /+ = + 0"020; r.v. = — 46 km/s; and /x = 0"022; Neubauer (1943) r.v. = — 29.2 km/s; Cowley et al. (1969) sp. cl. = B8 r.v. = — 46 km/s; sp. cl. = BOe, note says “almost Vn; Cousins (1962) pe. ptm.: F=6.56, continuous” spectrum; Morgan, Code, and Whitford (B-F)= -0.10, (i/-B)= -0.28; Crawford (1955) sp. cl. = Bl IV; Hiltner and Iriate (1955) pe. (1963) pe. ptm.: (B — F) = —0.08, ptm.: V = 9.35, (B - F) = + 0.28, (U — B) = — 0.33; H/?= + 2.787; also see Hoffleit (U-B)= -0.66; A/= - 3.2; (m-M) = 10.9. (1982), where some quoted values differ slightly. HD 175544 = BD + 0°4055 = GCRV 11377; GCRV HD 200340 = HR 8054 - GC 29377 = BD - 1°4095; gives r.v. = — 4 km/s, and notes that star is a dbl. GC gives /i„ = + 0"003, fia = O'.'OOO; r.v. = — 11.8 line SB; fi = 0"036; Neubauer (1943) r.v. = -4.1 km/s, var. vel.; Kennedy and Buscombe (1974) quote km/s; Petrie and Pearce (1961) ave. r.v. = — 16 km/ sp. cl. = B6 V from Cowley et al. (1969), but I could s; Thackeray and Tatum (1966) ave. r.v. = — 12.9 not verify; Crawford (1963) pe. ptm.: km/s, with orbital solution, P = ld98575; Hiltner (B-F)= -0.10, (C/-B)= -0.47, Mß (1956) sp. cl. = B3 V; pt. ptm. F = 7.35, = +2.700; Cousins (1964) pe. ptm.: F =6.49, (B — V)= +0.10, (U — B) = -0.64; M= - 1.5; (B — F) = — 0.10, (U — B)= - 0.48; also see Hof- \m—M) = 8.0; also gave polarization measures. fleit (1982), where some quoted values differ slightly. HD 184914 = BD-4°4855; Golson (1970) pe. ptm. HD 205556 = BD + 4°4703; Golson (1970) pe. ptm.: F = 8.16, (B — V)= + 1.197, [U-B)= +0.927; F =8.32, (B — F) = -0.058, (U-B)= -0.354; HD sp. cl. = K5; Crawford, Golson, and Landolt HD sp. cl. = B9; Crawford, Golson, and Landolt (1971) pe. ptm.: F = 8.168, (B - F) = + 1.194, (1971) pe. ptm.: F= 8.318, (B - F) =-0.057, [U — B) = +0.935. (U — B) = -0.362. HD 188934 = - 0°3883 = GCRV 12300; GCRV HD 209796 = BD + 0°4820; Golson (1970) pe. ptm.: r.v. = + 57 km/s; Sanford (1924, 1935, 1944) F = 8.94, (B- F)= + 1.206, [U-B)= + 1.169; r.v. = + 56.6, + 56, + 57 km/s, respectively; sp. HD sp. cl. = K2; Crawford, Golson, and Landolt cl. = R3in(1924)andR4in(1944); Vandervort(1958) (1971) pe. ptm.: F = 8.934, (B - F) = + 1.208, r.v. = +57 km/s; /¿a = — 0"008, = — 07013; [U — B) = + 1.161. sp. cl. = R8; pe. ptm.: F = 9.31, (B — F) = + 2.06; HD 210894 = BD - 5°5735; Sanders (1966) star 2220- Mendoza and Johnson (1965) pe. ptm.: F= 9.37, 5, no. 6; pe. ptm.: F=9.14, (B - F) = +1.35, (B-F)= +2.01, [U — B ) = + 2.10, (U-B)= + 1.41; HD sp. cl. = K2. ([/_ F)= +4.11, (F-B)= +1.40, HD 216135 = BD - 14°6357 = F }07; Cowley (1958) (F-/)= +2.37, (V — J) = + 3.16, discovered star to be blue, sp. cl. = B8; Feige (1958) (V-K)= +4.22, (F-L)= +4.11; sp. cl. = R8; also found blue nature of star, and provided chart B.C. = - 1.54, Te = 3390 K; diameter = 0:'0007; (Feige, 1959); Klemola (1962) found fin cos <5 recall that the just quoted colors are Johnson colors, = — 0"020, pg = — 0"016; sp. cl. = B3; pe. ptm.: not Cousin-Kron as in Table IV in this paper. F= 10.13, (B-F)= — 0.13, (U — B) = -0.59. HD 191639 = HR 7709 = GC 27998 BD + 1°4774 = GC 33053 = PC 5763 = Ci 18, 3124 = BD - 9°5382 = GCRV 12530; GC gives /na = GL 908 = G29-68 = LFT 1828 = Y 20 - 8164 = + 0"003, ns = 0"000; GCRV gives r.v. = - 7 = Ci 20 - 1454 + ; GC gives //* = + 0:'980, km/s; Plaskett and Pearce (1931) r.v. = — 7.2 km/s; ps = — 0"962; PC gives tt = + 0"160; Johnson and Morgan, Code, and Whitford (1955) sp. cl. = Bl V; Morgan (1953): an UBVstd. star; sp. cl. = M2 V; pe. Cousins(1964)pe.ptm.: F = 6.48, (B — F) = — 0.16, ptm.: F = 8.98, (B-F)= +1.48 (U-B) (U—B)= —0.92; Lesh (1968), distance = 863 pc; = + 1.09; Wilson (1967) r.v. = - 65.3 km/s; Bus- Hoffleit (1982): notes on p. 434 say star is var., with combe (1977) quotes sp. cl. = M2 V e; Eggen (1979) amplitude 0.3V, 0.09U, 16.82 day period; magnetic pe. ptm.: F= 8.98, (B-F)= +1.50, variable. (£/ —B) = + 1.08, B£ = 7.94, (B — / >£ = +0.865.

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