1 Halley’s Comet as depicted in the Tripartitum Psalter Eadwini (The Canterbury Salter cir.1150 acknowledgements to Trinity College Cambridge, (licensed under Creative Commons) 1 THE COMET’S TALE Comet Section – British Astronomical Association Journal – Number 36 2017 October britastro.org/comet In memoriam - C/1995 01 1997 March 08 0355-0453 1.2m f.1 f/7 Zeiss Triplet 10”x8” hyperred 4415- Glyn Marsh
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Halley’sCometasdepictedintheTripartitumPsalterEadwini(TheCanterburySaltercir.1150acknowledgementstoTrinityCollegeCambridge,(licensedunderCreativeCommons)1
THECOMET’STALECometSection–BritishAstronomicalAssociation
Journal–Number362017October
britastro.org/comet
In memoriam - C/1995 01 1997 March 08 0355-0453 1.2m f.1 f/7 Zeiss Triplet 10”x8” hyperred 4415- Glyn Marsh
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TableofContents
Contents Author Page1 Director’s
WelcomeNickJamesSectionDirector
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2 ObituaryforDr.GlynMarsh
DenisBuczynskiSecretary
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3 InterviewwithJJGonzalez
ClaudioPraforCeieliDolomiti
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4 TeamWorking–DiscoveryofFragmentComet
ErikBryssinckandJoschHambsch
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5 Confessionsofanon-scientificCometObserver
OwenBrazell 16
6 ObservingHalleyfromTenerife
RichardJones 21
7 FromtheArchives
NickJamesSectionDirector
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8 Comet38PStephenOterma
DenisBuczynskiSecretary
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9 MemoriesofCometHondaMrkos-Pajusakova
P.ClaySherrod 32
10 Editor’sWhimsyTheCometStone
JaniceMcCleanEditor
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11 Contacts 3812 PictureGallery Pleasenotethatcopyrightofallimages
belongswiththeObserver 39
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1 FromtheDirector–NickJames
IthasbeenawhilesincethelastissueoftheComet’sTalebutthatisentirelymyfaultandIhopethatitwillappearmoreregularlyinthefuture.Ournewslettereditor,JaniceMcClean,hasdoneanexcellentjobonthiseditionandIhopeyouallenjoyreadingit.Iwouldalsoliketothankthemembersofthesectioncommitteeandallourobserversfortheirsupportduringthesession.
Therehavebeennoparticularlybrightcometsvisiblethisyearbutafewrosetonearnaked-eyevisibility.Amongthesewerethereturnsofperiodiccomets2P/Encke,41P/Tuttle-Giacobini-Kresakand45P/Honda-Mrkos-Pajdusakova,theunexpectedlybrightC/2015ER61(PANSTARRS)andtheshort-livednewdiscoveryC/2017E4(Lovejoy).ThemostobservedobjectwasC/2015V2(Johnson)whichreachedperihelionin2017Junebutwhichwaswellplacedthroughoutmuchofthewinterandspringandwhichreached8thmagnitudeinMay.Inadditiontothesebrighterobjectsourobservershavekeptmanyothercometsunderobservationandoutburstshavebeendetectedinanumberofobjectsincludingtheperenniallyactive29P/Schwassmann–Wachmann.RichardMilescontinuestoleadour29Pmonitoringprojectand,asthecometcomesnorth,heisgearingupforanincreaseinobservations.
DenisBuczynskicontinuestomanageourSection’sonlineimagearchive.Atthelastcount,thisarchivenowstandsatatotalof17,713images.Ofthese3,146imageswereaddedinthelastyearandatotalof189
cometswereimagedordrawnbycontributors.Imageswereincludedfromatotalof85differentobserverswiththemostprolificbeing:AlfonsDiepvens(627),PeterCarson(478),ErikBryssinck(439),MikeOlason(336),AlexanderBaranski(246),DenisBuczynski(240),NickJames(105)andTonyAngel(78).Thearchiveisavailablehere:
http://www.britastro.org/cometobs/
WehadasuccessfulsectionmeetinginNorthamptononJune17andareportofthishasappearedintheAugustJournal.Themeetingwaswellattendedanditcoveredawiderangeofsubjects.ItwasalsoourfirstmeetingtomakeuseofSkypetoallowaspeaker(PadmaYanamandra-Fisher)topresentatalkfromthewestcoastoftheUS.Themeetingwasrecordedalthoughwehadsomeproblemswithrecordingequipmentwhichhasslowedprogressongettingitemsuploaded.Mostofthetalksarenowavailableonlinehere:
https://www.youtube.com/playlist?list=PLzBTybazXT40groFEC3zg4uVLFFGdApQL
WeplantoholdthenextmeetingintheSpringof2019.Moredetailswillbedistributedassoonaswehavethem.Iknowthatitiscurrentlyalongwayoffbutifyouhaveanyideasregardingtopicsforinclusionpleaseletmeknow.
Ihavenowtakenoverthesectionhard-copyarchivefromJonathanShanklin.MostofthiswastransferredinaNorthamptoncarparkafterthesectionmeetinganditfilledmostofthespaceinmyMondeo!We
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havestartedtoindexandscanthematerialandsomeofthishasalreadybeenuploadedtotheCometSectionwebsite.Thearchivecontainsmanyoldcometphotosanddrawingswhichwillgraduallybemadeavailableonlineoverthecomingyear.
Between1973Februaryand1987February,theCometSectionproduced26issuesofaNewslettercalledIstimirantStella.ThesewereeditedbyMikeHendrie,AndyStephensandStanMilbourn.Alloftheseissuesarenowavailablehere:
https://britastro.org/node/10769
Itisaninterestingreadandshowshowdifferentthingswere40yearsago.LookoutforJohnBortle'sguidetocomethuntinganddescriptionsofCometWestfrom1975alongwithmanyotherinterestingnotesandobservations.Therearequiteafewfamiliarnamesintheseissues.
Cometobservations(bothvisualandelectronic)continuetobesubmittedviatheonlineCometObservationsdatabase(COBS),althoughmanyobservationsaresentdirectlytothevisualobservationsco-ordinator,JonathanShanklin.Jonathanhascontinuedtoanalysequantitativedatasubmittedbyvisualandnow,increasingly,CCDobservers.HereformatstheobservationsintotheformatthatGuyHurstusesforpublicationinTheAstronomer.Jonathanalsomaintainshishighlyinformativecometobservationsandanalysiswebsiteandhasagainassistedmebyprovidingthecometmaterialforthe2018Handbookandthecometprospects.
AcompletelyrevisedversionoftheCometObservingGuidewasreleasedearlierthis
year.I'dliketothankthesectioncommitteewhohavehelpedmewiththistaskandIhopethatthenewversionwillbeofusetobothnoviceandadvancedobservers.Ourintentionistokeepthisuptodatewithfairlyregularupdates.YoucanfindtheGuidehere:
https://britastro.org/node/6817
Pleaseletmeknowifyouspotanyerrorsorfeelthatweshouldincludeinformationonothertopics.
TheSectionhascontinuedtodevelopthecomphotcometphotometrysoftwareandtestingcontinueswithanumberofobservers.ThelatestversionaddstheabilitytoproduceICQformattedoutputrecordswhichshouldsimplifythesubmissionofdatatoCOBS.Youcandownloadthelatestversionfrom:
https://britastro.org/node/11124
IfyouareanewuserofcomphotpleasecontactmebeforesubmittinganydatatoCOBS.
RogerDymock,ouroutreachandmentoringcoordinatorhasaskedtostepdownfromthatrolesincehewantstoconcentrateonexoplanetwork.IwouldliketothankRogerforthesupporthehasgivenmeoverthepastfewyears.HehasbeenoneofthefewpeoplefromtheSectionwhohasbeensubmittingtotalcometmagnitudesestimatedusingimagesfromremotetelescopes.ThisisacomplexanddifficultsubjectandRogerisoneofthefewpeoplewhohavetakenthison,helpingotherswithhisknowledge.
RogeralsomaintainedtheProjectAlcockwebsitewhichcontainednotesandguides
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onmanydifferentaspectsofpracticalcometobservingandimaging.ThissiteisnolongeractivebutIhope,withRoger'sagreement,tomovesomeofthearticlestothemaincometsectionwebsiteoverthenextfewmonths.
I'msurethatweallwishRogerwellwithhisexoplanetworkandhopethatcometswillstillbeonhistargetlisteverynowandagain.Ifanyonewouldliketotakeuptheoutreachandmentoringrolepleasecontactmedirectly.
Asyouwillhaveseenfromthefrontcover,mygreatfriendandcometobserverGlynMarshdiedsuddenlyinAugust.IheardthenewsfromDenisBuczynskiwhileIwasintheUSfortheeclipseandfounditverydifficulttobelieve.Glynwasagreatpersonalfriendandaveryaccomplishedobserver.IremembermyvisitstoPrestonand,morerecently,theIsleofManwhereGlynandChristinealwaysmademefeelverywelcome.ManywillalsorememberGlyn'sdemonstrationofhowtomakeacometgivenatthesectionmeetingin2015.HewassodedicatedtothetaskthatheevenboughtasmallcampingfridgetokeepthenucleuscoldonitsjourneyfromtheIsleofMan.In1996GlynwasinstrumentalinthesuccessofatripthatMartin
Mobberley,GlynandmyselfarrangedtoobserveC/1996B2(Hyakutake)fromtheclearskiesofMt.Teide,Tenerifeandhehelpedmeinmanyareassincethen.Iwillreallymisshimasafriendandasanobserver,asIamsuredoallthatknewhim.
ItisalsosadtoreportthatouronlylivingBritishvisualcometdiscoverer,RoyPanther,diedinOctober2016.RoywasthediscovererofcometC/1980Y2(1980u).Thediscoverywasmadevisuallyusinga0.20m,f/4Newtonianat1850UTonChristmasday1980whenthecometwasa9thmagnitudeobjectnearM56.ThediscoverywasconfirmedthateveningbyMikeHendrieandGeorgeAlcockanditwasRoy'sfirstsuccessafter601hoursofsearching.
Letushopethatsoonwehaveanewcometintheskythatwecanallobserveandindoingsopayourrespectstothesetwogreatobservers.
NickJames–SectionDirector
2 ObituaryforDr.GlynMarsh–DenisBuczynski
OnAugust182017,ourfriendandcolleagueGlynMarshpassedawayattheageof63ontheIsleofMan,hischosen
homeforthepastfewyears.Glynretiredfromhisprofessionalcareerasachemicalcorrosionscientistworkinginthenuclear
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industryforBNFL.He,andhiswifeChristine,movedtotheIsleofMan,primarilytoenjoyamorerelaxedpaceoflifeandtoobservecometsandotherastronomicalobjectsandeventsinthedarkerskiesthere.
Glynwillbelongrememberedasaverymodestbutextremelycapableamateurastronomer,whoobservedwheneverconditionsallowed.Hewillbeparticularlyrememberedforhisexpertiseintelescoperepairandrestoration.Heimmersedhimselfintothefabricoftheastronomicalsocietieshejoined(TheBAA,PrestonandDistrictASandtheIsleofManAS)andwasavaluablecontributingmemberofeach.
Hewasaveterancometobserverandfilmphotographerandheexcelledatthisdifficultskill.HisphotographsofCometHale-BoppandHyakutaketakeninthemid1990’susingastrographlensesandlargeformatfilm(10x8inches)wereamongstthebestandmostdetailedtakenintheUK.
Hewasagreatfriendtoallandfreelyofferedhishelp,adviceandexpertisetoanyonewhoasked.Asaregularattendeeatmeetingshewasalwaystobeseenindeepconversationswithobserversdiscussinginstrumentsandevents.ArecentoutstandingmemoryofhimcameattheBAACometSectionmeetingatNorthamptonin2015wheninfrontofafascinatedaudienceheconstructedacometnucleusfromfrozenrawmaterialswhichshowedstructureandcompositionincludingout-gassing.Anyonewhosawthedemonstrationwillneverforgetit,(includingtheverystrongassociatedsmell).
DrGlynMarshmakinghisfamouscometattheNorthamptonCometSectionMeeting2015
HehadequippedhimselfwithanimpressivepersonalobservatoryathisManxhome.Thiscomprisedofolderinstrumentsaswellasthemostmoderntechnologyandtelescopes.HewasinthemiddleofacompleterestorationofthehistoricMond/Cookeastrographtelescopewhichhehadrescuedfromdestructioninthelate1980’sfromtheNormanLockyerObservatoryinSidmouth.Hehadgenerouslyagreedwiththesameobservatorytoreturntherestoredinstrumenttothemathisowncost.He
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showedthisgenerositytoallwhoaskedandhewillbetrulymissedbyallthegoodfriendshemadeintheastronomicalcommunityoverthe40yearperiodhewasinvolvedwithit.
DenisBuczynski-SecretaryCometSection
3 InterviewwithJuanJoséGonzálezSuárezbyClaudioPra–Expandedversion,from‘CieliDolomiti’bykindpermissionoftheinterviewee.
JJGonzalezdescendinganiceholeintheJouNegroGlacierinPicosEuropa1995
Icannotrememberatwhatageastronomybecamealife-longpassion.Iwasbornin1952inAvilés,anhistoricalandbeautifuloldtownrenownedasanindustrialcityandseaportinAsturias,NorthSpain.Asaboy,Igrewupinasemi-ruralenvironment,
withplentyofnaturallandscape,seaandsometimes(weatherpermitting)darkskiesfullofstars.Imademyfirstrudimentarytelescopeandtooksomephotographicimagesofstarsandgalaxiesinthenightsky.Iwasinspiredtobecomeascientist.IchoosePhysics,earningamaster'sdegreeinAstrophysicsatUniversidadComplutense(Madrid)in1976.
Afterfinishingmydegreemyambitionwastobecomeaprofessionalastronomer,inamountainobservatory,butthiswasthenimpossibleinmycountry.Atthattime,thenowfamousgreatobservatoriesofSpainwerenotevenbuilt,sopositionsinprofessionalastronomywerefewandfarbetween.ItookthedecisiontoreturnhomeandworkasaphysicsteacherinAsturias,surroundedbymyhighmountainsunderaclearnightsky.InthenextfortyyearsIdedicatedmylifetomymainpassions;astronomy,physics,andAsturias'mountain-relatedstudies(karsticcaves-speleology,andglaciology).NowallIneedaremymountainsforfeelingalive
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andobservingcomets,forfeelingthescienceofthenightskyinmyblood.
CantabrianMountainsinthesunrise
1)Whatledyoutoobservecometsandhowmuchtimedoyoudedicatetothispassion?
Cometsareintrinsicallyofmajorscientificimportance.AsDanGreensaid,"observationsofcometsbyamateursareessentialtotheprogressofcometaryastronomy".FredWhipplesaid,"observingcometshasbroadeffectsinscience,besidesgivingtheobserverpersonalpleasure".Forme,thispleasureincreasesgreatlywhenvisuallyobservingfromtheCantabrianMountainsinmyhomeland.Highmountainsandcometshaveinterestingaspectsincommon.Somemountaintopsarethebestplacesforobserving.Theicethatfeedsthemountainglaciersisalsopresentinthenucleusofcomets.Thecometaryicethatorbitsintheblacknessofspacealsosleepsinsidethedarkdepthsofmountaincaves.Wecanenjoyourselves,observingthecometsfrommountains,andwecanalsostudytheice.Iobserveeveryavailableclearnight,weatherpermitting.Inafruitfulyear,2010,Iobservedapproximately50nights.
2)DoyoufeelsurpassedbymodernCCDtechnologywhenmakingvisualestimates?
Notatall.CCDandvisualdataarecomplementary,notexclusive.Wecontinuealongobservingtradition,addingourdatatothehistoricalrecords.Iamanold-stylecometobserver,tryingtomaketheobservationsinthebestpossibleway,underthebestavailableconditions,
providingusefuldata.Iworkhardlookingforhigherandbetterobservingsites,tryingtoobserveasmuchcomadiameteraspossible,especiallyforverygaseouscometswithlowDC.DanGreensaid,“thehumaneyeisaremarkabledetector,superiortoanyartificiallight-detectioninstrumentintermsofdynamicrangeofspectrumandlightintensitycombined".
3)Forhowlongaperioddoyouusuallyobserve?
Thedurationofanobservingsessiondependsonseveralfactors,suchasthephaseoftheMoon,weather,distanceIneedtotraveletc.Atypicalobservingsessioninvolvespriorhomepreparationofchartsforeachobservablecometwithsuitablecomparisonstarswithgoodphotometry(Tycho-2,APASS,)thencheckingthestar-fieldintheDSSimages(especiallyforthefaintcomets),consultingweatherforecastsandMeteosatimages,andchoosingtheobservingsite.ThenIusuallyspendonetothreehoursofroundtriptravelbycar(100-300km).Iobserveduringalltheavailabledarkhours.ThenthereisthetimespentafterwardsreducingthedataandsendingtotheICQandothersites.Mymost"profitable"sessionwasthenightfrom21.86to22.20UTMarch2009,whenIcouldobserveandestimate20comets.
4)Whichbinocularsandtelescopedoyouuse?
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Besidestheclassicalbinoculars;7x50,10x50,11x80and25x100,forthebrightercomets,myworkhorseisa20cmMeadeSCTLX-200GPS.Itisagoodcompromisebetweenapertureandweightformountainobservingsessions.Asarule,toobserveasmuchcomadiameteraspossible,itisimportanttoworkatlowmagnification(normally50to150x)withthetelescope.
JJGonzalezplus20cmSCTinthemorninglightatPuertoAralia--1530metreshigh
5)Yourobservingsiteseemstobenearideal.Canyougiveusadescription?
Iworkhardlookingforthehighestandbestobservingsites.MylocalknowledgeoftheCantabrianmountains(AsturiasandLeon)helpsmetoseekthebestlocationsforatmosphericconditionseachsession.TheCordilleraculminatesinaruggedkarstmassif,LosPicosdeEuropa,at2651m.Ihaveobservedfrom2500minPicos,butthenormalsitesaccessiblebyroadarelocatedbelow2000m.
InAsturias,onthenorthernslopeoftherange,theweatherisnormallycloudy.Besides,wehavealightpollutionproblemintheheavilypopulatedcentralareawith800,000inhabitants.MainlyIseekthebetterweatheronthesouthernslopeoftherangeatLeon,wheretheAltodelCastroislocatedat1720m.Ithaswithanear360-degreeunobstructedhorizonandasummitaccessiblebyanarrowroadwhensnow-free,normallybetweenAprilandNovember.Itspositionnearthedividingrangeprovidesadarkandveryclearsky
downtothehorizon,especiallytotheeastandwestalongthedirectionoftheridge,veryusefulfortwilightobservations.
Dependingontheweather,Iuseothergoodmountainobservingsitesinthe1000-1800mrange.
6)Haveyouattemptedthediscoveryofanewcomet?
Thesearchfornewcometsisnotapriorityforme.Icanonlydedicatealittletimetoitbeforethemorningtwilight,afterfinishinganobservingsession.Mymainworkistoprovideasgooddataaspossibleoftheobservablecomets.
7)Canyoutellussomeinterestingfactsaboutcometobservationsthathaveimpressedyou?
Firstly-CometBarnard.Itwasdiscoveredin1889bytheinspiringandlegendaryvisualobserverEdwardEmersonBarnard.Thefirstellipticalorbitprovidedanorbitalperiodof128years.In1972MarsdenandSekaninacomputedarevisedorbitgivingtheperiodas145±10years.ThiscometwasaccidentallyrecoveredinCCDimagesoftheLINEARprojecton2006June23,becoming177P/Barnard,forwhichMarsdendeterminedaperiodcloseto120years.Imadeoneofthefirstvisualobservationsfollowingrecovery:
2006July7.07UT:m1=13.2,Dia.=0.7',DC=3,20cmSCT(133x)(AltodelCastro,1720m,Leon,SpainMountainlocation,veryclearsky.Limitingstellarmagnitude:15.5.Motioncheckedduringa60-minperiod.ComparisonstarstakenfromHendenphotometrynearRYSer.
Thisshortreportcan'texpressmyemotionalfeelingswhenobservingintheeyepiecethesameobjectthatBarnardobservedacenturyago.2
Secondly-C/2006P1(McNaught):From2006Octoberto2007January,Idevotedmuchtimeandefforttothefollow-upof
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thisgreatcomet.Thesearemylasttwonakedeyeobservations:
2007Jan.12.73UT(dayofperihelion):m1=-3.2:*,DC=9,Tail:1deg.inPA35deg,nakedeye(AltodelCastro,1720m,Leon,Spain)25x100B:Dia.=0.7',DC=8/.Mountainlocation,veryclearsky.Strongzodiacallightvisibleaftertheendoftwilight.MagnitudeestimatecorrectedforatmosphericextinctionwithICQwintertable(comparisonobject:Venus).Alt.3deg.Solarelongation:7deg.Thecometremainedvisiblefor35minutesuntilitset.
Jan.14.71UT:m1=-6:*,DC=8,Tail:1.5deg.inPA50deg,nakedeyeColunga,alt.20m,Asturias,N.Spain.Cometobservedfromnearsealevel,justbeforesunset;magnitudeestimatecorrectedforatmosphericextinction.
Again,myshortreportofJan.14cannotexpresstheemotioninvolved.InKronk'swords,"ThecometwasatitsbrightestonJanuary13and14.Observerstypicallyestimatedthebrightnessas-5to-6andmanywereabletoeasilyspotthecometinbroaddaylightjustbyblockingthesunwiththeirhand".Butveryunfortunately,intheCantabrianMountainswehadhighcloudsonJanuary13and14.
OnthemorningofJan.14,aftercheckingMeteosatimages,ItookthedecisiontotravelbycaralongthevalleysandmountainpassesoftheCordillera,seekinganyavailablewindowinthecloudsthatcouldallowmetoobserveC/2006P1neartheSun.
Finally,after500km,Igaveup.Thecloudsweresolid.Sometimebeforesunset,Iwascomingbackhomealongthecoastalhighway,lookingquietlyatthewesthorizon.Andthen,suddenlyandunexpectedly,thecloudsletmeseethecometbeforesunset.Itwasasuperbvision.Iwasshockedandspeechlessforsometime!
Quickly,Ileftthehighwayandmadeavisualmagnitudeestimate:-6.Afterthisveryspecialday,thecometmovedintotheskiesoftheSouthernHemisphere,butthespectaclewasn'tfinishedyetforusnorthernobserverssince,unexpectedly,wecouldseetheendoftheenormousdustytaileventhoughtheheadwasbelowthehorizon:
Jan.19.79UT:Tailobservation:Severalstriaewereobservedwithnakedeyeaftertheendofeveningnauticaltwilight,betweenJan.19.77and19.84UT,extendingupintotheconeofzodiacallight.Attheendofastronomicaltwilight(Jan.19.79)fourbrighteststriaewereclearlyvisiblebetweenPA20degandPA50deg,measuringabout0.5to1deginwidth,thelongeronespanningmorethan22degupfromthehorizoninPA30deg.(AltodelCastro,1720m,Leon,Spain)
(moredetailsonC/2006P1athttp://www.cometography.com/lcomets/2006p1.html).
Myusualobservingsite–AltodelCastroat1720m.justaftersunrise
8)YouwerethefirsttoidentifytheremainsofC/2010X1(Elenin)post-perihelion,atatimewhenCCDimagesdidnotregisteranything,butsubsequentlytheyconfirmedyourobservation.Whatareyourimpressionsaboutthisexperience?
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Thereweretwoindependentandnearlysimultaneousvisualobservations,fromMieczyslawParadowskiinPolandandmyself:
LikelyremnantofCometC2010X1Elenin.Data22/10/2011from07:35UTNewMexicowithsystemagras020RLigustri.(CAST)Italy,apo106/530ccdSTL8300C6x300secfield116’x87’
C/2010X1:
2011Oct.9.13UT:m1=12.0,Dia.=2.8',DC=1,20cmreflector(71x),MieczyslawParadowski,Dabrowa,Poland.Cometalt.22deg.NearbyfieldstarscheckedinDSS.
2011Oct.9.20UT:m1=10.7,Dia.=6',DC=1/,Tail:0.2deg.inPA310deg,20cmSCT(77x),JuanJoseGonzalez(AltodelCastro,alt.1720m.,Leon,N.Spain).Thecomaappearslargeandverydiffuse,withoutcentralcondensation.Observationmadefrommountainlocationunderverygoodseeingconditions.NearbyfieldstarscheckedinDSS.Zodiacallight.Altitude:23deg.
Imadetwomoreobservations,onOct.21andOct.30,givingcomplementarydata:
Oct.21.00UT:m1=10.2,Dia.=7',DC=1/,Tail:0.4deg.inPA310deg,20cmSCT(77x),JuanJoseGonzalez(AltodelCastro,alt.1720m.)Thecomet'sremnantappearsvisuallylikeaverydiffusetail-likemorphology,observablefor0.4degalongthemajoraxis,showingtwonear-circularareasofsimilarbrightnesswithaslightlyhigherdegreeofcondensationand7'ofdiameter.Oneoftheseareas,withgeometriccentrelocated
approximatelyatR.A.=8h00m.5,Decl.=+28o26'.0(Oct.21.00UT),wasclosetotheephemerisposition.Theotherarea'scentrewaslocatedatR.A.=7h59m.5,Decl.=+28o34'.5.Themotionofbothareaswasfollowedfor40minutes,beingconsistentwiththeephemeris.Observationmadebeforemoonrise,frommountainlocationwithverygoodseeing,underslightlybetterconditionsthantwelvedaysago(Oct.9).NearbyfieldstarscheckedinDSS.Altitude:16deg.
ThefirstCCDimagescamefromGiovanniSostero,ErnestoGuidoandNickHowesonOct.21.38UT.
FromCBET2876:"...TheamountofthedustejectainthecloudofC/2010X1cannotbedeterminedbecauseofthelackofphotometry.Averycrudeestimateofthetotalcross-sectionalareaofthedustparticlesisonlyprovidedbythevisualmagnitude10.2thatwasestimatedbyJ.J.GonzalezonOct.21;theresultisabout480km2.Themassofthecloudcomesouttobeontheorderof1012grams."
Betweenthefirstdateobservingdate,Oct.9andNov.6,thereweremorevisualconfirmationsandCCDimagesofthecomet'sremnantbutgreatdebatestookplaceontheinternationalmailinglistComets-mlinwhichIhavebeendirectlyinvolved.
Therehavebeensomescepticalandexperiencedpeopleonbothsides,visualandnonvisual(CCD)observers,butthemainquestion(positivevisualobservationsoftheremnant)seemssettlednow.Asanillustration;aftersomenegativeattempts,theinitiallyveryscepticalbutexperiencedAlanHalecouldobservetheremnantonthelastdaysofOctoberandfirstdaysofNovember,postingsomecommentsonhissiteandComets-ml:
"OverthispastweekIhavesuccessfullyobtainedthreeobservationsofthe
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remnantduststreamofthiscomet,butthisisextremelyfaint,appearingasnothingmorethanaslightbrighteningofthebackgroundsky;thesehavebeensomeofthemostdifficultcometaryobservationsIhaveevermade.”
ThisC/2010X1"conflict"shouldteachusallsomeimportantconclusions,dependingonourinitialpositiontowardstheissue.Frommyownperspective,theexperienceanddebatehasbeenverypositive,clarifyingtheimportanceofvisualobservations.CCDandvisualdataarecomplementary,notexclusive.
(Aninterestingrecentscientificpaperis,DISAPPEARANCEOFCOMETC/2010X1(ELENIN)...",JingLiandDavidJewitt,2015TheAstronomicalJournal,Volume149,Number4,in:
http://iopscience.iop.org/article/10.1088/0004-6256/149/4/133/meta)
Last,mycometarywebsite:
www.perihelio.org
(Thesearebusytimes,andIcan'tupdatethesiteasIwouldlike...).
JuanJoséGonzálezSuárez
4 Teamworking:DiscoveryoffragmentofcometC/2015ER61(PANSTARRS)-ErikBryssinckandFranz-Josef(Josch)Hambsch
Brightcometsarebeautifulobjectsforbothvisualobserversandastrophotographers.Theyrewardtheobserverwiththeirunpredictablemagnitudes,butthisalsocausesdifficulties.Thenthereistheexcitementofpossiblywitnessingasplitofthecometnucleus.JoschHambschandIrecentlysawasplitasfirstobservers.WeusedJosch'sRemoteObservatoryAtacamaDesert(ROAD)nearSanPedrodeAtacamainChile.Mainlyweselectcometswhereweexpectmagnitudefluctuations,cometsthatpasstheEarthandcometsthatshowasuddenbrightnessjump.Oneofthe
reasonsforabrightnessjumpmaybethesplittingofthecometintotwoormoreparts.Wedecidedtofollowthe73Pcometthisyear,whichpreviouslyhasbeendetectedsplitting.UnfortunatelyitbecametooweakforJosch'ssetup,soinsteadweselectedtheC/2015ER61(PANSTARRS)cometashavingthebestpotential.Thiscometsubsequentlyshowedamagnitudejumpofnolessthan2magnitudeson2017April4.
CometC/2015ER61(PANSTARRS)wasdiscoveredon2015March15,bythe
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PANSTARRS1telescope.Initiallycataloguedasanasteroid,ithadamagnitudeof21.5whilstatadistanceof8.44astronomicalunitsfromthesun.By2016January,thisasteroidwasmagnitude20.By2016February1,CBETNo.4249reportedthattypicalcometpropertieswereobservedforthisobjectforseveralweeks.On2016March28,theasteroidapproachedneartoJupiteratadistanceof0.925astronomicalunits.Thiscloseapproachchangedtheorbitsothattheaphelionmovedinfrom1430AUto~1200AU.By2017January17,magnitude13wasnoted,andby2017April,thisnowcomet-cataloguedobjectreachedmagnitude8.5.OnApril4,JuanJoséGonzálezSuárezwasthefirsttoreportthatbrightnesshadsuddenlyincreasedby>1magnitudeand24hourslateritwasobservedatmagnitude6.5.Withsuchasuddenbrightnessjump,itisnotalwayspossibletofindoutwhatwasthecause.Itmaybeakindoferuptionoftrappedvolatilegases.Duetothetemperaturerise,theinternalpressurebecomessohighthatthecrustbreaksoutandsuddenlyejectsgaseslikeageyser,bringingdustandparticlesalongtothecoma.Thesunlightdoestherestandilluminatestheseparticles;thecometthenreflectsmuchmorelightsothatwecanobservethiseruption.
Thisphenomenonwasthereasonwedecidedtofollowthiscometforawhile.AsitisclearalmosteverynightinChile,itispossibletogatherdataonadailybasis.WestartedwithourobservationsonMay17,2017.Whatwasimmediatelynoticeablewiththiscometwasthemoreovalformofthecentralcondensationaroundthecometcore.Difficulttoobserve,butwithsome
digitalprocessingfiltersinthesoftware,thephenomenacanbeenhanced.
OntheimagesofMay29,2017(seebelow)thereappearedtobesomesortofgrowth,closetothecometcore.Thecentralcondensationwasextendedandusingadigitalfilterforcometmorphology(RWM-radialweightedmodel,wethoughtthattherewasafragmentation.Butitwasdifficulttodistinguishfromtheimages.
ThenegativeimageofthecentralcondensationofC/2015ER61
ThesameCentralCondensationbutwithRWMFilter(PicturesMay29,2017)imageinfo(withRWMfilter):Theblackdotinthecenterofthecomaisthephotometriccenter.Highlightthelightpointrightnexttothephotometriccenterapproximatelyat4o'clock
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Butherewassomethinghappening!Wehadtechnicalproblems,andalsosufferedfrominternalreflectionscausedbyVenuswhichwasnearthecometintheskyandwasdisturbingourobservations.Onourrecordingsof13thJune,suddenlyaclearlyvisiblelightblobappeared.Didwehavefragmentation?AstheMinorPlanetCentre(MPC)prescribesonemusthaveatleasttwodaysofobservationsbeforereportinganeworunknownobject.Theremustbeanotherobserverwhoobservesindependently.
CometC/2015ER61onJune13,2017
Weseeherethattheinitialelongatedcentralcondensationshowsadipandthusshowsaninterruption,whichclearlyindicatesafragmentation.Thefragmentwasclearlydiscovered.
CometC/2015ER61profilecross-sectionofthecentralcondensationdirectionofthefragment.Thex-axisshowsthenumberofpixels.Aroundpixel7istheADUmaximumofthecometcore.Aroundpixel16isthemaximumofthefragment.Tocalculatethedistanceinarcseconds:16-7
=9pixelsatapixelresolutionof1.384arc.seconds/pixelofouropticalsystemgivesitadistanceof12.4arcsecondswitha243°positionangle.AllofthesedataImeasuredwithAstroart6.0.Digitalprocessingfiltersarealsoplug-insinAstroart,(developedbythelateMartinoNicoliniwhounfortunatelydiedin2015attheearlyageof54,)
CometC/2015ER61(PANSTARRS)June13,June14andJune16,2017(3xenlarged)
Aftertheseobservationsandconfirmations,itwastimetomakethereportandsendittoCBAT(CentralBureauofAstronomicalTelegrams)andMPC(MinorPlanetCentre).
Fromthecoreandthefragment,theastrometricpositionsweremeasuredasaccuratelyaspossibleusingAstrometrica.Noeasytaskbecausethedistancetothecometcoreisjustover10arcseconds,thefragmentisinthemiddleofthecomettailandismuchweakerthanthecometcore.IteventuallysucceededandIsentanobservationreporttotheMinorPlanetCentre.Nextweneededaconfirmationfromanotherobserver.WecontactedEmmanuelJehin(TRAPPISTtelescopes)andAlainMaury(SpaceObs).BecauseofbadweatherinAustralia,mostofthoseworkingwithremoteiTelescopes.netwerenotablegiveaconfirmation-thecometwasonlyvisiblefromthesouthernhemispherejustbeforesunrise.EmmanuelJehinwastravelingtoLaSillaandParanalinChiletocommissionandfirstlightanewtelescope,butunfortunatelyhealsohadbadweather.Wereceivedafirstpositive
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confirmationfromAlainMauryonJune17th.
Photo:AlainMaury-Spaceobs-Chile
ConfirmationimagebyAlainMauryofSpaceObsinChile.FragmentclearlyvisiblerightbelowthecentralcondensationofthecometC/2015ER61(approximately4hours)atadistanceofapproximately14arcsec.Withthe0.5-mf/5RILAtelescopeandtotalexposureof22min.
Whatarelief!Especiallyaftersomuchexcitementandtension.LateronJune19,wealsoreceivedconfirmationfromEmmanuelJehin,andhecouldnowclearlyseethefragmentwiththeTRAPPISTtelescopeandafurtherconfirmationonJune17withthenewEUROPA1mtelescope.
FragmentC/2015ER61(PANSTARRS)withthe0.6-mTRAPPISTtelescopeinLaSillaonJune19,2017.
Therewas1x60sec.usinganI-bandfilter(photo:EmmanuelJehin)
TheTENAGRAII0.41-mNewtoniantelescope(MPCstation926)alsodetectedthisfragmenton2017June18.TenagraObservatoriesisacommercialorganisationthatleasestelescopetimetouniversities,astronomersandamateurastronomers.AnMPEC2017-M09:COMETC/2015ER61-B(PANSTARRS)waspublishedpromptlyafterthisindependentconfirmation(thefirst11positionsareourobservations).OnJune24,aCBET4409wasissuedwiththeofficialrecognitionoffragmentC/2015ER61(PANSTARRS)anditwasnamedC/2015ER61-b(PANSTARRS).
Suchexcitingdays!Icannotdescribehowinterestingandbeautifulitwastofollowthisevolution.Cometsareandremainforme,wonderfulobjectstoobserve,andthereisalwayssomethingnewtoexperience.Itwasalsoespeciallyrewardingthatwewerethefirsttoobservethisfragment.AniceanecdoteisthefactthattheconfirmationimagewastakenbyAlainMaurywiththenew0.5-mf/5RilatelescopeofJoschHambsch(BE)andKarelTeuwen(BE),whichisstillinconstruction.WhethertheperceivederuptionofApril4istherootcauseofthefragmentationisstillbeinginvestigated.Presumably,thereasonisduetothegravityinteractionwithJupiterandthesubsequentorbitchange,butmorelikelybytheapproachofthesunaftertheorbitchange.Butweleavethismysterytothespecialists.Differentastrometricmeasurementsarerequiredtoaccuratelycapturethebeginningofthefragmentation.Aninterestingsubjectforprofessionalastronomers.
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TheAuthors:
ErikBryssinck,Kruibeke,Belgium-http://www.astronomie.be/erik.bryssinckFranz-JosefHambsch,Mol,Belgium-principallyavariablestarobserverforAAVSO
ErikBryssinck
5 Confessionsofanon-scientificCometobserver-OwenBrazell
20inchicedupafteranightsworklookingforCometsinDevon
Despitehavingobservedcometsforover40yearsIhavealwayslookedatthemforthepurposesofpleasureratherthanscience.ThatmaybeahereticalthingtosayinanorganisationsofocusedonscienceastheBAA,howevertimeandotherconsiderationshavemeantthatIneverreallyhadascientificfocuswhendoingmyastronomicalobserving,hencemymaininterestsareindeepskyobserving.Mydrawingskillsarealsoso
poorthatIwasforcedtotakeLatinOLevelratherthanArtsodrawingcometswasnotanoptioneither.HoweverovertimeIhavehadtheopportunitytoobservemanycometsvisuallyusingtelescopesperhapssomewhatlargerthanthenormalrun.
Mycurrenttelescopesarea15”anda22”inchDobsonian.ThemethodoffindingcometshasalsochangedsincemyfirstcometobservationofC/1975hKobayashi-Berger-Milonin1975,huntingwitha2”refactorusingaBAAcircularchartforidentification.TheidentificationandnotificationofcometshasalsochangedrapidlynowandinmostcasesapartfromusingJonathanShanklin’syearlycometroundupintheJournalalmostallinformationoncometsthatIusenowcomesfromtheinternetfromforumssuchascomets-ml.Themethodologyoffindingthemhaschangedaswell.Thedayswhenyoueitherhadtogetanephemerisandthenplotitusingpencilonyourstarchart,orifyouwerereallyadvanced,printouta
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roughcomputerstarchartshowingwhereitwasmeanttohavegone.
Althoughmostcometimagersusecomputerstodrivetheirtelescopestotherequiredlocationthishasnotbeensodesirablewithvisualobservingbecauseitisnotpossibletodarkenscreensfromlaptopsortabletssufficientlytokeepone’seyesdarkadaptioninthefield.ThisisachallengenowwithmanymorepeoplehookinguptheirphonesandtabletstotheirtelescopesusingBluetoothorwirelesstofindthingsusingprogramslikeSkySafariwhichreadscometelementsandallowsonetoplotpositionsanddriveatelescopetothem.TheseallrequiresomekindofWirelessorBluetoothadapteratthetelescopeendtotransmitpositionsfromencoderstothedevice.
The20inchinactioninDevon
TraditionallywhendoingvisualastronomyandatelescopethathadGoTo,onehadtocalculatethepositionofthecometatadesiredtime,usually0UTforthenightinquestionunlessitwasreallyfastmoving,andadditintoyourhandsetorDSC.ThiswasparticularlytrueofolderDSCtypessuchastheSkyCommanderandNGCMax,oranyTangentinstrumentderivedbox.TheSkyCommander,tobefair,allowedyoutouploadpositionstoauserareabutitwasclumsy.
AllofthischangedhoweverwiththeadventofmorepowerfuldevicessuchastheArgoNavisfromWildcardInnovationsandtheNexusDSCfromAstroDevices(bothAustraliancompaniesinterestingly).Thesedeviceswereperhapsmoreproperlyknownasdigitaltelescopecomputers(DTC’s)ratherthanDSC’s.Boththesedeviceswilltakecometorbitalelementsandcomputepositionsonthefly.Themethodsofgettingtheelementsintothedevicevariesbetweenthetwo.TheNexusrequiresyoutodownloadtheelementsfilefromtheMPCsiteandtheneditittoshowonlythoseobjectsyoumaybeinterestedin(otherwiseyouwillgethundredsofobservablecomets).CopythisontoaMicroSDcardandthenputthatinthedevice(thisworksforasteroidsaswell).TheArgoNaviswilltaketheelementsinaspecialisedformandthiscanbetransferredintothedeviceusingaserialcableeitherusingtheirownprogram,whichisverycrude,oryoucanconnectittootherplanningprogramssuchasSkyToolsandDeepSpacePlannerandloadonlythoseelementsyouwant.
TheoneissuewiththeArgoNavisisthatitonlyallows10setsofcometelementsatatime,butitwouldbeunlikelythattherewouldbemorethan10cometsthatonewouldbechasingvisuallyatanygiventimeanyway.SkyToolsdoesuploaditsowncometelementseverymonth(ormoreoftenifsomethinginterestingsuchasC/2017O1(ASAS-SN1)appearsmid-month).Theowneralsorecalculatesthegandhparameterstomatchwhathascomeinfromhisvisualobservers(althoughsomeofthesehavetobetakenwithapinchofsalt).Theplanningprogramsalsowillprovidecharts,includingeyepieceviews
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forconfirmationandindicationsofthecometsbesttimeforvisibility,soyouknowhowearlyyouhavetogetupinthemorning.
AdmittedlythiscanbedoneaswellwitholdersoftwaresuchasGuideortheBAAComputingSectionwebsitebutbeingabletocustomiseforyoursiteandinstrumentationisarealadvantage.IfindthatevenoldernolongersupportedsoftwaresuchasDeepSky2000hastheadvantageofbeingabletoloadelementsandmakequickchartswhicharesuitabletogetaroughideawhereacometis.DisappointinglyasMPCdoeschangeformatsandURL’ssoftwarelikeGuidewhichusedtobethemainGoTosoftwareforchartingmovingbodies,nolongerdownloadselementsasconsistentlyasitusedto,althoughtheworkaroundistheretodownloadthefilefromtheMPCyourselfandtoloadittakesafewmoresteps.
Withtheelementsloadedthesystemsareusuallyfairlyaccuratewhentryingtolocatecomets(oranythingelse),althoughnotalways.ForreasonsIneverunderstoodwhenobserving41Pearlierthisyeartheco-ordinateswerealwaysoffinbothmyArgoNavisandacolleague’sbyalmost1.5degrees.Forothercometsonthesamenighttheywerespotonsoyoucannotalwaysrelyonthedevice.Itcanalsobeworthtakingpaperchartsjustincasethesystemletsyoudown.AlloftheseDSC’srelyonencodersandtheycanfaileitherbyslippageormudgettingincables(analltoocommonoccurrencewhenyouhavetotrektoafieldtoobserveratherthannicedryobservatory).Itcanbeverydifficultifnotimpossibletoreplaceencodercablesonatelescopeinthedarkandcoldifsomethinglikethishappens.
Whatthistechnologydoesisallowyoutogoaftermuchfaintercometsthanyouwouldperhapshavedoneifyouwouldhavehadtostarhop,asthereisagreaterprobabilityoffindingthem.Youarealsofairlysurethatifyoudonotseeitinornearthefieldthenitisnotcurrentlyvisible.
Theotheradvantagenowistheselectionoftelescopesandtoolsforobservingcomets.ThesoftwareIhavebrieflymentionedbutnowwithwidefieldeyepiecesandtoolsliketheSwanbandfilters(currentlyonlyavailableIbelievefromLumicon)makesiteasiertobothfindtheobjectsandobservesometimessubtledetails.Eyepiecesarealwaysareligioussubjectamongstvisualobserversintermsoffieldandcontrastbutthereisnodoubtthattheexistenceofwidefieldandhyperwide(100degree)fieldqualityeyepieceshavemadeadifferencewhenviewingobjectsusingundriventelescopes.IhaveacometSwanbandfilter(welltwoactually,1.25and2”versions)andthesecanbeusefuloncertaincomets,mostlythosewithastronggascomponent.IwilltryusingthefilteronanycometIobserve,justincase,toseewhatdifferenceitmakestotheviews.ItwasfunforinstancewatchingtheearlyhaloaroundHolmes(17P)witha130mmrefractorwiththeSwanbandasitgrew,althoughtheviewslaterfromadarksiteinDevonwitha50cmtelescopeofthesamecometwithoutafilterwerenotfarshortofphotographic.
Itcanbeusefultohavearangeofsizesoftelescopestousewhenobservingcometsaswell,bothfromtheportabilityaspectand,ifwedogetalargecomet,forthefieldofview.ThesmallertelescopeforinstancecanalsogivepanoramicviewsofcometswithdeepspaceobjectssuchasM31andPanSTARRSafewyearsback.Imustadmit
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thatIhavebeentemptedtoaddaDSLRtothistelescope(atripletAPO)butthehassleofsettingupaportabletelescopeandgettingittrackingandimagingweremorethanIcouldface.Ididplanatonetimetosetupanobservatorywiththistelescopeandacamerainitbutitneverhappened.
TheadvantagesofthesesystemscanbeseenfromarecenttripthatImadetoLaPalmawithAndrewRobertsonwhere,amongstthemanydeepskyobjectsthatwehadprimarilygonetosee,wealsomanagedtoseethreecometsC/2015V2(Johnson),71P/ClarkandC/2015ER61(PANSTARRS).AlthoughthefirstandlastwouldhavebeengoodtofindwithouttheDSC’sbecausetheywerequitebright,71P/ClarkwasamuchmorechallengingobjecttofindbothinitslocationlowinScorpiusanditssize.Itlookedmorelikeasmallfaintglobularclusterthanacomet.Iguessthequestiongoingtobeaskedbymostpeopleiswhyspendsomuchtimetrackingdowncometsifyouarenotgoingtomakescientificobservations.Well,thereisalwaysthefunofwatchingcometsevolveandbeingabletofindthem.
AsunnydayatKellingHeathStarParty-andmyObsession22inchwithAndrewRobertson’s24inchatKellingHeath2016(andbothmuchadmiredbytheEditor)
AtoneKellingStarPartyafewyearsbackAndrewandIprobablymadesomeofthefewvisualobservationsofISONwithlargetelescopesfromtheUK.Admittedlyhebeatmetooitby5minutesbecauseIwasusingtoohighapowereyepiece.Thatwasalsoanimportantlessontolearn.Itisusefultohaveaselectionofeyepiecestohandwhenobservingcometsasitisnotalwaystheoneyouthinkthatwillrecoveritthatactuallyistheeasiesttofinditin.Thisisperhapsastruefordeepskyobjectsaswell.
Thehigherqualityofmirrorsintoday’spremiumDobsoniantelescopesmeansthatingeneralItendtousehigherpowersbydefault(intherange150–200x)thanperhapsusedtobethecasewhenlargeamateurtelescopeswerejustthoughtofasfluxcollectors.Itisalsofuntotrackcometsoveralongperiodastheymovearound.WecanallrememberHale-BoppbutIremembertrackingC/2014E2JacquesforalmostayearuntilitfinallydisappearedintotheMilkyWay.Wealsohadfunwhen225PoutburstandbecamesolargethatitfilledthefieldofthelowestpowereyepiecethatIhad,whichhadoveradegreefield.
Itcanbefuntrackingcometsoveranumberofreturnsaswell.Irememberfirstseeing21PjustbeforetheHalleyapparitionin1985andthoughtthatitlookedlikeapropercomet,unlikeHalley,whichwasalwaysadisappointmentfromtheUK.Thatapparition,withasmalltail,isonethatIhavefollowedatanumberofapparitionssince.IremembertryingtotrackacometfromtheoriginalsiteoftheEquinoxstarpartyatThetfordinNorfolkandgettingannoyedbecausetherewasanauroraintheway.
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ItistruethatitisbecomingmorechallengingtofindandobservecometsvisuallyfromtheUKwhatwiththeincreasinglightpollutionandtheinclementweatherandgiventheirpropensitytoappearinthemorningskies.ThisisparticularlydifficultasdespiteallthesedarkskyreservesbeingsetupintheUKingeneraltheyonlymeasurethenightskybrightnessatthezenithandinmostcasestheseplacesstillsufferfromstronglightpollutionlowdownwhereyouwouldlookforcomets,perhapstimefortheIDAtorelookathowtheymeasureskybrightnessherebeforethewholethingbecomesamockery.Icanseetheadvantageofhavinganautomatedimagingsetupsoyoujustplugitinandaskittoobservewhilstyousleeporsitinanicewarmroom.
Therehavebeenoccasionswhenwehavetriedtheimpossiblewhenobservingcomets.IremembertryingtoseeSL9justbeforeimpactwithStevenO’Mearaandothersusinga36”telescopefromtheTexasStarparty,afrighteningexperiencebeingupan18footladderevenonhardgroundtryingtomovethetelescope.Wefailedanyway.Whenwehavehadbrightishcometsthefactthattheycanbeseenwithbinocularscanalsobeanadvantage.
TheAuthorandhisfinecaravan
OvertheyearsIhavehadtotravelalotwithworkandbeingabletotakebinocularshasmeantIhavebeenabletokeeptrackofcometsevenwhennotathome.Thisyear,sofar,thecomettallystandsatthefollowing5comets45P,41P71P,C/2015U2andC/2015ER61.AnattempttofindC/2017E4Lovejoyearlierintheyearendedwithatelescopebrokenontheground,oneofthechallengesoftryingtogooutatthreeinthemorninganddrivetoasiteandsetup.Itissometimesachallengetoconfirmwhathasbeenseenanditisusefulaftertheeventtogoandcheckimagestakennearthetimeofobservation.
Oftenwecanseesubtleeffectsthatareoverexposedonimages.Idonotlookatimagesbeforegoingoutasitcaninfluencewhatyouthinkyoucansee,somethingknownalltoowellbydeepskyobservers.Itispossibletofoolyourselfintoseeingobjectsthatarenottherebecauseofseeingconditionsorthinkingtheyarethere.Unfortunatelyrecently,cometshavenotbeenthatusefulinoutreacheventsasmostpeopleexpectatailandsomethingdramaticandaroundfuzzyblobdoesnotreallygrabattention.Thiscanalsohappenwithotherlessexperiencedastronomersaswell.Seeingsubtlefeaturesintailscanbehardandtakespractice,muchasanyaspectofvisualobserving,andmanypeopledonothavethetimeorinclinationtodothisanymore.ThiswastruewithbothHale-BoppandHyakutakewheretherewasalotofdetailthatcouldbeseeninthecomawithjetsonthewayin,particularlywithlargetelescopes,eveninthosedaysIwasusinga50cmtelescope.
UnfortunatelyoneofthethingsIhavefailedtodoovertheyearsiskeepalogof
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allthecometsIhaveseen,althoughIexpectitiswellover50andprobablynearer100.MyfirstexperienceofastronomywasinfacttryingtoseeCometIkeya-Sekiin1965fromTorontoandalthoughIwasveryyoungitwasthisthatgotmeintoastronomy.Unfortunatelywefailedtoseeitonthatoccasionanditwouldbeanother10yearsbeforeIfoundmyfirstone.
OwenBrazell
6 ObservingHalleyfromTenerife-RichardJones
Figure1
TheapparitionofthenotoriouscometC/1973E1KohoutekfirstinspiredDenisBuczynskiandmein1974.This,asthemediahadusbelieve,wouldbethecometofthecentury;abletobeseenindaylightwithatail100degreeslong.Whatalet-down!Ithardlymadenakedeyevisibility.
Iwassofrustratedatnotbeingabletofindit,nightafternight,thatInearlygaveup.ThenoneclearJanuarynight,inicyconditions,Itookafive-minuteexposureofwherethecometwassupposedtobe,(seeFig1)andsureenoughIhadcapturedit,inthesodiumlightpollutedskiesover
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Chester.Thiswasmyfirst"bagged"comet.Thatonephotographignitedmycontinuinginterestinphotographingthesky.
Inthesummerof1985,myexcitementwasbuildingforthereturnofwhatIhavealwaysconsideredtobeaveryBritishcomet,Halley's.Imadeupmymindtobagthatonetoo.IdecidedtogotoTenerife,whichIhopedwouldproveanaccessibleplacewheregoodtransparencycouldbeguaranteed.
Myplantodoadummyrunthere,inNovember1985,tocheckoutallmyequipmentandtofindtheoptimumsitetosetitup,gotofftoashakystart.IhadbookedmyflightfromManchester.Tocoveralleventualities,IhadpackedmyOrangeCelestronC-8OTA,atrackingmount,withelectroniccontroller,guidingeyepieceandtripod,twocameras,mediumformatand35mmSLR,severallenses,anddifferenttypesofnegativeandpositivefilm.Iwaswellinexcessofthe20Kbaggageallowanceevenbeforefactoringinachangeofclothesandatoothbrush!ItwaswithdelightandreliefthatIwelcomedthewordsfromtheircustomerserviceteam,"Sir,weatBritanniaAirwaysdonothavealimitonbaggage".Ichosetoignoretheirprovisothatintheeventoftheaircraftbeingoverweightonthedaymygearwouldcomeofffirst.
OnFriday8thNovemberIwasofftophotographHalley'scometfromoneofthebestviewingplacesintheworld.IarrivedinTenerife(South)andhiredacheapcarforaweek,whichwouldalsodoubleasmy12-voltpowersupplytodrivetheCelestronC-8electronics.MyaccommodationwasatsealevelinPlayade
lasAmericasbutasitwasstillearlyinthemorning,ItookaquickdriveuptotheMountTeideNationalParktocheckouttherouteandtheroads.Inthosepre-EUinvestmentdaysof1985/6themountainroadswereverynarrowanddangerouswithsteepdropsoneitherside.Irealisedgoingupthereatnightwasgoingtobeachallenge.
Atbreakfastonmyfirstmorning,InoticedheavycloudhadmovedintocoverthetopofMountTeide.Itookadriveupthere.Itwaslikedrivinginapeasouper.Theonlyclearspotwasrightatthepeak,officiallyofflimitstothepublic,withnoflatgroundandat12,000ft.,andverylittleoxygen.Seefigure2below.
Figure2
Disappointmentloomed,especiallyasdayafterdaytherewerenosignsofabreakintheweather.Ibegantothinkthisisallgoingtoendintears,goinghomewithoutasingleskyphoto.Onthenightbeforeflyinghome,Iwentonelasttimeuptothemountain.StormornostormIwasn'tgoinghomeemptyhanded.Isetupmyequipmentinhighwindsandclungon.Afteragruellinghour,Igotabreakinthecloudsandmanagedtoguideafive-minuteexposure,ofHalleyinbound,Seebelowfig3.0thegreen,inmiddleofpicture.
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Figure3
Ididn'tfeeltoobad;atleastIhadoneimagetotakehome!Asweknow,clearnightsinUKarefewandfarbetween.MynextopportunitycameinJanuary1986.Thisparticularafternoon,ithadsnowedandafterthesnow,theskiessuddenlycleared.Iquicklyloadedeverythingintothecar,includingasnowshovel,droveoutandsetuponafarmer'sdrivewaysomewheresouthofChester.Iwasjustabouttotakemyfirstexposure,whenaboomingvoicecameoutofthedarkness,"Whatthe'Bl..dy'helldoyouthinkyouaredoing!".Therestoodthefarmerwithhisshotgunoverhisarm.IpolitelyexplainedthatIwasanastronomertryingtophotographHalley'scomet.Hisbelligerentmoodchangedinaninstant.Heaskedifhecouldbringhischildrentoseethecometthroughthetelescope.Ireplied,“Ofcourseyoucan,butgiveme15minstogetaphoto"(HalleyinJanuarywassettingcloseaftersunset).Hecamebackasarranged,withhisthreechildrenandtheyallsawthecometthroughtheCelestronC-8eyepiece.Weallfeltgoodabouttheencounter.
MynextplannedcometphotographingexpeditionwastoMountTeideagain.ThiswasgoingtobethemainshowandthedaystickedbyasIkeptmyfingerscrossedforbetterweatherinApril.Thistimetheweatherwasgood,reallygood,somy
expectationswerehigh.However,insteadofcloudshamperingme,therewereotherobstaclestoovercome.Itwasnotpossibletogetaccommodationinthenationalparkitself(exceptattheexpensiveParadorHotel)soIhadtomakenightlytripsupthemountain.Iwasunpreparedforthesheerfatigueandexhaustionresultingfromthedrivingtask,stayingupmostofeverynightandgettingfartoolittledaytimesleep.Ononeoccasion,Ifellasleepatthewheelbut,luckily,cametoojustbeforethecarwasabouttocareerovertheedge.Itseriouslyshookme,soIcontinuedthejourneywiththeheateroffandthewindowdown,singingloudlytokeepmyselfawake.
Findingtheoptimumsiteprovedchallenging.MyfirstimagesweretakeninthecarparkacrosstheroadfromtheParadorHotel.Thisprovednottobeagoodlocationasitwaspopularwithtoomanyyoungcoupleswantingtoparkup,andtherewereproblemswithheadlights.Inexttriedtheroadleadinguptothecablecarride.ThistooprovedproblematicastheroadwassosteeplyslopingthatitwasveryawkwardtopolaralignmyCelestronmount-achorethatwouldhavetodoneeverynight.
Figure4
MyfinalplaceofsetupwasattheMountTeideObservatory(InstitutodeAstrofisicaIAC)towardstheNorthendoftheisland.
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Seefig4.0above.Inthosedays,therewasnosecurityonthemaingatesoIdrovestraightuptothe2.5mIRTelescopeandaskedRodriguez,whoappearedtobeinchargeofit,ifIcouldsetupnexttohisdomeformyimaging.HeaskedmevariousquestionsonCosmologyandseeminglysatisfiedwithmyanswers,gavemepermission.Thisprovedtobetheperfectlocation,veryhighandverydarkandwheremostofmyimagesweretaken.Fig5belowshowssunrisefromabovethecloudsthere.
Figure5
Inthosepre-digitaldays,Iusedthefollowingequipmentformyimaging:ACelestronC-8,usedpurelyasaguidingplatformtophysicallyholdthecameras;35mmMinoltaSRT-101andamediumformatPentagonSix.(Ilosta12-imagerollofexposedfilm,takingthefilmoutofthatcamera).Iused50mmf2.8,180mmf2.8,300mmf4,500mmf5.6lensesandfilms:Tri-XNeg400ASA,Fujichrome100ASA,Fujichrome400ASAand3M1000ASApositive.
AlltheimagescanbeviewedintheBAAArchiveunder1P_1985&1P_1986
Twoimagesofspecialnoteareincludedhere:theoriginalimageanditsphotoamplifiedversion.Seefigures6and7.
Figure6
Figure7
DavidMalin,oftheAATfameinAustralia,madeavaluablecontributiontoAstronomicalSciencebyamplifyingweaknegativestobringoutextradetailinthethinareasofthenegative.Iusedaslightlydifferentmethod,suppliedbyaphotoengineeratKodakLondonandoutlinedinfig7.0above.IwasthrilledwhenIreceivedthephotoamplifiednegative,asitshowedIhadcaughtataildisconnectioneventthatIhadnotnoticedontheoriginal.
Accordingtothescience,thiseventoccurswhenthetailofacometpassesthrougha
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solarsysteminterplanetarymagneticfieldlinereversal.Theplasmatail(blue)containselectronsandions,whicharestronglyaffectedbymagneticfields(asinthebeamofanoscilloscope,deflectedbyelectro-magnets).Thesuddenreversalcausesthetailtodisconnect.Itissometimespopularlycalledthe"brokenlegeffect".Itdoesn'taffectthedusttailasthedustisnotionised.
Theexpeditionendedwithonepotentiallyalarmingincidentbeforeboardingtheflighthome.WhengoingthroughsecurityatTenerifeairport,everythinghadtobeX-Rayed.Ibegantoprotestwhereuponthreeguardswithgunsconvergedonme.IexplainedaboutphotographingHalley.Luckilyforme,theSpanishwerewellinformedabouttheComet,andmyfilmsandequipmentstayedintactandwereallowedthrough.Wasitworthallthe
effortandexpense?Youbetitwas,Iwon'tbearoundin2062whenHalleynextgracesourskies,sosecuringthose20imagesfromTenerifewas,forme,anunrepeatableandunforgettableexperience."Aonceinalifetime."
RichardT.JonesI.Eng
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7 FromtheArchives
TheEclipseCometof1948–NickJames–SectionDirector
ThisisthefamousphotographofcometC/1948V1takenfromanRAFaircraftoverKenyaduringthetotaleclipseof1948Nov1
TheCometSectionarchivecontainsalotofinterestingmaterialandourobjectiveistogetmuchofitscanned,indexedandonlineoverthenextfewyears.IhavebeengraduallysiftingthroughthematerialandIcameacrossthisinterestingcorrespondenceconcerningtheeclipsecometof1948.
Thecometwasdiscoveredduringthetotaleclipseof1948November1whichwasvisibleonatrackstartinginthethenBelgianCongoandwhichcrossedNairobi,KenyabeforeheadingoutovertheIndianOceanandendingupsouthofAustralia.Thecometwasseenbymanypeoplebutitwasalsophotographedduringtotality
27
fromanRAFaircraftflyingat13,000ft.overKenya.
Thecomet’sdesignationatthetimewas1948landthemoderndesignationisC/1948V1.
SomedetailsoftheRAFphotographweredescribedbyRobertd’EscourtAtkinsonataBAAmeetingheldonNovember24atBurlingtonHouse(JBAA59,2).
Unfortunatelyitonlyseemstohavesurvivedasverypoorreproductions(seetheexamplehere).IwasthereforeratherexcitedwhenIcameacrossafolderofcorrespondencemarked1948.SadlytherewasnoprintbuttherewassomeinterestingcorrespondencebetweenMertonandseveralothersincludingAtkinsoncoveringtheperiodaftertheeclipsewhenthecometwasabrightmorningobjectmovingsouththroughHydra.Someexamplesarereproducedhere.
28
I’mstillhopingthatI’llcomeacrossahighqualityprintoftheRAFimagesomewhereburiedinthearchivebutnoluckyet.
NickJames-SectionDirector
CometObserversofthePast–HistoriesContributionsandAchievementsDirector’sNote-Thissectionintroduceshistoricalperspectivesoncometdiscoveries,theirroleingeneralsocietyandinpolitics.Ihopeyouenjoyitandalsofeelfreetocontribute.
8 Comet38PStephen-Oterma,TheDiscoverers,anda“New”searchanddiscoverytelescope(1930’s)–byDenisBuczynski
ThisperiodiccometreturnstoperihelioninNovember2018.Itwasfirstdiscoveredin1867,thensubsequentlylost.Uponre-discovery77yearslateritwasseentohavemanyinterestingaspectsforastronomers,observatoriesandinstruments.
AlthoughthecometwasfirstnamedafterE.J.StephenofMarseilleObservatoryinFrance,itwasactuallydiscoveredonJan221867byJ.E.Coggia,an18yearoldassistantatthesameobservatory.AfewdayslateronJan24E.J.Stephenwasabletomakeconfirmatoryobservations,andcruciallyprovidedaccuratepositionsandmotion.Whentheseresultswereannouncedtotheastronomicalworld,Stephen,theObservatoryDirector,wascreditedwiththediscoveryandtherebyhisnamewas
attachedtothecomet.ItwasobserveduntilMarch1867andastronomersinAmericawereabletocomputeanorbitwithaperiodofapproximately40years.ThismeantthatthecometwasinaHalley-typeorbitandpredictionsofitsreturnwerefortheyearsbetween1902and1912.However,thecometwasnotrecoveredduringthispredictedreturnperiodanditwasconsideredtobelost.
In1942,duringWorldWar2,theFinnishastronomerLiisiOtermadiscoveredacometusinganewly-inventedtypeofwidefieldreflectingtelescope.ThisturnedouttobethereturnofComet38P,whichisnownamedStephen-Oterma.Thecareerandlife(1915-2001)ofthisastronomerisafascinatingoneandworthyofdescription.
29
HercareerwascloselyassociatedwithanothermorefamousFinnishastronomer,YrjöVäisälä.
Otermainheryoungeryears
In1924Väisäläwasinvolvedinopticaldesign.HehadindependentlyinventedthesametelescopeconfigurationasBernhardSchmidt,butrecognisedthatthecurvedfocalsurfacewasalimitationofthesystem,andabandonedpublicationofhisinvention.HoweverwhenSchmidtpublishedthedetailofhissystemin1935,Väisäläreturnedtohisowndesignandimproveditbyplacingafieldflattenerclosetothefocalsurface.ThisdesignbecameknownasaVäisäläcamera.Untilthesefastwide-fieldcameraswereinvented,asteroidandcometphotographicdiscoverieshadbeenmadeusingtripletlenssystemsoperatingintherangeoff/4-f/6.Thediscoveriesintheyearsfrom1900to1930weredominatedbyastronomersemployinglenssystemssuchasthosebyZeisswhichwereusedbyMaxWolfatHeidelberg,andtheHarvardObservatories’Metcalfcameras.TheCooke/Taylorlenseswerethelastimprovementofthelensdesign.The
attractionofthenewreflectingcameraswastheshortfocus,largeapertureandsubsequentfastspeed,aroundf/2.Thismeantthatlargedeepfieldscouldberecordedinrelativelyshortexposures.Thesetypesofinstrumentswereidealforsurveywork.
LiisiOtermastudiedmathematicsandastronomyattheUniversityofTurkuinFinlandunderProfessorVäisälä,andwhenheestablishedanobservatoryintheearly1930’sfortheUniversityatIso-Heikkiläheappointedhisverybrightandcapablestudentashisobservingassistant.Duringtheearlyyearsoftheobservatory,VäisäläandOtermamadetheopticsfortheobservatorytelescope.
VäisäläandOtermaproducingopticsatTurku
Thiscomprisedaprimarymirrorwithafocallengthof1031mm.Thesphericalprimarymirrordiameterwas600mm,anditwasonaGerman-typeequatorialmount.Ituseda120mmdiameterdoublyconvexfield-flatteninglens3mminfrontofthefocalplane,whichgaveita6.7degreediameterfieldofviewon120x120mmfilmplates.Thisprovidedascaleof200arc-secondspermm.OtermawasparticularlyexpertinopticalworkandtogethersheandVäisälämadelargeopticsfor
30
observatoriesaroundtheworld.TheyproducedthemirrorfortheUppsalaSchmidttelescopewhichwasoriginallylocatedatMountStromloinAustraliaandwasusedtotakethefirstimagesofSputnikin1957.ItwasthenrelocatedandinstalledatCoonabarabranalsoinAustraliaandwasusedbyRobMcNaughttomakehiscometdiscoveries.
OtermaandVäisälä(topright)attheTurkuObservatory
UsingthenewVäisälä500/600/1031camerafrom1935theTurkuObservatorysearchprogrammewasverysuccessfulanddiscoveredmorethan800asteroidsand7comets.OtermawasdeeplyinvolvedinthissearchprogrammeanddespitetheverycoldwinterconditionsattheFinnishobservatoryremaineddiligentinherwork.Shediscoveredaround200asteroidsand3cometsduringthisperiod.ShealsofoundtimetocompleteherMaster’sdegreein1938.Shewasproficientatthecalculationoforbitsandcomputedorbitsforherowndiscoveries,includingtheperiodiccometsassociatedwithhername.
In1955Otermapublishedherdissertation,notonminorplanetsbutontelescopeoptics.Itdescribedmethodsforoptimizing
theuseoflargetelescopes.Thedissertationreceivedthehighestmarks,andOtermabecameDoctrixPrimaatthedegreeceremonyatTurkuUniversity,heldinthesameyear.ShewasthefirstfemalePh.D.attheirFacultyofSciencesandalsothefirstwomaninFinlandtoachieveaPh.D.degreeinastronomy.In1956,theFinnishallianceofbusinessandprofessionalwomenchoseherastheir"WomanoftheYear”.In1959shebecameaDoctorofAstronomyandin1962ActingProfessorofAstronomyatTurkuUniversity,andthenProfessorin1965.AfterYrjöVäisälä'sdeathin1971,shealsoservedasDirectoroftheAstronomical-OpticalResearchInstituteatTurkuUniversityuntil1975.Sheretiredin1978.
Shehadthereputationofbeingareticentandunpretentiousperson.Shefeaturedinanarticle"CometOterma"inthemagazineKansanKuvalehtiin1950,whichdescribedherscientificreputation.ItrelatesthatanItalianastronomer,whometOtermain1948ataninternationalastronomicalcongressinSwitzerland,toldherthathehadthoughtthatshewouldbeanoldmanwithalongbeard.
ProfessorAndersReizfromtheobservatoryofCopenhagenwhoknewaboutOterma'sinterestinlanguagessaidthatshe"keepssilentinelevenlanguages".Oterma'sproficiencyinlanguagesincludedGerman,English,Spanish,Italian,Hungarian,EsperantoandFrench.ShechosetowriteherdissertationinFrench.Asapersoninterestedinlanguages,itwasnaturalforhertoconcludeherinaugurationlecturewiththoughtsaboutwhethertherewereothersentientbeingsintheuniversewithwhomhumanscouldexchangemessages."Thenearestplanet
31
withbeingswhomightbeinterestedincommunicatingwithuswouldbelocatedwithinadistanceof300lightyears.Ifourneighbourcivilisationshavedeveloped,say,afewhundredyearsfurtherthanus,theyhaveprobablysentusmessages.Weonlyneedtolisten."
Oterma’scometswerediscoveredduringtheSecondWorldWarandcommunicationsbetweenobservatorieswereseverelydisruptedanddelayed.Itwasthereforeimportantthattheorbitsforthesecometswerecomputedin-housesothatthepossibilityoftheirbeinglostwasreduced.IndeedherfirstcometC/1942C2wasonlyobservedatTurku.
Hertwoperiodiccometswereimportantdiscoveries.Comet38Pturnedouttobethereturnofthe18671CometStephen.ThedisruptedcommunicationsmeantthatthiscometwasindependentlydiscoveredbytwoseparateobservatoriesinGeorgiaandUzbekistan.ThelinkwithCometStephen18671wasmadebyFredWhipplein1942andheestablishedtheperiodasbeingaround38years.HerComet39PturnedouttobeunusualinthatitwasfoundtohavehaditsorbitaffectedbycloseencounterswithJupiter.Ina1962paperbyBrianMarsdenentitled“ViolentChangesintheOrbitofCometOterma”heoutlinedtheseeffects.SincethenitsorbithasbeendescribedasaquasiHildatypecometandnowasaChirontypecomet.Atitsnextperihelionin2023itislikelytobeasfaintasmagnitude22.
The50cmVäisäläcamera/telescopeatTurkuObservatory
The2018apparitionofComet38PisthusdescribedbyJonShanklin,“ItshouldcomewithinvisualrangeinSeptemberasitbrightensrapidlyonitswaytotheNovemberperihelion.ItwillbeatitsbrightestinNovember,whenitisinthelateeveningskyandremainswellplacedinto2019.”
Soasweturnourtelescopestowardsthisfamousreturningcomet,wecanrecalltheobserversofthepastwhomadeimportantobservationsandremembertheveryimpressiveLiisiOterma,herextraordinarycareer,andherimmensecontributiontoCometscience.
InthisarticleIhavereliedheavilyoninternetsourcesandgivelinkstorelevantarticlesbelow.MuchdetailwasextractedfromIvaIsaksson’sbiographyofLiisiOterma.
http://cometography.com/pcomets/039p.html
http://cometography.com/pcomets/038p.html
32
http://adsabs.harvard.edu/full/1962ASPL....8..375M
https://en.wikipedia.org/wiki/38P/Stephan%E2%80%93Oterma
http://www.helsinki.fi/akka-info/tiedenaiset/english/oterma.html
www.zmailer.org/m/ursa/oterma-thesis.pdf
https://en.wikipedia.org/wiki/Yrj%C3%B6_V%C3%A4is%C3%A4l%C3%A4
DenisBuczynski–CometSecretary
9 Memories of Comet Honda-Mrkos-Pajdusakova (1974-f) withthoughts of its splendid 2016-2017 return as Comet 45P – P. ClaySherrod
Comet45p2016Dec22MichaelJaeger
AsCometHonda-Mrkos-Pajdusakova(45P)streakedacrossournighttimeskieslastwinter,displayingabeautifulgreencomaandlonglineartailseveraldegreestothenortheast,IwasinspiredtogointotheArkansasSkyObservatories'Archivesof
boundresearchdocumentsandfindmyrecordsofobservingthiscometin1974and1975.BarelyvisiblevisuallyinourskiespriortotheremarkableCometWest(1975n)in1975,comet45P.CometHonda-Mrkos-Pajdusakovawasdiscovered
33
longbeforeIfirstobserveditin1974,andhadbeenmissedorveryunfavourablyplacedforobservationsinceitsoriginal
discoveryin1948bythreecomethunters,M.Honda,A.Mrkos,andL.Pajdusakova,eachspottingthecometindependently.
Thusthisinterloperwasnamedafterallthree,whosimultaneouslyfoundthiscometatmagnitude9asaveryfaint"smudge"oflight,quitediffuseandwithoutanucleusortail.Thecometinthatyear
rapidlyfadedtomagnitude13andwasnotseenagainuntil1954whenitreachedmagnitude8.4onlyforaveryshortperiodoftime.
Withitsorbitalperiodofonly5.3years,wewouldthinkthatthiscometwouldbeeasilyvisibleateachpass,butthisiscertainlynotthecase;itwasnotvisiblein1959becauseofthegeometryoftheEarth-Sun-Cometorientation,butitwasobservedverysparinglyinsubsequentpassages.Itwasnotuntilthewinterof1974-75thatthecometwouldbecomefavourableforobservationsineveningskies.Bythattimethereweremanymoreobservers,bothamateurandprofessional,whoweretakingakeeninterestinthenatureofcomets.
In1974-75,wehadjustseenthepassageof"TheCometoftheCentury,"CometKohoutek1973-f,regrettablydeemedtobethebrightestcometperhapseverseeninmoderntimes.Theworldawaitedthiscometwitheageranticipationandthousandsofsmalltelescopesweresoldtoanunsuspectingpublichopingtocatchthismedia-frenziedcelestialvisitor.WhenthecometwasfirstdiscoveredbyCzechastronomerLubosKohoutek,itwassofarawayinoursolarsystem,yetsointrinsicallybright,thatDr.BrianMarsdenoftheHarvard-SmithsonianAstrophysicalObservatoryproperlysurmisedthatbythetimethecometwouldcomeintotheEarth'vicinity,itwouldbeincrediblybrightandthusthecometmaniagrew.
ButsoonwerealizedthatCometKohoutekwasgoingtobethefizzleofthecenturyandmanyofboththegeneralpublicandtheastronomicalcommunitywasdiscouragedfromtherealmofcometexploration.
Buttheearly1970'sbroughtanincredibleinfluxofbrightandexcitingcomets,most
ofthemignored,under-observedormissedentirelybytheapathyoftheKohoutek-burnedhumanrace.Imustadmit,thatcomet1974-fwasnotamongstthoseexcitingcomets.ButatthetimeIwashookedoncometobservingandDr.MarsdenhadbecomemymentortocontinuetomonitorallthatIcould.AphonecalloneeveningattheobservatoryfromMarsdenwasallthatIneededtoimmediatelyturnourmodesttelescopesinsearchofCometHonda-Mrkos-Pajdusakova.Ourfirstattemptstolocatethecomet,alldonevisuallyatthattime,wereunsuccessful;thenow-veterancometobserverJohnBortlewasthefirsttospotitinhis12-inchNewtonianonNovember15atafaintmagnitudelessthan12.5;hisnexteffortonDecember4sawthecomethadbrightenedtoastill-dimmagnitude10.4.
ByDecember10,1974,usingtheCometSearchingsix-inchf/5widefieldrefractor,thecometwasspottedatArkansasSkyObservatoriesbyvolunteersJimHenryandJohnEvansandmyself.Itappearedasnothingmoreinthelowpowerfieldthanasmudgeofdiffuseglow,butwehadpickedupthecometnonethelessandreporteditaswedidallcometstotheSAO/InternationalAstronomicalUnion'sCentralBureauofAstronomicalTelegrams(CBAT)asaveryfaintextendeddiffuseobjectonlythreearc-minutesacrossandmagnitude10.8visually.
1974CBATs
34
TheIAU/CBATTelegramthatwasdistributed(mailed)Dec.13,1974
AlthoughphotographywasavailabletousattheEdgehillfacility(tolaterbedesignatedHarvardMPCObsCodeH43),thepracticeatthetimewastorecordphysicalparametersandmorphologyvisually.ThefollowingismyreporttoDr.Marsden,Mr.DennisMilanofbothSkyandTelescopemagazineandtheCometRecorderfortheAssociationofLunarandPlanetaryObservers,andtoDanielGreen(nowthedirectoroftheCBAT)whoeditedTheCometoutofNorthCarolina.
"IsearchedonNovember28,December2,3,4,5,8,9andtonight(Dec.9)photographedtheexactareawherethecometshouldbereachingstellarmagnitude13withthe6-inchatprimefocus....starsof12thand13thmagnitudewerequiteobviouson10to15minuteexposures.
"Tonightthecometwasfinallyspottedwithsomedifficulty....transparencywasexcellent(6thmag.starsvisibletothe
nakedeye)andseeinggood.At23.5xinthe6"thecometwasatfirstnotvisible,howeverwith60xitwasquiteobvioususingavertedvision.Notailwasvisible,nordiditshowanynuclearcondensation[nucleus].Itappearedasaborderlessdiffuseglowapproximately3arcminutesdiameter....thecometbeingonlyabout12degreesabovethetreesinthedistance....enclosedisaquickdrawing....."
45P1974Notaworkofart,butaquicksketchdone43yearsagoatthetelescope
Andnow,43yearslatermuchhaschangedintheworldofastronomyandotherwise.Comet1974-fisonceagaininmyeveningskies,butnowasComet45PHonda-Mrkos-Pajdusakova.After70yearsofalwaysbeingnotedasadiffuseglowwithnocentralcondensation,theremarkableComet45PasshowninphotographerMichaelJager'soutstandingphotoattophasbeenanobjectwellworthmonitoringandwatchingfortheseoldeyesafterfivedecades.
Today,withmodernCCDcameras,digitalcomputerisationprocessingofimages,andprecisiontelescopesonlydreamedofin1974,weareabletocapturewhatwereoncecalledfaintdiffuseobjectswiththeclarityandsplendourthattheytrulypossess.Muchhaschanged,notonlyintheequipmentthatweuse,butalsoinourunderstandingofthesecomets,visitorsfromthedepthsofoursolarsystemof
35
whichwearestillhangingontouncertaintiesandsomemysteriesoftheirnatureandorigins.
PClaySherrod
10 Editor’sWhimsy–TheCometStone
Whilstscratchingmyheadtowritesomethingentertainingandsomehowconnectedtocomets,Iwasdelvingintomyphotoarchives,tryingvainlytocreateorderoutofchaos,whenIpulledoutmyimageoftheCometStone…
Archeoastronomy3isagrowingscience.Oneofthefirsttowriteaboutmegalithiccircles,alignmentsandstandingstoneswasAlexanderThom(1894-1985).
AlexanderThom
Hewasanengineer(ForthBridgeandflyingboats,BrasenoseCollegeOxford)andisknownforhistheoryofthemegalithicyard(.83metres),whichhesuggestedwasastandardprehistoricmeasurement.Consideredalittleoffpisteoccasionally,hespenthisweekendsdragginghisfamilyaroundancientsitesandsuggestedthatseveralcircles/eggs/ovoidswerebuiltasastronomicalcomplexestopredicteclipsesvianineteenyearcycles.Thomwentontoidentifynumeroussolarandstellaralignmentsatstonecircles.HeproposedthattheprehistoricpeoplesofBritainmusthaveusedasolarmethodofkeepingcalendar.Hesuggestedayearbasedonsixteenmonths;fourwithtwentytwodays,elevenwithtwentythreedaysandonewithtwentyfour."Wedonotknowhowsophisticatedprehistoricman'scalendarwas,buttheinterestingthingisthatheobtaineddeclinationsveryclosetothosewehaveobtainedasideal"4
Morerecentresearchisindicatinghowinternationalsitesmaybelinked.5Hamperedwithnowrittenrecordsalotof
36
whatispostulatedisspeculation.Stoneslastalongtime.ButitwouldalsoappearthatinthemildersouthernregionsoftheBritishIsles,therewerealsomanycirclesbutmadeofwood.Andplottingallsiteshas,withthehelpofaerialphotographyledtoabetterunderstandingofhowtheyarepositionedandjusthowcommontheywere.
AfterhavingfeastedonMrThom’swritingsIembarked,lastspring,onalong-plannedtriptotheOrkneyIslands.IhavealwaysenjoyedvisitingtheseenigmaticsitessinceIwasagirl.IwasborninNorthernIrelandandthewholeofIrelandisrichintheseremains,manynowknowntobeolderthanStonehenge.
StonesofStenness,Orkney
IplannedadaytotourtheStonesofStenness,SkaraBraeandtheRingofBrodgar.TheRingofBrodgarisbelievedtohavebeenbuiltaround2500bc,butthecentreoftheRinghasneverbeenfullyexcavated.StennessandBrodgararepositionedalonganarrowisthmus.Botharepartofa970sq.kilometreareacontainingover80megalithictombs,250roundbarrows,moundedearthenburialsites,and100shortcists,stone-linedgraves.Withinanareaoffourkilometresinlengthandonekilometrewidtharethe
threehenges,Bookan,BrodgarandStenness.Therearealsomany‘outliers’,standingstones,suchastheOdinandthesubjectofthisarticle,theCometStone,ona,possibly,ceremonialroutebetweenStennessandBrodgar,andmultiplepassagetombs,includingMaesHowe.
TheRIngofBrodgar,Orkney
OnapproachingtheRingofBrodgarIwasdivertedbyasmallsignposttotheCometstoneitself.Itstandsabout140metrestotheeastoftheRing,alonesomemonolith.Itisabout1.75metrestall,andhasnomarkingsonit.
ImagecourtesyofOrkneyjar.com
37
Therearerootedremainsoftwootherstonesbesideit,buttheyarenoteasilyvisibleintheovergrowngroundonwhichitstands.Perhapstheyformedatablelikedolmengrave.
WhatisknownisthatthenameCometStoneisarelativelylateraddition,probablyaroundthe19thcentury,andthatfancifulsuggestionsthatitactuallyrepresentedaknowncometinorbitaroundtheRingare,alas,justthat–fanciful.InthepasttheRinghadbeencalledtheTempleoftheSun.TheStonesofStennesswereconsideredtobetheTempleoftheMoon,duetotheircrescentlayout-althoughthatmayhavebeenduetotheanticsofafarmerwhoblewafewofthemupinordertoploughastraightfurrowinhisland.Fortunatelysomeenlightenedneighboursstoppedhimbeforehedestroyedthemall.
Onewellknownlocaloftheperiod,GeorgeMarwick,recordedthathehadheardothersrefertoitastheUlieStone,meaningoilstone.Itwasatraditionthentosalutethestone,aswasoftenwasdoneinruralareas,andthesestoneswere‘anointed’withoil,beeswaxorhoney.Thiswastoplacatetheelvesthatinhabitedtheareaaroundthem.TheCometstonealsohadastoryattachedtoitthatitwastheremainsofapetrifiedfiddler.6
InNorthernIrelandstandingstoneswereoftentobefoundpaintedred,whiteandblueorgreen,whiteandgolddependingonthepoliticsofthelocalleprechauns….
IfyougetthechanceIcannotrecommendenoughatriptothisbeautifulareaoftheBritishIsles.ButdoreaduponyourAlexanderThomfirst,justtoaddtotheinterest.
TheharbouratKirkwall,Orkney
1ThetermarchaeoastronomywasfirstusedbyElizabethChesleyBaity(atthesuggestionofEuanMacKie)in1973,[15]butasatopicofstudyitmaybemucholder,dependingonhowarchaeoastronomyisdefined.CliveRuggles[16]saysthatHeinrichNissen,workinginthemid-nineteenthcenturywasarguablythefirstarchaeoastronomer.RolfSinclair[17]saysthatNormanLockyer,workinginthelate19thandearly20thcenturies,couldbecalledthe'fatherofarchaeoastronomy.'EuanMacKie[18]wouldplacetheoriginevenlater,stating:"...thegenesisandmodernfloweringofarchaeoastronomymust
surelylieintheworkofAlexanderThominBritainbetweenthe1930sandthe1970s.Wikipedia1 ·AlexanderThom(1August1967).MegalithicSitesinBritain.OxfordUnivPronDemand.pp.107–.ISBN978-0-19-813148-9.Retrieved4June20111http://www.independent.co.uk/news/science/archaeology/stone-circles-secrets-research-callanish-stenness-scotland-orkney-gail-higginbottom-a7201096.html
38
1http://orkneyjar.com/history/monoliths/cometstone.htm
JaniceMcClean-Editor,Comet’sTaleandNewsletter
11 CometSectionContacts
Director NickJames,11TavistockRoad,CHELMSFORD,Essex. CM16JLEngland.Phone:(+44)(0)1245354366E-mail:[email protected]
VisualObservationsandAnalysis: JonathanShanklin,11CityRoad,CAMBRIDGE.CB11DPEngland.
Phone: (+44)(0)1223571250(H)or(+44)(0)1223221482(W)Fax: (+44)(0)1223221279(W)E-Mail: [email protected]@bas.ac.ukwebsite:http://www.ast.cam.ac.uk/~jds/
Secretary: DenisBuczynski,Templecroft,TarbatnessRoad,Portmahomack,NearTain,Ross-
ShireIV201RDScotlandPhone:(+44)(0)1862871187E-mail:[email protected]
TALiaison GuyHurst,16WestminsterClose,KempshottRise,BASINGSTOKE,Hampshire.(andalsoEditorof RG224PPEngland.TheAstronomermagazine) Phone&Fax: (+44)(0)1256471074
E-Mail: [email protected]@ast.star.rl.ac.ukCCDImagingAdvisor [email protected]’sTaleandNewsletterEditor JaniceMcClean
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14PictureGalleryCopyrightofallimagesbelongstotheObserver
2p_201703326_grhemann.
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Comet29p2017RichardMiles
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41p_20170325_grhemann
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42p_20170419_cschur.j
41p_20170428_0151_dgb
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43p_20161011_jchambo
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56p_20161001_0125_mjaeger
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2015er61_20170506_dpeach
2015er61_20170919_dpeach
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2015v2_20170301_jchambo
2015v2_20170409_0146_pcarson
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2015v220170518_2134_mjaeger
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2017o1_20171002_dpeach
2017_20171002_grhemann
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2017o1_20171015_rligustri
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411Endnote-TheEadwinePsalter
https://en.wikipedia.org/wiki/Eadwine_Psalter
https://commons.wikimedia.org/wiki/Category:Eadwine_psalter_-_Trinity_College_Cambridge_Library_R.17.1
Thebookisatrilingual,glossedpsalteriumtriplexmadeinChristChurch,Canterbury,inthemid-twelfthcentury.Itcontainsacalendar,tripleMetricalPsalms90:15-95:2,canticles,twocontinuouscommentaries,twoprognostications,amarginalimageofHalley'sComet(recordedin1147),adiagrammaticrepresentationofChristChurch'swaterworks,andafullpagevisualmemorialisationofEadwine.Atleast13scribesappeartohavebeenemployedintheconstructionofthismanuscript.
Thedatingofthemanuscripthasbeenmuchdiscussed,mainlyonstylisticgrounds(regardingboththescriptandtheillustrations),withinthebroadrange1130–1170.Onfolio10thereisamarginaldrawingofacomet,withanoteinOldEnglish(inwhichitisa"hairystar")thatitisanaugury;followingthecometof1066theEnglishevidentlytookcometsseriously.ThiswasthoughttorelatetotheappearanceofHalley'sCometin1145,butanotherof14May1147isrecordedintheChristChurchAnnals,andthe1145oneisnot.Therewerefurthercometsrecordedin1165and1167,sotheevidencefromastronomyhasnotsettledthequestion.Suchalargeundertakingwouldhavetakenmanyyearstocomplete;theAnglo-CatalanPsalterwasleftunfinishedinEngland,likemanyotherambitiousmanuscriptprojects.(ThankstoWikipediaandtothefreelibraryreproductionsofTrinityCollege,Cambridge).Thebookisstunning-dofollowthelinksaboveandtakeapeak.TheEditor
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