Table of Contents - WorldWide...
Transcript of Table of Contents - WorldWide...
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TableofContentsIntroduction
ConstructionoftheDomeSupport
ToConstructaSmallerDomeSupport
TheDomeSpecificationUtility
ConstructionoftheDome
ToConstructaSmallerDome
AddingVentilationandPower
AddingSeatingandCarpeting
SettinguptheProjectorandMirrors
HighQualityMirrors
RunWorldWideTelescope
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WorldWideTelescopePlanetariumThisdocumentdescribeshowtobuildaplanetariumforusewithWorldWideTelescope.
TheplanetariumprovidesschoolsandothergroupswithagreatwaytovisualizethepanoramicviewoftheuniverseprovidedbyWorldWideTelescope.
Theplanetariumdescribedhereisjustunder12.5feetindiameter,andjustover9feettall.Sothefirststepisfindingasuitablelocationforit!Thematerialsusedarenotsuitableforanoutsidelocation,sothelocationshouldbeinside,levelanddry.Alternativemeasurementsaregivenforasmaller(9feetdiameter)planetarium,thoughalltheimagesinthisdocumentareforthe12.5feetmodel.Measurementsaregivenininchesasthisisthemostusedunitforpackingmaterialsandparticleboard,whicharethemainconstructionmaterialsused-48inchwidecorrugatedcardboard,and48inchwideparticleboardpanelingarebotheasytocomeby.TheDomeSpecificationUtilitycanbeusedifmetricmeasurementsarepreferred.
Oneofthemostinterestingfeaturesofthedomeisthatitistiltedatanangleof20degrees.Thismakesconstructionalittlemorecomplex,butthedesigngivesamuchbetterexperience.TheideaisthatstudentswillfeeltheyaretravelinginaspaceshiptowardsaplanetsuchasSaturn,whichwouldnotbethecaseiftheviewwasvertical.Thetiltalsogivesroomforareasonablepairofdoors,androomfortheprojectorandmirror,withoutexcessiveheight.Thecosttothisthoughisthatconstructingthedomesupportisasinvolvedasconstructingthedome(ageodesichalf-dometobeprecise)itself.
Costsformaterialsvary,howeverareasonablebudgetforthedomeandsupportcomponentsisUS$700.00at2009prices.Inadditiontothisasphericalmirrorisrequired,optionallyaflatsecondarymirror,andasuitableprojector.Toolsarenotincludedinourbudgeting,astheyarecommonhouseholdtoolsthatmanyteachersandparentswillownalready.AlaptoprunningWorldWideTelescopeisobviouslynotincludedinthebudgetingeither.
Notethatanumberofthetasksinvolvetheuseofcuttingtoolsandpowersaws,soresponsibleadultinvolvementintheprojectisessential.
Introduction
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ConstructionoftheDomeSupportConstructionofthedome,andthedomesupportcanlargelyproceedinparallel.Toconstructthedomesupport,gothroughthefollowingprocedure:
1. Purchasethenecessarymaterials:
5sheetsofparticleboard,orplywood,96inchesby48inches.17feetof2x3inchwood.20feetof2x2inchwood.120woodscrews(1or1.25inch).20heavydutyclipstoattachthedometothesupport.10lengthsof1x1.5inchwood,eachpieceexactly48incheslong.Twohingesandonehandleperdoor.Black2inchwidetape.
2. Assemblethenecessarytools:
Mitersaw,orcompoundmitersaw.Portablecircularsaw.Handsaw.Safetygogglesandmasks.Sandpaper.Drill.Mattblackpaint.Chalkline,orlongmeasuringrulers.Othertoolsmaybehelpful:files,screwdrivers,planes,clamps,sawhorses,andsoon.
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3. Understandtheshapesinvolved.Boththedomeanddomesupportarebasedonadecagon-10sidedfigure-showninthefollowingdiagram:
Thedomeisadecagon-eachsideis48inches.
Eachinsideangleis144degrees.
Thefronttobackdiameteris147.72inches.Thesidetosidediameteris155.32inches.
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Aftertilting20degreestheplanviewofthesupportbecomesanelliptical,ratherthanregular,decagon.Thetopedgeofeachpanelis48inches,butthewidthsoftheotherpanelsvary-48inchesfortherectangularpanels.but47.02inchesand45.4inchesfortheangledpanels.
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Thedomesupportprofile.
4. Cutout,orhavecutoutforyou,the10sidepanelsin0.5inchparticleboardorplywood.The10panelsare:
1at48inchby12inchrectangle.2at47inchbase,withonesideat12inchesandoneat215/8inches.2at453/8inchbase,withonesideat215/8inchesandoneat371/4inches.2at453/8inchbase,withonesideat371/4inchesandoneat527/8inches.2at47inchbase,withonesideat527/8andoneat621/2inches.1at48inchby621/2inchrectangle.
5. Lightlysandandsmooththeedgesofthewood.
6. Cutout20woodenconnectingblocksforthepanels,from2x3(orsimilar)wood.Becauseofthetilt,theblocksarenotallexactlythesamesize.Thethicknessofthewoodisnotthatimportant-itistheanglesthatarecritical.Themoreaccurateyoucancuttheanglesthelessadjustmentwillbenecessarywhenthedomesupportismatchedtothedome.Mostmitersawswillnotcutatsuchanacuteangleas17degrees,sofirstmakeatemplateblockwithacutat73degreesusingamitersaw,thentocutthe17degreeangleclampthetemplateblockinplace,carefullyplacetheactualblock,andthena90degreecutwillgivethedesiredresult.Notethatthetwocutsoneachblockneednotmeetatanexactpoint,thoughtheycan.Ashortflatsectionbetweenthetwoangledcutsisnotaproblem.Withasimple10inchmitersawblockwidthsshouldbechosenthatthesawcancutrightthrough-whichlimitsthethicknessto2.5inchesorso.Acompoundmitersawwillgivegreaterflexibility.Beforestartingontheangledcuts,cutthe2x3woodinto10inchlengths(20areneeded).
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BlockA.Eightoftheseareneeded.Aftercuttingthemoutmarkthemwithan"A",astheanglesofallblocksareverysimilar.
Theexactangleshereare72.85and17.15degrees.
Notethe73degreetemplateblockhasbeenmarkedandclampedtothemitersaw.
BlockB.Eightoftheseareneeded.Markthesewitha"B".
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Theexactangleshereare71.7and18.3degrees.
Makea72degreetemplateblocktostartwith.ThencutouteightBblocks.
BlockC.Onlyfouroftheseareneeded.Markthemwitha"C".
Theexactangleshereare70.9and19.1degrees.
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Makea71degreetemplateblocktostartwith.ThencutoutfourCblocks.
7. Takeoneofthepanelsmarked"Door"intheprecedingimages.Cutoutarectangulardoorshape,andfithingesandahandleontheoutside.Thedoorwillopentotheoutside,sothereisnoneedforahandleontheinside.
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Thedoorheightwillbemoresuitableforchildrenthanforadults.
Ifalargerdoorisrequiredconsideraddinganequalamounttotheheightsofallthesidepanels.
Inordertohaveafullsizedoorthewholestructurecanberaisedbymakingthelowersideofthedomesupporthigherthan12inches.However,tohavea6footdoorthelowersidewillneedtobearound36inches,addingafurther2feettotheheightoftheplanetarium.
Addaseconddoortotheothersideofthedomesupport-toprovidebothan"In"andan"Out",andafireescape.
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Notethe2x2inchwoodusedtostrengthenboththesideofthedoorframecontainingthehinges,andacrossthebottomofthedooropening.Usescrapsofwoodtostrengthenthehingesonthedooritself.
Forarectangulardoor,considerusingapoweredcircularsawtocutoutmostofthedoor,butuseahandsawtofinishoffthecuts.Fortheroundeddoorshowninthepicture,useahandheldjigsawtocutouttheshape,aftercarefullydrawingthearconthepanel.
Therectangulardoorshowninsomeoftheimagesisquiteshort-duetoheightrestrictionsintheassemblyareafortheprototype-whichisthereasonwhytheroundeddoorwasmadeasanimprovementtomakealittlemoreheadroom.
8. Usingshortscrews(1.5inchwoodscrews,orsimilar)assemblethedomesupportbyscrewingoneblocklowdownoneachpanel,andonenearbutnotatthetop(atleast1inchshortofthetopoftheshortestofthetwopanels).Pilotholesforthescrewsshould
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bedrilledfirst,andthescrewsdrilledintoplacebutnottightenedtothemaxuntilthewholesupportisinplace.
NotethepositionsoftheA,BandCblocks,andthattherearetwoofthemperjoint.
Aplanviewofthedomesupportshowsittobeanellipticaldecagon.
Thefirstblock.UseanAblocktoconnecttheshortestrectangularpanelwiththeshortestangledpanel.
Nextaddthesecondblocktothisjoint.
Thenaddthematchingshortestangledpaneltotheotherside.
Theprogression.Movingleftandrightassemblethedomesupportpanelsfromtheshortesttowardsthetallestpanel.
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Unevennessinthefloormightcausesomeminoralignmentissues.Ifthisisthefinallocationofthedome,thenensurethatitisasstableasitcanbe.Minormismatchesintheheightsofthepanelsisdealtwithwhenscrewingintheledges.
Notethepositionsofthetopjointblocksafewinchesbelowtherim.
1. Ontheoutsideofthetopedgeofeachpanelscrewinalengthof1x1.5inchwood(orsimilar)thatisexactly48incheslong.Thisshouldcreatealedgeallthewayroundtheoutsideofthedomesupport.Accuratelyaligntheledgewiththetopofthepanels,butmoreimportantlywiththeprecedingledges,sothatthesupportingsurfaceforthedomedoesnotchangeheightfromtheendofonesidepaneltothestartofthenext.Startatthetallrectangularpanel,andusing3screwsperledge,carefullyworkyourwayaroundthedomesupport.
2. Usinga2inchdiameterholedrillingbit(orsimilar)-drilloutagridof3x4or4x4holestobeusedtoventtheplanetarium.
Asmallextractorfanwillbeaddedtothedomesupportatalaterstage,toprovidesomeairflow.
3. Cleanthedomesupportareaofallsawdust,screws,andanyleftoverpiecesofwood.
4. Painttheinsideofthedomesupportaflatmattblack.
Makesuretopaintaroundalltheblocks,thedoorsupports,andthetopoftheledges.Alsopainttheinsidesoftheventholes,andtheedgesofthedoors.Trytopainttothebottomofeachpanelwithoutpaintingtoomuchofthefloor!Useplastictarps,orsimilar,toprotecttheflooringifnecessary.
5. Painttheoutsideofthedomeanycoloryoulike.
6. Sealallthegapsontheoutside.Nolightshouldgetinthroughthejointsbetweenthepanels,noraroundthesidesofthedoor.Useathicktapetosealthejoints.Thedoorismorecomplicated,considerattachingablackfeltcurtainontheinsidetoblockoutanylight.
ToConstructaSmallerDomeSupport
Toconstructadomesupportusing36inch,ratherthan48inch,sides,usethefollowingtableofmeasurementsforthepanelsizes.Thiswillcreateadomesupportforadomethatisjustover9feetindiameter.Thedomesupportwillhaveasidetosidediameterof116.5inches(about9.5feet)andafronttobackdiameterof104.1inches.Obviouslyuse36inch
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longledgesections,buttheblocksthatfitthedomesupporttogetherhaveexactlythesameanglesasforthe48inchsideddomesupport.Notethatthedoorforentrywillnowbequiteshort,soconsideradding12inchestotheheightofallthepanels,ifyourlocationhastheheadroom!
Number Sizes
1 36inchx12inchrectangle.
2 351/4inchbase,oneside12inches,othersideis191/4inches.
2 34inchbase,onesideis191/4inches,othersideis3015/16inches.
2 34inchbase,onesideis3015/16inches,othersideis4211/16inches.
2 35.26inchbase,onesideis4211/16inches,othersideis497/8inches.
1 36inchx497/8inchrectangle.
TheDomeSpecificationUtility
Clickonthelinkbelowtorunautilityprogramthatwillcalculatethetriangleandpanelsizesrequired,giventhreeinputs:
1. Thelengthofthesidesoftheequilateraltriangles(triangleA).2. Theheightoftheshortestpanelinthedomesupport.3. Thetiltangleindegrees.Though20degreesisrecommended,otheranglescanbe
used,andthesoftwarecanbeconfiguredtomatch.
Notethattheutilityrequiresscriptstoberun,soifyougetasecuritywarning,besuretoAllowBlockedContent.Notealsothatanglesdonotchangewiththesizeofthedome.
DomeSpecificationutility
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ConstructionoftheDomeToconstructthedome,gothroughthefollowingprocedure:
1. Purchasethenecessarymaterials:
40sheetsofcorrugatedcardboard,ideallywithonesidealreadywhite,48x48inches.Purchaseanextraoneortwoifmistakesmightbemade.Alternativelyslightlyfewersheetsareneededwith48x96inchcardboardsheets(asthreeofthesmallertrianglescanbecutpersheet)butthereisatransportissuewithsheetsofthissize!Soeitherbuy4048x48inchsheets,or1548x96inchsheets,plusafewextraasspares.165large(2ormoreinchwide)paperbinderclips.Thisprovidesthreeclipsperjoint.Blackpapersheetstotaling48incheslongby110incheswide.Mattflatgrey(notwhite)paint.
2. Acquirethenecessarytools:
Sharpknife.Longmetaledgedscale.Sharppoint,string,andpencil.Paintbrushes,cleaningmaterials,newspaper.
3. Verycarefullydrawoutandthencutoutthetemplatetriangles.Twosizesoftrianglearenecessary,labeledasAandBinthefollowingdiagrams:
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Usethefullwidthofthe48inchsheets.
Todrawthetriangleyoucanuseasharppointwithastring48incheslong,anddrawtwoarcs.Wherethearcsintersectisthetipofthetriangle.Alternativelycalculatetheheightofthetriangle(41.57inches)-measurethisalongbothedgesofthecardboard,thendrawalinefromonesidetotheother,andmarkthecenter-24inchesalongtheline.
Aftercuttingoutthetemplate,10trianglesoftypeAareneeded.
Notethatthetriangleis48inchesonallsides,andthattheflapsareinadditiontothis.Thisispossibleonasheetofcardboardonly48incheswidebyhavingthetaperedflapsshownatthecorners.
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Aftercuttingoutthetemplate,30trianglesoftypeBareneeded.Thiswillrequire3048x48inchsheets,or1048x96inchsheets,asthreetrianglescanbecutfromthelargersheet.
13/16thsisagoodapproximationfor.82inch.Theheightofthetriangleis34.25inches.
Notethatthetriangleis48inchesononeside,and41.82ontheothertwosides,andthattheflapsareinadditiontothis.
4. Wheneachtriangleiscutoutlabeltheoutside(notthewhitesideifwhite-sidedcardboardisused),withthelettersAorB.
5. Markthelineswheretheflapsneedtobefoldedwithapencil,thenuseadullpointlikeaball-pointpentoscorethecardboardwithoutcuttingittomuch.Practiceonsomescrapstogainsomeexpertisefirst.Scorethecardboardtrianglesaccuratelyandfoldtheflapsout.
6. Doublecheckyouhavethecorrectquantities:10oftriangleA,30oftriangleB,notincludingthetwotemplatetriangles(whichshouldbestoredseparatelyandnotpainted-incaseyouneedtoredooneormoretriangles).
7. Atthisstagetheinsideofthetrianglesshouldbepaintedaflatmattlatexgrey.Ifwhitecardboardisusedthisshouldnottakemorethanonecoatofpaint.Makesurethatthepaintingisdoneinaventilatedarea,andappropriatebreathingmasksareused.Brown
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cardboardmaytakeasecondcoatofpaint.Althoughthetemptationistouseapurewhitepaint,thiswillreflecttoomuchoftheprojection.Aflat,lightgreyshouldgivethebestresults.Itisnotnecessarytopainttheflapscompletely,butpaintovertheedgesofthetrianglesandintotheflapareatoensuregoodcoverage.
Paintingisfun-thoughisusuallydoneonaflatlevelsurface!
8. Afterthecardboardispainteditmaybowtovaryingdegrees.Whenthepaintisdryconsiderstackingthetriangles,perhapswithhalffacingtheoppositedirection,withaweightcarefullyplacedontoptohelpcounteractthebowingeffectofthepaint.Inanycasewhentheflapsareturnedoutthiswilltendtoflattenoutthetrianglesagainconsiderably,sothebowingisnottheseriousissuethatitmightfirstlook.
9. Optionalstep.Makeblackshadestoblockoutlightalongtheedgesofthepentagon.Thereare55sidesinternaltothedome,and10sidesaroundthebase.The55internaledgesareamixof48and41.8inches.Cutoutstripsofblackpaperlongenoughthattwooverlappingpieceswillcoverthewholeedge.Obviouslyshorterpiecescanbeusedforthe41.8inchsides.Theinternalstripsshouldbe2.25incheswide(assumingcardboardthatisoneeighthofaninchwide),withafoldat1and1.25inchesalongtheirfulllength.Ifthecardboardyouhaveusedisnotoneeighthofaninchwide,thenthethicknessofthesquarefoldsshouldsimplybetwicethethicknessofthecardboard.Thefoldsneedtobeverystraightfortheshadestofitneatlyontotheedges.Ifasinglefoldisusedtheshadeswilltendtokeepthebinderclipsoutfromthejoin,whichweakensthestructureandispronetoerror.Thereasonwhythisstepisoptionalisthattogetstraightfoldededgescanrequirepaperfoldingequipmentthatmightnotbereadilyavailable.Theimagesshowafoldingmachineandthecompletedshades.Fortheexternal10sidesaroundthebase,thepaperstripsshouldbe3incheswide,foldedat1and2inchesalongtheentirelengthofthestrip.
Apaperfoldingmachineisthebestapproachtogettingverystraightfolds.
Ifsuchafoldingmachineisnotavailable,tryotherlongstraightedgessuchasametalruler.
Firstmarkasheetofblackpaperwhereitneedstobecutandfolded.Thenfoldthesheettwicetocreatethequarterinchsquareend.Thencutoutthestrip.Repeatuntileveryedgehastwoshades.
Theimageshowsaquarterinchfoldforthetriangles,andaoneinchfoldforthebase.
Apentagonwithshadesattached.
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10. Timetogetoutthosepaperclips.StartwithallthetriangleBs.Theseareusedtomakethepentagons.VerycarefullyaligntheshorteredgesoftheBtriangles,placeoneormoreoftheblackshadesalongeachjoint,andcliptogetherapentagon.Notethatjoiningthelastsidewillliftthecenterofthepentagonabout9inches.Ensurethereisenoughspacearoundsothatthesepentagonsarenotsteppedon.
Theoutsideedgesofthepentagonshouldallbethelonger48inchsides.
The30triangleBsshouldbeassembledintosixpentagons.
11. Withalotoflaborassistance(aminimumoffivepeopleworkswell),assemblethedomeintheordershowninthefollowingdiagram:
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Notethatthecentralpolygonistheverylastpiecetobeassembled.Thedomewillbequitefloppyuntilthisisdone,andalotofhandsarehelpfulatthisstage.
Whenbuildingthedometrytoalignthepointsandedgesasaccuratelyaspossiblebeforeproceedingtothenext.
Thecriticalstageinassemblyishavingenoughhandsinsidethedometocompleteallbutthetoppentagon.
Becauseofthedifficultyinclippinginthetoppentagon,considerhavingsomeonestandonasteppingstoolandheldinplacebyasecondperson,whilstthefirstleansoverthedomeandclipsinthefivelastsides.Thepeopleontheinsideneedtosupportboththelasttoppentagon,andallthesides-atthesametime.
Onlywhenthelasttoppentagonisclippedintoplacedoesthedomebecomeself-supporting.
12. Admireyourwork!Thedomeshouldnowbereasonablyrigid.
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13. Ensurealltheflapsoftheloweredgearebentout,andcarefullyliftthedomeontothesupport-witheachofthe10cornerssupportedbyanassistant(hencetheneedforaminimumoffivepeople).Donotliftthedomeatanytimeotherthatatitscorners.Obviouslythecornersand48inchedgesofthedomeshouldmatchtheledgesofthedomesupportexactly.
14. Usethe20heavydutyclipstoattachthedometothesupport,twoclipsperside.
Theheightofthedomewhenitisonthefloorandbeforeitistiltedisjustunder6.5feet.Afterthe20degreetilttheheightisabout6feet.Addtothistheheightofthecenterofthedomesupport(justover3feet),andtheheightoftheplanetariumisafewinchesover9feet.
15. Openupadoorandgoinside!
ToConstructaSmallerDome
Toconstructadometofitthe36inchsidedomesupport,triangleAshouldbeanequilateraltrianglewith36inchsides.TriangleBshouldbeanisoscelestrianglewitha36inchbaseandtwosidesof313/8inches.
Theheightofaplanetariumofthissizeisaround7feet.Thefollowingimagesshowstherelativesizesofthedomes.
</th>|48inchtriangleplanetarium|36inchtriangleplanetarium||:--|:--|
AddingVentilationandPowerAddingventilationtotheplanetariumwillmaketheexperiencemorepleasantformostpeople.Electricpowerwillbeneededtopowertheexternalfan,andalsoobviouslytopowertheinternalprojector.
1. Purchaseoracquireasmallextractorfan(thefanmustbecapableofgoingintoreverse-toextracttheair-ratherthanjustblowwarmair).
2. Usingblackfoam-board,orasimilarmaterial,constructaboxasshownintheimagebelow.
Picsoffanandbox
1. Powerupthefanandcheckthattheventilationsystemworks.2. Runablackpowercable(25,30oreven50feet)throughoneoftheventilationgrill
holesandupandoveroneofthedoorssothatthepoweroutletsareavailabletotheprojectorthatwillbesittingonashelfbetweenthetwodoors.Considerusingsafety
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hooks(cuphooksthatclosewithaspring),orsimilarsmallhooks,toguidethepowercable.Ensurethatitdoesnotcrosstheflooratanystageinsidethedomesupport,whereitcouldbetrippedon.,andfollowsasafepathtothepoweroutletoutsideoftheplanetarium.Ifthepowercableorhooksarenotblack,thenconsiderpaintingthehooksandcoveringthecableinsidetheplanetariumwithblacktape.
Thecableinthisimagehasbeenleftredtoshowitscourse.Coveringthecablewithblacktapefortheinsidesectionensuresminimalreflectivity.
AddingSeatingandCarpetingIdeallytheviewersinsidetheplanetariumwillbeseatedentirelybelowthebaselineofthedome-thisistoensurethatnopartofthemblocksthereflectionfromthemirrorontothedomesurface.Inpracticethismaybedifficulttoachieve,especiallyifheightwasanissueduringconstruction.Thesuggestedlayoutistolayblackcarpettilesacrossmostoftheflooroftheplanetarium,withperhapsafewseatssetatthebackneartheprojector.Shorterviewerssitatthefrontandmiddleoftheplanetarium,onthecarpet,tallerviewerscanusetheseatsattheback.Theexactlayoutdependsonthenumberofviewersyouplantoaccommodateatanyonetime-allcarpetingandnoseats,orallseatsandnocarpeting,areobviouslyoptionstoo.
Theseats,similartoallitemsunderthedome,shouldbeasmattblackaspossible.
SettinguptheProjectorandMirrors1. Themirrorneedstobeahalf-domesphericalmirrorasshownintheimagebelow.High
QualityMirrors
Experimentingwithdifferentsizesofsphericalmirror.Thesmaller,approximately9inchradius,workedwellinourtests.
1. Theprojectorshouldprovideashighadefinitionaspossible.IdeallytheprojectorshouldbecapableoffullHD,1920x1080pHDforexample(whichgivesa16x9aspectratio).SuchaprojectorwillrequireaDVIorHDMIcable
ADVIcable.
2. Themirrorshouldbeplacedinthedirectcenteronthehighestsideofthedomesupport,angleddownwardsatanangleof20degrees,anditsbaseshouldbeatthesameheightatthebaseofthedome.Thesupportforthemirrorcanbemadeoutofwood,cuttogivea20degreeangle,orotheroptionscanbeusedtoprovidesomefine
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adjustmentshoulditbenecessaryorhelpful.Intheimagebelowasecondtierkeyboardsupport(foramusickeyboard)hasbeencutanddrilledtoprovideamirrorsupportthatcanbothtakeavariablesizeofmirror,andhavetheangleofthemirrorfinelyadjusted.
3. Theprojectorneedstobeplacedpointingupatthemirrorsothattheimageisreflectedoffthemirrortofillthedome,butnotthedomesupport.Forthisasolidsupportsystemisneededthatwillsafelyholdtheprojectoratanangleofabout20degrees,andprovidefineturningadjustment.Onegoodsolutiontothisistouseasolidmusicorconductorsstand(asshownintheimagebelow).Thesecanbefoundreasonablycheaply(around$50)andaresurprisinglysturdy.Findonethatenablesadjustmentinbothsidetoside,andupanddowndirections,andisvariableinheightfromaround24to40inches.
Primaryprojection.
Eventhoughamusicstandisdesignedtoholdjustpaper,asturdyonecaneasilysupportandholdaprojectoratanangle.
4. Analternativetotheprimaryprojectiondescribedinstep4,istouseasecondarymirror.Useofasecondarymirrorhastheadvantagethattheprojectorandsupportarenolongernearthecenterofthedomeusingupvaluablespectatorspace.Howeverthedownsidetousingasecondarymirroristhatitinvolvesadditionalcost(ofthesecondarymirroritself,andsomeshelving),andcomplicatesthealignment-theprojector,secondarymirror,andsphericalmirrornowallhavetobealignedsimultaneouslyandcorrectly.
Secondaryprojection.
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Tousethesecondarymirrormethodofprojection,firstinstallashelvingsystemthatenablesavariationintheheightoftheprojector.Theshelfitselfshouldbeabout24incheswideand13inchesdeep-thoughthisdoesobviouslydependonthesizeoftheprojectoryouintendtouse.
Placetheprojectorontheshelfsothatthelensiscentered-whichiswhytheshelfshouldbe24incheswide,andnotsimplythewidthofaprojector.
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Thesecondarymirrorshouldbealignedatthetopofthemusicstand.HeavydutyVelcro(orsimilar)canbeusedtoattachthemirror.
Thefinealignmentofthethreemainelements(projector,secondarymirror,sphericalmirror)willinvolvesomeminoradjustmentstotheanglesofeachtogetacompleteimageprojectedontothedome.
Notehowclosethesecondarymirroristotheprojector.Justenoughroomisneededsothatthereflectedimageclearstheprojectoritselfandfindsthesphericalmirror.
Thissystemfreesupthecenterofthedomequitewell.
HighQualityMirrors
Mostmirrorsreflectlightfromtwosurfaces,theinsideandoutsidefacesoftheglassorplastic.Unfortunatelythismeansthattherewillbetwoimagesinviewonthedomeforeachsingleobjectinthesimulatedsky-theintendedimageandasecondfainterimageslightlyoffsetfromthefirst.Thisproblemisdoubledifasecondarymirroralsowithtworeflectivesurfacesisused-inthiscasetherewillnowbefourimagesonthedome,theintendedoneandthreefainterghostimages.Thisproblemcanbeeliminatedwiththeuseofhighqualityfirstsurfacemirrors.Thesemirrors,bothflatandspherical,haveonlyonereflectivesurface,soevenwhenasecondarymirrorisusednounwantedghostimagesappearonthedome.Ofcoursetheissuehereiscost,firstsurfacemirrorsareafewtimesmoreexpensivethannormalmirrors.
Theuseoffirstsurfacemirrorsisrecommendedifyourbudgetallows!
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RunWorldWideTelescope1. Connectalaptopcomputertotheprojector,andifpossibletotheinternet.Withoutan
internetconnectionyouwillberestrictedtoshowingthetoursandcollectionsfilesthatarestoredlocallyonthelaptop,sointhiscaserunallthetoursyoumightneedonce(whichstoresthemlocally)whilstconnectedtotheinternet,beforeremovingtheconnectionandmovingtothedome.
2. RuntheWorldWideTelescopeWindowsClientonthelaptop.TheWebClient(basedonSilverlight)doesnotcurrentlysupportthedomewarpingsoftware,somakesureyouareusingthedownloadedWindowsClientversion,andthattheversionnumber(whichcanbeverifiedintheAboutWorldWideTelescopedialog)is2.6.2.1orlater.ItisrecommendedthatyouuseaWindowsbasedlaptop(WindowsXP/Vista/7)forsimplicity,butyoucanuseaMaclaptopwithaWindowspartition.
3. SelectFullDomefromtheViewmenu,thenselectDomeSetuptobringupthefollowingdialog:
Formostmodernprojectorstheaspectratiois16:9,sosettheDomeTypetoMirrordome16:9.IfyouareusinganolderVGAprojector,thentheaspectratiomaywellbe4:3,sosetthisvaluetoMirrordome4:3.RefertotheConfigurationsectionoftheWorldWideTelescopeUserGuidefordetailsifyourprojectorisneitherofthese.
SetDomeTiltto70percent.Thisvaluecontainsthecenterofinterestinverticaldegrees.
Forhighresolutionprojectors(1920x1080orsimilar)selectLargeTextures,otherwiseleavethisunselected.
ClickOK.
4. IntheFullDomemenuensureFullDomehasatickbesideit.
5. Ifyouwishtocontrolthepresentationbylookingatthelaptop,thenyouaregoodtogo-themousemovementsandclicksonthelaptopscreencontroltheview.Ifyouwishtocontrolthepresentationbylookingatthedomeprojection,thenselectDetachMainViewtoSecondMonitor.ConsiderusinganXBoxcontrollerinthislattercase,asinputcontrolhasnowbepassedtothedomeviewandcontrollingthepresentationwithamousecanbeawkward.
6. Inviteyourstudentsandpeers!
RunWorldWideTelescope
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