Carson Optical RP-300 Telescope User Manual


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UnderstandingCelestialMovement:
Inordertogetthemostenjoymentoutofyourtelescopeitisnecessaryto
knowthebasicsofhowcelestialobjectsmoveacrossthesky.Duetothero-
tationoftheearth,celestialobjectsappeartomovefromEasttoWestacross
thesky,muchliketheSun.Youwillnoticethismovementasanobjectin
yourtelescopeeldofviewwillslowlymoveacrosstheeldandoutof
view.Continuousadjustmentisneededtokeepanobjectintheeldofview.
This will be explained in more detail later.
Manypeoplechooseto“star-hop”whenusingatelescope,aquickandrela-
tivelyeasywaytostart.Thisisamethodofusingeasilyidentiablestars
andconstellationstoserveasreferencepointstondotherobjectsinthesky.
Amoreadvancedandprecisemethodoflocatingspeciccelestialobjectsis
byusingsettingcircles(Fig.3-16,17)locatedonyourequatorialmount(Fig.
2-10)tondthecelestialcoordinatesofthatparticularobject.
A Brief Overview of Celestial Coordinates:
Astronomersuseasystemof“celestialcoordinates”similartotheEarth’s
latitudeandlongitudesystemtohelplocateobjectsinthesky.Allcelestial
objectsaremappedona“celestialsphere”,animaginarysphereofarbitrary
sizeconcentricwiththeEarth.IfyouextendtheEarth’srotationalaxisto
innity,bothNorthandSouth,thepointsatwhichthisaxisintersectsthe
celestialsphereareknownastheNorthCelestialPoleandtheSouthCelestial
Pole.IfyouprojecttheEarth’sequatoroutwardtothecelestialspherethis
wouldbeknownasthe“CelestialEquator”.
Theequivalenttolatitudelinesonthecelestialsphereareknownaslinesof
“Declination”,or“Dec.”forshort.Theselinesaremeasuredindegrees,min-
utesandseconds.Declinationreadingsnorthofthecelestialequatorcarrya
“+”sign,whilereadingssouthofthecelestialequatorcarrya“-“sign.Ob-
jectslocatedonthecelestialequatorhavea0°0’0”Declination.TheNorth
CelestialPolehasa+90°0’0”DeclinationwhiletheSouthCelestialPolehas
a-90°0’0”Declination.ThestarPolarisislocatedveryneartheNorthCeles-
tialPoleandhasa+89.2°Declination.
Theequivalenttolongitudelinesonthecelestialsphereareknownaslines
of“RightAscension”or“R.A.”forshort.Theselinesaremeasuredinhours,
minutesandsecondsstartingatthe“zero”lineofR.A.whichpassesthrough
theconstellationPegasus.Thereare24primarylinesofR.A.locatedat15°
intervalsalongthecelestialequator.RightAscensioncoordinatesrangefrom
0hr0min0secto(butnotincluding)24hr0min0sec.
EverycelestialobjecthasacorrespondingR.A.andDec.coordinate.Given
the proper coordinates, you can use the setting circles on your telescope
mounttolocateanycelestialobject.Thecoordinatescanonlybeusedifthe
telescopeisrstalignedwiththeNorth(orSouth)CelestialPole.
Polar Alignment:
If the telescope is accurately aligned with the celestial pole, very little dec-
linationadjustmentwillbenecessarytotrackacelestialobject.Mostofthe
trackingcanbedoneusingtheRightAscensioncable(Fig.1-8).
To line up your telescope with the pole:
•Makesuretheequatorialmountislockedinthe“home”position,
meaning that the optical tube assembly is parallel to the correspond-
ing portion of the mount below it and that the declination axis is
straightupanddownwiththecounterweight(Fig.2-13)init’s
lowestposition.Forreference,theequatorialmountinFig.2isin
the home position.
•Loosentheequatorialmountlockingscrew(Fig.3-21)sothatthe
entiretelescope(withmount)rotatesfreelyonthetripod.
•RotatetheentiretelescopeuntilthepolaraxispointsdueNorth.If
you are not sure which direction is North, locate Polaris and point the
polar axis towards it. Polaris is less than one degree away from the
Celestial North Pole and is accurate enough for polar alignment.
•Ifneeded,levelthemountbyadjustingthetripodlegsaccordingly.
•Determinethelatitudeoftheareayouarein.Usethelatitudeturn
screws(Fig.3-19)totiltthetelescopeuntilthepointerindicatesthe
correctlatitudeonthelatitudedial(Fig.3-18).
•Thennetunethelatitudeturnscrews(Fig.3-19)untilPolaris
appearsinthecenterofyourtelescopeeldofview.
•DonotmovethetelescopeinR.A.orDec.whilepolaraligning.
Theseadjustmentsshouldremainlocked.
•IfyouliveintheSouthernHemisphere,youshouldfollowthese
stepsbutpointthepolaraxisdueSouthandlocateSigmaOctantis
instead of Polaris.
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