Celestron Telescope CR 150 HD User Manual

The CR-150 HD

6" Refractor

Model #21017

INSTRUCTION MANUAL

...........................................................................................................

Observing the Moon .......................................................................................................................36

ObservingthePlanets .....................................................................................................................37

Using the Lens Cap Aperture Stop.............................................................................................37

ObservingtheSun ..........................................................................................................................37

Observing Deep-Sky Objects...........................................................................................................38

Using the Setting Circles ....................................................................................................38

StarHopping .....................................................................................................................39

ViewingConditions ........................................................................................................................41

Transparency ....................................................................................................................41

Sky Illumination ...............................................................................................................41

Seeing ...............................................................................................................................41

CELESTIAL PHOTOGRAPHY .................................................................................................... 4 3

Short Exposure Prime Focus...........................................................................................................44

Piggyback ......................................................................................................................................46

ProjectionPhotography ..................................................................................................................48

TELESCOPE MAINTENANCE.................................................................................................... 4 9

CareandCleaningoftheOptics.......................................................................................................49

OPTIONAL ACCESSORIES .......................................................................................................... 5 0

THE MESSIER CATALOG............................................................................................................ 5 3

LIST OF BRIGHT STARS .............................................................................................................. 5 6

FOR FURTHER READING ........................................................................................................... 5 7

Table of Contents

•

iii

I N T R O D U C T I O N

WelcometotheCelestronworldofamateurastronomy! Formorethanaquarterofa

century,Celestronhasprovidedamateurastronomerswiththetoolstoexplorethe

universe. ThelineofCelestronrefractorscontinuesinthisproudtradition. Each

telescopeismadeofthehighestqualitymaterialstoensuredurabilityandstability.

And,yourCelestronrefractorisversatile —itwillgrowasyourinterestgrows. All

thisaddsuptoatelescopethatwillgiveyoualifetimeofpleasurewithaminimal

amountofmaintenance. Allyouneedtodoistakethetimetofamiliarizeyourself

withyourCelestrontelescopeanditsoperation.

•

Introduction

How to Use This Manual

This manual is designed to instruct you in the proper use of your Celestron

refracting telescope. This includes assembly, initial use, and long term operation

and maintenance. There are four major sections to the manual. The first section

covers the proper procedure for setting up your Celestron refracting telescope.

Thesecondsectioncoversbasicoperationsthatarecommontoalltelescopes. This

includesattachingtheaccessories,focusing,aligningthefinderscope,andtaking

yourfirstlook.

Thethirdsectiondealswiththebasicsofastronomyandusingyourtelescopefor

astronomicalviewing. Thisincludespolaralignment,aligningthesettingcirclesand

usingyourCelestronforastronomicalobservations,bothvisualandphotographic.

Thelastmajorsectionisontelescopemaintenance,specificallyoncareandcleaning.

Inadditiontothemajorsectionslistedabove, thereisalistofoptionalaccessories

for all models of Celestron refractors. This includes a brief description of the

accessory and its purpose.

Finally,thereisalistofcelestialobjectsvisiblethroughyourCelestrontelescope.

Includedarethecoordinatesforeachobject,itsbrightnessandacodewhich

indicates object type. In addition, there is a list of bright stars that can be used for

aligning the setting circles on the CG-5 equatorial mount.

Youshouldkeepyourrefractormanualhandyuntilyouhavefullymasteredyour

telescope’soperation.

YourCelestronrefractorisdesignedtogiveyouhoursoffunandrewardingobserva-

tions. However, thereareafewthingstoconsiderbeforeusingyourtelescopethat

willensureyoursafetyandprotectyoureyesandyourequipment.

AWordofCaution!

WARNING !

NEVERLOOKDIRECTLYATTHESUNWITHTHENAKEDEYEORWITH

ATELESCOPE. PERMANENTANDIRREVERSIBLEEYEDAMAGEMAY

RESULT.

NEVERUSEYOURTELESCOPETOPROJECTANIMAGEOFTHESUN

ONTOANYSURFACE. INTERNALHEATBUILD-UPCANDAMAGETHE

TELESCOPE AND/OR ANY ACCESSORIES ATTACHED TO IT.

NEVERUSEANEYEPIECESOLARFILTERORAHERSCHELWEDGE.

INTERNALHEATBUILD-UPINSIDETHETELESCOPECANCAUSE

THESEDEVICESTOCRACKORBREAK,ALLOWINGUNFILTERED

SUNLIGHTTOPASSTHROUGHTOTHEEYE.

NEVERLEAVETHETELESCOPEUNSUPERVISED,EITHERWHENCHIL-

DREN ARE PRESENT OR ADULTS WHO MAY NOT BE FAMILIAR WITH

THECORRECTOPERATINGPROCEDURESOFYOURTELESCOPE.

NEVERPOINTYOURTELESCOPEATTHESUNUNLESSYOUHAVETHE

PROPERSOLARFILTER. WHENUSINGYOURTELESCOPEWITHTHE

CORRECTSOLARFILTER, ALWAYSCOVERTHEFINDER. ALTHOUGH

SMALLINAPERTURE,THISINSTRUMENTHASENOUGHLIGHTGATH-

ERINGPOWERTOCAUSEPERMANENTANDIRREVERSIBLEEYE

DAMAGE. INADDITION, THEIMAGEPROJECTEDBYTHEFINDERIS

HOTENOUGHTOBURNSKINORCLOTHING.

Introduction

•

The Refractor Optical

System

Developed in the early 1600s, the refractor is the oldest telescope design. It

derives its name from the method it uses to focus incoming light rays. The

refractor uses a lens to bend or refract incoming light rays, hence the name (see

Figure 1-1). Early designs used single element lenses. However, the single lens

acts like a prism and breaks light down into the colors of the rainbow, a phenom-

enon known as chromatic aberration. To get around this problem, a two-element

lens, known as an achromat, was introduced. Each element has a different index of

refraction allowing two different wavelengths of light to be focused at the same

point. Most two-element lenses, usually made of crown and flint glasses, are

corrected for red and green light. Blue light may still be focused at a slightly

different point.

Figure 1-1

This cross sectional diagram shows the light path of a classical two-element refractor.

The Mount

In the world of astronomy, there are basically two different types of mounts;

Altazimuth and equatorial. Both derive their names from the axial motion of the

mount. The Altazimuth moves vertically (altitude) and horizontally (azimuth)

relative to the horizon. The equatorial mount has its axis of rotation tilted so that

it can be aligned with the Earth’s axis of rotation. When this is done, the telescope

(when fitted with an optional clock drive) can track the stars. The directional

movements on this mount are North/South and East/West. The Celestron CR-

150 HD, 6 inch refractor uses a German equatorial mount called the CG-5 mount.

•

Introduction

A S S E M B L I N G Y O U R C R - 1 5 0 H D

AT POLARIS C

The CR-150 HD (#21017) refracting telescope is offered on a German equatorial

mount. The CR-150 HD is shipped in two boxes. The first box includes the

optical tube and all of the standard accessories, which include:

• 20mm Plossl Ocular 1-1/4"

• Star Diagonal 1-1/4"

• 2x Barlow Lens 1-1/4", with built-in Camera Adapter

• 9x50mm Finder and Bracket

• Lens Cap with 112mm aperture stop

The second box contains the tripod, equatorial mount and the hardware

needed to set it up. Included are the:

• CG-5 German Equatorial Mount

• Counterweight Bar

• Two 5.1Kg (11 lb.) Counterweights

• Declination (DEC) Slow Motion Knob

• Right Ascension (R.A.) Slow Motion Knob

•AdjustableAluminiumTripod

• Accessory Tray

Unpacking Your

CR-150 HD

Whensettingupthetelescope,findalarge,clearareawherethepartscanbelaidout

withoutfearoflosingthem. Startwiththetripodandmount. Removethecontentsof

theboxandplacethemneatlyonyourworksurface. Leavetheopticaltubeinitsbox

until you are ready to attach it to the mount. Once your CR-150 HD has been

unpacked and assembled, you will not need the shipping boxes for everyday

storage and transportation. However, you should save them in case you decide to

ship your telescope via a common carrier.

The CR-150 HD

•

The CR-150 HD

Figure 2-1

1. Lens Cap (not shown)

2. Dovetail Slidebar

3. Declination Lock

4. Declination Setting Circle

5.CounterweightShaft

6.Counterweights

9. Leg Extension Clamp

10.LatitudeAdjustmentScrew

11. Focus Knobs

12. Eyepiece

13. Finderscope Bracket

14.Finderscope

7. Tripod Leg

8. Accessory Tray

15. Tube Mounting Rings

16.OpticalTube

•

The CR-150 HD

Assembling the CG-5 Equatorial Mount

Setting Up the Tripod

The tripod comes fully assembled with the metal plate, called the tripod head, that

holds the legs together at the top. In addition, the brackets that support the acces-

sorytrayarealsoattachedtothetripod.

Stand the tripod upright and pull the tripod legs apart until the leg brace

assembly for the accessory tray is fully extended (see figure 2-2). The tripod

will now stand by itself. To increase the stability, tighten the bolts that hold

the legs to the tripod head (use the appropriate size wrench from the supplied

set). This will help minimize any flexure or wobble of the legs.

Adjusting the Tripod

Height

Once the tripod is set up, you can adjust the height at which it stands. To do

this:

1. Loosen the knob on the leg clamp so that the tripod leg can be adjusted.

2. Slidethecenterportionofthetripodlegawayfromthetripodheaduntilitis at

thedesiredheight.

3. Tighten the knobs on each leg clamp to hold the legs in place.

Tripod Head

Figure 2-2

Setting up the tripod requires nothing more than pulling the tripod legs away from the

tripod head. The height at which the tripod stands can be adjusted by sliding the slats

in the center of each leg toward or away from the tripod head.

The CR-150 HD

•

Attaching the Accessory

Tray

With the tripod set up, you are ready to attach the accessory tray to the tripod.

There are three wing bolts that hold the accessory tray to the bracket.

1. Locatethethreewingbolts.

2. Place the accessory tray over the bracket and position it so the thread

holes in the accessory tray are above the slotted holes in the bracket.

3. Insert the wing bolts up through the slotted holes in the bracket (see figure

2-3).

4. Thread the wing bolts into the holes in the accessory tray.

5. Tighten the wing bolts fully.

With the accessory tray in place, the tripod will be much more stable making it

easier to attach the mount and telescope.

Figure 2-3

•

The CR-150 HD

Attaching the Equatorial

Mount

Theequatorialmountallowsyoutotiltthetelescope’saxisofrotationsothatyou

cantrackthestarsastheymoveacrossthesky. TheCG-5mountisaGerman

equatorialmountthatattachestothetripodhead(i.e.,metalplateonthetripod). On

onesideoftheplatethereisan“N”whichsignifiesnorth. Thissideofthetripodwill

facenorthwhensettingupforanastronomicalobservingsession. Abovethe“N”is

apegabout3/4"highthatpointsstraightup. Toattachtheequatorialhead:

1. Locate the azimuth adjustment screws on the equatorial mount.

2. Retract the screws so they no longer extend into the azimuth housing

(rectangular extrusion) on the mount. Do NOT remove the screws since

they are needed later for polar alignment.

3. Hold the equatorial mount over the tripod head so that the azimuth housing

is above the metal peg.

4. Place the equatorial mount on the tripod head so that the two are flush.

5. Tighten the knob on the underside of the tripod head to hold the equatorial

mount firmly in place. The knob is already attached and can NOT be

removed.

Figure 2-4

The CR-150 HD

•

AttachingtheR.A. SlowMotionKnob

With the mount securely in place, you are ready to attach some of the accessories

(the telescope tube will be added last). Start with the Right Ascension (R.A.) slow

motionknob. TheR.A.slowmotionknoballowsyoutomakefinepointingadjust-

mentsinthedirectionthetelescopeisaiming(onceitisattachedtothemount). To

installtheknob:

1. Locate the hard plastic shell under the R.A. shafts.

2. Remove either of the two oval tabs by pulling tightly.

3. Line up the flat area on the inner portion of the R.A. slow motion knob with

the flat area on the R.A. shaft.

4. Slide the R.A. slow motion knob onto the R.A. shaft.

The knob is a tension fit, so sliding it on holds it in place. As mentioned

above, there are two R.A. shafts, one on either side of the mount. It makes no

difference which shaft you use since both work the same. Use whichever one

you find more convenient. If, after a few observing sessions, you find the R.A.

slow motion knob is more accessible from the other side, pull firmly to remove

the knob, then install it on the opposite side.

Mounting Platform

Telescope

Mounting Screw

Mounting Platform

Safety Screw

DEC Lock

Lever

DEC Slow Motion

Knob

RA Lock

Lever

Declination Setting

Circle

R.A. Slow Motion

Knob

R.A. Setting

Circle

Polar Housing

Cover

Altitude Adjustment

Control

Azimuth Adjustment

Controls

Figure 2-5

•

The CR-150 HD

AttachingtheDeclinationSlowMotionKnob

LiketheR.A.slowmotionknob,theDECslowmotionknoballowsyoutomakefine

pointingadjustmentsinthedirectionthetelescopeispointed.

TheDECslowmotio