Celestron CR-150 HD instruction manual Balancing the Telescope in R.A, The CR-150HD

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Balancing the Telescope in R.A.

Balancing the Telescope in R.A.

To eliminate undue stress on the mount, the telescope should be properly balanced around the polar axis. In addition, proper balancing is crucial for accurate tracking if using an optional motor drive. To balance the mount:

1.Release the R.A. Clamp and position the telescope off to one side of the mount (make sure that the balance bracket thumbscrew is tight). The counterweight bar will extend horizontally on the opposite side of the mount (see figure 2-9).

2.Release the telescope — GRADUALLY — to see which way the telescope “rolls.”

3.Loosen the set screw on one or both counterweights.

4.Move the counterweights to a point where they balance the telescope (i.e., it remains stationary when the R.A. clamp is released).

5.Tighten the set screw to hold the counterweight(s) in place.

These are general balance instructions and will reduce undue stress on the mount. When taking astrophotos, this balance process should be done for the specific area at which the telescope is pointing.

Figure 2-9

The telescope should be balanced after all the standard accessories (i.e., star diagonal, eyepiece, etc.) have been attached to the telescope. The correct procedure for attaching these accessories is discussed in the section on “Telescope Basics.”

16 • The CR-150 HD

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Contents The CR-150HD Model #210176 Refractor ii Table of Contents T A B L E O F C O N T E N T SAssembling the CG-5Equatorial Mount Using the Lens Cap Aperture Stop Table of ContentsI N T R O D U C T I O N 4 IntroductionHow to Use This Manual AWordofCaution IntroductionThe Mount The Refractor Optical System6 Introduction A S S E M B L I N G Y O U R C R - 1 5 0 H D Unpacking Your CR-150HDThe CR-150HD Assembling the CG-5Equatorial Mount Setting Up the Tripod Adjusting the Tripod HeightTripod Head Attaching the Accessory Tray 10 The CR-150HDAttaching the Equatorial Mount Attaching the R.A. Slow Motion Knob 12 The CR-150HDAttaching the Declination Slow Motion Knob 1.Lock the DEC clamp to hold the mount in place 14 The CR-150HDAttaching the Telescope to the Mount Tube Rings Dovetail BracketBalancing the Telescope in R.A 16 The CR-150HDBalancing the Telescope in DEC COMPLETELYAdjusting the Mount in Azimuth Adjusting the Mount in Altitude18 The CR-150HD Technical Specifications Disassembling and Transporting Your CR 150 HDStoring Your CR- 150 HD OPTICAL TUBEAttaching the Accessories T E L E S C O P E B A S I C SThe Star Diagonal The Eyepiece1 1/4 Accessory Focuser TensionAdapter Built-inT-AdapterAttaching the Finder Focusing22 Telescope Basics Aligning the Finder Image Orientation YourFirstLookDaytimeObserving NEVER POINT YOUR TELESCOPE AT THE SUN UNLESSNighttime Observing Determining Field of View Calculating Magnification26 Telescope Basics GeneralPhotographyHints Your Celestron telescope can be used for both terrestrial and astronomical photography. Your telescope has a fixed aperture and, as a result, a fixed f/ratio. To properly expose your subjects photographically, you need to set your shutter speed accordingly. Most 35mm single lens reflex SLR cameras offer through-the-lens metering that lets you know if your picture is under or overexposed. This is important for terrestrial photography where exposure times are measured in fractions of a second. In astrophotography, the exposures are much longer, requiring that you use the “B” setting on your camera. The actual exposure time is determined by how long you keep the shutter open. More on this in the section on “Celestial Photography.” The Celestial Coordi- nate System A S T R O N O M Y B A S I C S28 Astronomy Basics Motion of the Stars Astronomy BasicsPolar Alignment EquatorDefinition 30 Astronomy BasicsFinding the Pole Latitude Scales 32 Astronomy BasicsPointingatPolaris DeclinationDrift 34 Astronomy BasicsAligning the R.A Setting Circle Polar Alignment FindersObserving the Moon Observing thePlanets C E L E S T I A L O B S E R V I N GUsing the Lens Cap Aperture Stop Observing the SunSOLAROBSERVINGHINTS Celestial ObservingObserving Deep-SkyObjects Using the Setting Circles38 Celestial Observing StarHopping 40 Celestial Observing Viewing Conditions TransparencySky Illumination Seeing42 Celestial Observing C E L E S T I A L P H O T O G R A P H Y Celestial PhotographyShort Exposure Prime Focus Lunar PhaseCrescent QuarterThe exposure times listed here should be used as a starting point. Always make exposures that are longer and shorter than the recommended time. Also, try bracketing your exposures, taking a few photos at each shutter speed. This will ensure that you will get a good photo. If using black and white film, try a yellow filter to reduce the light intensity and to increase contrast Piggyback 46 Celestial PhotographyEktar 1000 color print Konica 3200 color print Projection Photography 48 Celestial PhotographyT E L E S C O P E M A I N T E N A N C E Care and Cleaning of the OpticsTelescope Maintenance 50 Optional Accessories O P T I O N A L A C C E S S O R I E SDual Axis Drive System - #93523 Super Modified Achromatic SMA EyepiecesOptional Accessories 52 Optional Accessories Motor Drive System - #93518THEMESSIERCATALOG NGC#Const Type54 The Messier Catalog NGC# LIST OF BRIGHT STARS EpochStar Name ConstellationFOR FURTHER READING Astronomy TextsAtlases General Observational AstronomyCELESTRON ONE YEAR WARRANTY Torrance, CA Tel Fax Celestron International 2835 Columbia StreetItem #21017-INST Price $10.00