Celestron CR-150 HD instruction manual Nighttime Observing, Telescope Basics •

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Nighttime Observing

Nighttime Observing

Looking at objects in the sky is quite different than looking at objects on Earth. For one, many objects seen in the daytime are easy to see with the naked eye and can be located by using landmarks. In addition, objects on the ground are station- ary, at least for the most part. In the night sky you will see a tremendous amount of stars through the telescope that are not visible to the naked eye. One way to find objects (at least initially) is by using other stars to guide you there. This method of finding objects, known as star hopping, is very accurate. Yet it requires a fair amount of time to learn the stars well enough to guide you to other objects. In addition, the stars will appear to drift out of the field of view. This is due to the Earth’s rotation. In fact, anything in the sky, day or night, will drift out unless the telescope has been polar-aligned and an optional motor drive is running. There is more on this in the section on “Polar Alignment.”

1.Orient the telescope so that the equatorial mount is pointing north, as close to true north as possible. You can use a landmark that you know faces north to get you in the general direction.

2.Adjust the mount until the latitude indicator points to the latitude of your observing site.

3.Insert the eyepiece (low power) into the telescope to give you the widest field possible.

4.You are now ready to observe.

5.Release the right ascension and declination clamps and point the telescope at the desired target. The Moon or one of the brighter planets is an ideal first target.

6.Locate the object in the finder.

7.Lock the R.A. and DEC clamps to hold the telescope in place.

8.Center the object in the finder using the slow motion knobs.

9.Turn the focus knob until the image is sharp.

10.Take your time and study your subject. If looking at the Moon, look for small details in the craters.

That’s all there is to using your Celestron telescope. However, don’t limit your view of an object to a single eyepiece. After a few minutes, try using a different optional eyepiece, a more powerful one. This gives you an idea of how the field of view changes.

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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 Table of Contents Using the Lens Cap Aperture Stop4 Introduction I N T R O D U C T I O NIntroduction How to Use This Manual AWordofCautionThe Mount The Refractor Optical System6 Introduction Unpacking Your CR-150HD A S S E M B L I N G Y O U R C R - 1 5 0 H DThe CR-150HD Assembling the CG-5Equatorial Mount Setting Up the Tripod Adjusting the Tripod HeightTripod Head 10 The CR-150HD Attaching the Accessory TrayAttaching the Equatorial Mount 12 The CR-150HD Attaching the R.A. Slow Motion KnobAttaching the Declination Slow Motion Knob 14 The CR-150HD 1.Lock the DEC clamp to hold the mount in placeTube Rings Dovetail Bracket Attaching the Telescope to the Mount16 The CR-150HD Balancing the Telescope in R.ACOMPLETELY Balancing the Telescope in DECAdjusting the Mount in Azimuth Adjusting the Mount in Altitude18 The CR-150HD Disassembling and Transporting Your CR 150 HD Technical SpecificationsStoring Your CR- 150 HD OPTICAL TUBET E L E S C O P E B A S I C S Attaching the AccessoriesThe Star Diagonal The EyepieceFocuser Tension 1 1/4 AccessoryAdapter Built-inT-AdapterAttaching the Finder Focusing22 Telescope Basics Aligning the Finder YourFirstLook Image OrientationDaytimeObserving 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 Astronomy Basics Motion of the StarsEquator Polar AlignmentDefinition 30 Astronomy BasicsFinding the Pole 32 Astronomy Basics Latitude ScalesPointingatPolaris 34 Astronomy Basics DeclinationDriftPolar Alignment Finders Aligning the R.A Setting CircleObserving the Observing the MoonPlanets C E L E S T I A L O B S E R V I N GObserving the Sun Using the Lens Cap Aperture StopSOLAROBSERVINGHINTS Celestial ObservingObserving Deep-SkyObjects Using the Setting Circles38 Celestial Observing StarHopping 40 Celestial Observing Transparency Viewing ConditionsSky Illumination Seeing42 Celestial Observing Celestial Photography C E L E S T I A L P H O T O G R A P H YLunar Phase Short Exposure Prime FocusCrescent 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 46 Celestial Photography PiggybackEktar 1000 color print Konica 3200 color print 48 Celestial Photography Projection 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 O P T I O N A L A C C E S S O R I E S 50 Optional AccessoriesDual Axis Drive System - #93523 Super Modified Achromatic SMA EyepiecesOptional Accessories Motor Drive System - #93518 52 Optional AccessoriesNGC# THEMESSIERCATALOGConst Type54 The Messier Catalog Const Epoch LIST OF BRIGHT STARSStar Name ConstellationAstronomy Texts FOR FURTHER READINGAtlases General Observational AstronomyCELESTRON ONE YEAR WARRANTY Torrance, CA Tel Fax Celestron International 2835 Columbia StreetItem #21017-INST Price $10.00