Celestron CR-150 HD instruction manual Aligning the Finder, Telescope Basics

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Aligning the Finder

Figure 4-2

The finder comes mounted in the finder bracket. To mount the finder to the telescope, the finder bracket attaches to the mounting bracket on the telescope.

Aligning the Finder

The CR-150 HD comes with a 9x50mm finder. The finder is designed to help you find objects that are easily overlooked in the main optics of the telescope. The first number used to describe the finder is the power. The second number is the diameter of the objective lens in millimeters. For example, the CR-150 HD finder is 9x50 which means it is 9 power and has a 50mm objective lens. Incidentally, power is always compared to the unaided human eye. So, a 9 power finder magnifies images nine times more than the human eye.

The 9x50mm finder is adjusted using two adjustment screws, located on the top and on the right (when looking though the finder) of the finder bracket and a spring loaded pivot screw (located on the left side of the bracket). This allows you to turn the top adjustment screw to move the finderscope up and down, and turn the right adjustment screw to move the finderscope right to left. The spring loaded pivot screw puts constant pressure on the finder so that the adjustment screws are always makingcontactwiththefinder.

To make things a little easier, you should align the finder during the day when it is easier to locate objects. To align the finder:

1.Choose a conspicuous object that is over 500 yards away. This will eliminate any possible parallax effect.

2.Point your telescope at the target and center it in the main optics of the telescope (the eyepiece).

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

4.Check the finder to see where the object is located in the field of view.

5.Adjust the screws on the finder bracket, tightening one while loosening another, until the cross hairs are centered on the target.

Accurate alignment of the finder will make it much easier to find objects in the main opticaltube.

Telescope Basics • 23

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Contents 6 Refractor Model #21017The CR-150HD Assembling the CG-5Equatorial Mount T A B L E O F C O N T E N T Sii Table of Contents 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 AWordofCaution6 Introduction The Refractor Optical SystemThe Mount 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 Tripod Head Setting Up the Tripod Adjusting the Tripod HeightAssembling the CG-5Equatorial Mount 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 DEC18 The CR-150HD Adjusting the Mount in AltitudeAdjusting the Mount in Azimuth OPTICAL TUBE Technical SpecificationsDisassembling and Transporting Your CR 150 HD Storing Your CR- 150 HDThe Eyepiece Attaching the AccessoriesT E L E S C O P E B A S I C S The Star DiagonalBuilt-inT-Adapter 1 1/4 AccessoryFocuser Tension Adapter22 Telescope Basics FocusingAttaching the Finder Aligning the Finder NEVER POINT YOUR TELESCOPE AT THE SUN UNLESS Image OrientationYourFirstLook DaytimeObservingNighttime Observing 26 Telescope Basics Calculating MagnificationDetermining Field of View 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.” 28 Astronomy Basics A S T R O N O M Y B A S I C SThe Celestial Coordi- nate System Astronomy Basics Motion of the Stars30 Astronomy Basics Polar AlignmentEquator DefinitionFinding the Pole 32 Astronomy Basics Latitude ScalesPointingatPolaris 34 Astronomy Basics DeclinationDriftPolar Alignment Finders Aligning the R.A Setting CircleC E L E S T I A L O B S E R V I N G Observing the MoonObserving the PlanetsCelestial Observing Using the Lens Cap Aperture StopObserving the Sun SOLAROBSERVINGHINTS38 Celestial Observing Using the Setting CirclesObserving Deep-SkyObjects StarHopping 40 Celestial Observing Seeing Viewing ConditionsTransparency Sky Illumination42 Celestial Observing Celestial Photography C E L E S T I A L P H O T O G R A P H YQuarter Short Exposure Prime FocusLunar Phase CrescentThe 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 PhotographyTelescope Maintenance Care and Cleaning of the OpticsT E L E S C O P E M A I N T E N A N C E Super Modified Achromatic SMA Eyepieces 50 Optional AccessoriesO P T I O N A L A C C E S S O R I E S Dual Axis Drive System - #93523Optional Accessories Motor Drive System - #93518 52 Optional AccessoriesType THEMESSIERCATALOGNGC# Const54 The Messier Catalog Proper Name Constellation LIST OF BRIGHT STARSEpoch Star NameGeneral Observational Astronomy FOR FURTHER READINGAstronomy Texts AtlasesCELESTRON ONE YEAR WARRANTY Item #21017-INST Price $10.00 Celestron International 2835 Columbia StreetTorrance, CA Tel Fax