Celestron 31058, 31056 instruction manual Removing the Lens Cap, Balancing the Telescope in R.A

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Removing the Lens Cap

The G-8N lens cover has a 1-1/2" cap covering an aperture stop that is offset from the center. To utilize the aperture stop, leave the telescope cover on the front of the tube and remove only the small aperture stop cap from the front of the cover. This is useful when observing very bright objects, like the full moon. The aperture stop reduces the amount of light entering the tube resulting in better resolution. Do not

use the aperture stop to view the Sun unless using a proper solar filter.

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 mounting bracket screw is tight). The counter- weight 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 the counterweight.

4.Move the counterweight to a point where it balances 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 astrophotographs, 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., finderscope, eyepiece, etc.) have been attached to the telescope. The correct procedure for attaching these accessories is discussed latr in this section.

The G-8N • 19

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Contents C150-HD and G-8N Newtonian Page B L E N T E N T S Celestial Photography T R O D U C T I O N How to Use this Manual Word of Caution Newtonian Optical System Unpacking Your G-8N S E M B L I N G Y O U R N E W T O N I a N T E L E S C O P EG-8N C150-HD Adjusting the Tripod Height Setting Up the TripodAttaching the Accessory Tray They are needed later for polar alignment Attaching the Equatorial MountAttaching the R.A. Slow Motion Knob Attaching the Declination Slow Motion Knob Attaching the Counterweight Bar and Counterweight Attaching the Telescope to the Mount For G-8N Attaching the Telescope to the Mount For C150- HD Balancing the Telescope in R.A Removing the Lens CapCompletely Balancing the Telescope in DECG-8N C150-HD Installing the Finderscope Installing the Eye- piece Technical Specifications ActualVeiw NewtonianView Image OrientationFocusing Aligning the Finder Daytime Observing Your First LookNighttime Observing Calculating Magnification Determining Field of View Celestial Coordi- nate System T R O N O M Y B a S I C SMotion of the Stars Definition Polar AlignmentFinding the Pole Latitude Scales Pointing at Polaris Declination Drift Polar Alignment Finders Aligning the R.A Setting CircleObserving the Moon Planets L E S T I a L O B S E R V I N GObserving Deep-Sky Objects Observing the S u nUsing the Setting Circles Star Hopping Celestial Observing Seeing Viewing ConditionsTransparency Sky IlluminationCelestial Observing L E S T I a L P H O T O G R a P H Y Short Exposure Prime F o c u s Lunar Phase ISO Crescent Quarter 125 Full 250Piggyback Celestial Photography L E S C O P E M a I N T E N a N C E Care and Cleaning of the Optics CollimationOr back out the holder screws more than one 1 to two 2 turns T I O N a L a C C E S S O R I E S Optional Accessories Single Axis Motor Drive System #93518 Themessiercatalog Great Orion Nebula Elliptical Galaxy List of Bright Stars For Further Reading Celestron ONE Year Warranty