Celestron 31058, 31056 instruction manual T I O N a L a C C E S S O R I E S

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O P T I O N A L A C C E S S O R I E S

The following is a partial list of optional accessories available for your Celestron C150-HD and G-8N.

Barlow Lens - A Barlow lens is a negative lens that increases the focal length of a telescope. Used with any eyepiece, it doubles the magnification of that eyepiece. Celestron offers two Barlow lens in the 1-1/4" size for the C150-HD and G-8N. The 2x Ultima Barlow (#93506) is a compact triplet design that is fully multicoated for maximum light transmission and parfocal when used with the Ultima eyepieces. Model #93507 is a compact achromatic Barlow lens that is under three inches long and weighs only 4 oz. It works very well with all Celestron eyepieces.

CD-ROM (93700) - Celestron and Software Bisque have joined together to present this comprehensive CD-ROM called The Sky™ Level 1 - for Celestron. It features a 10,000 object database, 75 color images, horizontal projection, custom sky chart printing, zoom capability, Comet Hale-Bopp coordinates and more! A fun, useful and educational product. PC format.

Dual Axis Drive System - #93523

This drive motor, with drive corrector capabilities, is designed for Celestron’s CG-5 Equatorial telescope mount. It precisely controls the telescope’s tracking speed during long, timed exposures of celestial objects, producing the best possible image sharpness. Drive correctors are a must for those with serious interest in astrophotography or CCD imaging.This precision, state-of- the-art DC motor drive operates on D-Cell batteries. The hand controller module is very compact and fits easily in the palm of your hand. Motors for both axes are included, along with brackets, clutches and hardware.

Eyepieces - Like telescopes, eyepieces come in a variety of designs. Each design has its own advantages and disadvantages. For the 1-1/4" barrel diameter there are four different eyepiece designs available.

• Super Modified Achromatic (SMA) Eyepieces:

The SMA design is an improved version of the Kellner eyepiece. SMAs are very good, economical, general purpose eyepieces that deliver a wide apparent field, good color correction and an excellent image at the center of the field of view. Celestron offers SMA eyepieces in the following focal lengths: 6mm, 10mm, 12mm,17mm and 25mm.

Plössl - Plössl eyepieces have a 4-element lens designed for low-to-high power observing. The Plössls offer razor sharp views across the entire field, even at the edges! In the 1-1/4" barrel diameter, they are available in the following focal lengths: 6.3mm, 7.5mm, 10mm, 12.5mm, 17mm, 20mm, 26mm, 32mm and 40mm.

Ultima - Ultima is not really a design, but a trade name for our 5-element, wide field eyepieces. They are available in the following focal lengths: 5mm, 7.5mm, 12.5mm, 18mm, 24mm, 30mm, 35mm, and 42mm. These eyepieces are all parfocal.

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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 Transparency Viewing ConditionsSky Illumination SeeingCelestial 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