Celestron C10-N, C8-NGT manual Celestial Coordinate System

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Up to this point, this manual covered the assembly and basic operation of your telescope. However, to understand your telescope more thoroughly, you need to know a little about the night sky. This section deals with observational astronomy in general and includes information on the night sky and polar alignment.

The Celestial Coordinate System

To help find objects in the sky, astronomers use a celestial coordinate system that is similar to our geographical coordinate system here on Earth. The celestial coordinate system has poles, lines of longitude and latitude, and an equator. For the most part, these remain fixed against the background stars.

The celestial equator runs 360 degrees around the Earth and separates the northern celestial hemisphere from the southern. Like the Earth's equator, it bears a reading of zero degrees. On Earth this would be latitude. However, in the sky this is referred to as declination, or DEC for short. Lines of declination are named for their angular distance above and below the celestial equator. The lines are broken down into degrees, minutes of arc, and seconds of arc. Declination readings south of the equator carry a minus sign (-) in front of the coordinate and those north of the celestial equator are either blank (i.e., no designation) or preceded by a plus sign (+).

The celestial equivalent of longitude is called Right Ascension, or R.A. for short. Like the Earth's lines of longitude, they run from pole to pole and are evenly spaced 15 degrees apart. Although the longitude lines are separated by an angular distance, they are also a measure of time. Each line of longitude is one hour apart from the next. Since the Earth rotates once every 24 hours, there are 24 lines total. As a result, the R.A. coordinates are marked off in units of time. It begins with an arbitrary point in the constellation of Pisces designated as 0 hours, 0 minutes, 0 seconds. All other points are designated by how far (i.e., how long) they lag behind this coordinate after it passes overhead moving toward the west.

Figure 5-1

The celestial sphere seen from the outside showing R.A. and DEC.

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Contents Advanced Series Advanced Series GT Precise GoTo Scope Setup Features Telescope Maintenance Page Advanced Series Newtonian Advanced Series GT Newtonian Setting up the Tripod Attaching the Equatorial MountInstalling the Counterweight Bar Attaching the Center Leg BraceInstalling the Counterweight Attaching the Hand Control Holder Advanced GT Models OnlyAttaching the Telescope Tube to the Mount Telescope Installing the FinderscopeInstalling the Eyepieces Balancing the Tube in R.A Telescope Tube CompletelyAdjusting the Mount Adjusting the Mount in AltitudePowering the Telescope Attaching the Declination Cable For GT Models OnlyAdvanced GT Hand Control Hand Control Operation Alignment Procedures Startup ProcedureAuto Align Auto Three-Star AlignRe-Alignment Quick-AlignLast Alignment Object Catalog Selecting an ObjectTour Mode Setup Procedures Nine available slew speedsIdentify Scope Setup Features Observing Tip Helpful Hint Utility Features Helpful Hint Advanced GT Image Orientation Calculating Magnification FocusingAligning the Finderscope Determining Field of View General Observing HintsCelestial Coordinate System Motion of the Stars Latitude Scales Pointing at PolarisFinding the North Celestial Pole Declination Drift Method of Polar Alignment Observing the Moon Lunar Observing HintsObserving the Planets Observing the SunSolar Observing Hints Observing Deep Sky ObjectsSeeing Conditions TransparencyPage Piggyback Short Exposure Prime Focus Photography Reducing Vibration Terrestrial PhotographyMetering Auto Guiding Aligning the Secondary Mirror Care and Cleaning of the OpticsCollimation Aligning the Primary Mirror Night Time Star Collimating Page Page Page Page Appendix a Technical Specifications Appendix B Glossary of Terms Page Eclipsing or obscuring the brightness of the star Appendix C Longitudes Latitudes Georgia Minnesota Rhode Island Canada Appendix D RS-232 Connection Additional RS232 Commands Reset The Position Of Azm Or AltAppendix E Maps of Time Zones Page Page Page Page Page Page Page Celestron TWO Year Warranty
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C10-N, C8-NGT, C8-N specifications

The Celestron C8-NGT, C8-N, and C10-N telescopes represent a range of superior astronomical instruments that cater to both novice and experienced astronomers alike. Among these, the C8-NGT combines the advanced features of a computerized telescope with the simplicity of a Newtonian design. Its 8-inch aperture allows for impressive light-gathering capability, making it ideal for observing distant galaxies, star clusters, and nebulae. The GoTo mount enhances usability, enabling users to locate celestial objects effortlessly with the push of a button.

The C8-N, also featuring an 8-inch aperture, stands out with its open tube design that provides maximum airflow and minimizes thermal issues, ensuring optimal performance. The scope is designed with user-friendly adjustments and a sturdy equatorial mount, allowing for smooth tracking of celestial objects. Its high-quality optics provide sharp images and incredible clarity, making it suitable for both planetary and deep-sky observations.

On the other hand, the C10-N is the largest in this lineup, boasting a 10-inch aperture that dramatically enhances its light-gathering ability. This larger size makes the C10-N a powerhouse for serious astronomers looking to explore fainter objects and intricate details within astronomical features. Like the C8-N, it employs a Newtonian reflector design, allowing for a compact and manageable profile, while still providing stunning visuals across a range of celestial bodies.

All three telescopes incorporate Celestron's commitment to creating durable, robust, and user-friendly systems. They utilize premium quality glass and optics, which are coated to improve light transmission and provide high-contrast images. Additionally, they are designed with ease of assembly and portability in mind, catering to astronomers who enjoy observing in various locations.

The Celestron C8-NGT, C8-N, and C10-N serve as excellent options for anyone looking to deepen their astronomical pursuits, offering a blend of advanced technology, high-quality optical performance, and user-friendly features. Whether you're a beginner eager to peer into the wonders of the universe or an experienced observer at the peak of your skills, these telescopes offer a remarkable means to expand your cosmic horizons. With precision engineering and thoughtful design, Celestron continues to be a trusted name in the world of astronomy.
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