Celestron Advanced Series GT, C6-RGT 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 Assembly Version Get Alt-Az Goto Alt-Az Hibernate Turn On/Off GPS Page Advanced Series C6-R C8-N ShownAdvanced Series C6-RGT 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 Installing the Finderscope Balancing the Tube in R.A Telescope Tube CompletelyAdjusting the Mount Adjusting the Mount in AltitudeAttaching the Declination Cable For GT Models Only Adjusting the Mount in AzimuthPowering the Telescope Advanced GT Hand Control Hand Control Operation Double StarsAlignment Procedures Startup ProcedureAuto Align Auto Three-Star AlignRe-Alignment Quick-AlignLast Alignment Object Catalog Selecting an ObjectSlewing to an Object Finding PlanetsTour Mode Constellation TourDirection Buttons Rate ButtonSetup Procedures Identify Scope Setup Features Precise GoToObserving 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 Pointing at Polaris Finding 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 TransparencyUsing the Lens Cap Aperture Stop Piggyback Short Exposure Prime Focus Photography Reducing Vibration Terrestrial PhotographyMetering Auto Guiding Care and Cleaning of the Optics CollimationCollimated telescope Should appear as a 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 Appendix E Maps of Time Zones Page Page Page Page Page Page Page Celestron TWO Year Warranty
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Advanced Series GT, C6-R, C6-RGT specifications

The Celestron C6-RGT and C6-R models, part of the Advanced Series GT lineup, are popular choices for amateur astronomers seeking high-quality optics and reliable features. The C6-RGT, equipped with a 6-inch refractor, is designed for both visual and astrophotographic pursuits. Its impressive features make it a great option for anyone looking to explore the night sky in greater detail.

One of the standout characteristics of the C6-RGT is its large 6-inch aperture, which allows for exceptional light-gathering capability. This feature is crucial for viewing faint celestial objects, giving users the ability to observe details in nebulae, galaxies, and star clusters. The refractor design minimizes chromatic aberration, ensuring sharp and clear images across a wide range of viewing conditions.

The telescope comes with a fully multi-coated optics system that enhances light transmission and contrast, creating brighter and clearer images. The C6-R is also designed with a robust aluminum tube that not only ensures durability but also helps maintain stability during long observing sessions.

The Advanced Series GT mount is another essential element of the C6-RGT and C6-R models. This computerized mount features a sturdy, stable design that supports a wide range of telescopes while providing smooth tracking of celestial objects. The GoTo technology allows users to locate and track over 40,000 celestial objects with ease. This high level of automation is particularly helpful for beginners who may be unfamiliar with the night sky.

Another notable feature of the Advanced Series GT is its ability to be controlled through a smartphone or tablet, thanks to Celestron's SkyPortal app. This integration opens doors for enhanced stargazing experiences, offering customizable tours and educational information right at your fingertips.

In terms of usability, both models have a comfortable height and the mount can be easily adjusted to accommodate various observing positions. The telescope is also portable, making it convenient for outreach events or trips to dark-sky locations.

Overall, the Celestron C6-RGT and C6-R models, with their combination of powerful optics, advanced technology, and user-friendly features, represent an excellent choice for both budding astronomers and passionate enthusiasts. With Celestron’s commitment to quality and innovation, these telescopes promise to deliver unforgettable views of the wonders of the universe.
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