Celestron C80ED-R, C100ED-R manual Appendix B Glossary of Terms

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Appendix B - Glossary of Terms

A-

Absolute magnitude

The apparent magnitude that a star would have if it were observed from a standard distance of 10

 

parsecs, or 32.6 light-years. The absolute magnitude of the Sun is 4.8. at a distance of 10 parsecs, it

 

would just be visible on Earth on a clear moonless night away from surface light.

Airy disk

The apparent size of a star's disk produced even by a perfect optical system. Since the star can never

 

be focused perfectly, 84 per cent of the light will concentrate into a single disk, and 16 per cent into

 

a system of surrounding rings.

Alt-Azimuth Mounting

A telescope mounting using two independent rotation axis allowing movement of the instrument in

 

Altitude and Azimuth.

Altitude

In astronomy, the altitude of a celestial object is its Angular Distance above or below the celestial

 

horizon.

Aperture

the diameter of a telescope's primary lens or mirror; the larger the aperture, the greater the

 

telescope's light-gathering power.

Apparent Magnitude

A measure of the relative brightness of a star or other celestial object as perceived by an observer on

 

Earth.

Arcminute

A unit of angular size equal to 1/60 of a degree.

Arcsecond

A unit of angular size equal to 1/3,600 of a degree (or 1/60 of an arcminute).

Asterism

A small unofficial grouping of stars in the night sky.

Asteroid

A small, rocky body that orbits a star.

Astrology

The pseudoscientific belief that the positions of stars and planets exert an influence on human

 

affairs; astrology has nothing in common with astronomy.

Astronomical unit (AU)

The distance between the Earth and the Sun. It is equal to 149,597,900 km., usually rounded off to

Aurora

150,000,000 km.

The emission of light when charged particles from the solar wind slams into and excites atoms and

 

molecules in a planet's upper atmosphere.

Azimuth

The angular distance of an object eastwards along the horizon, measured from due north, between

 

the astronomical meridian (the vertical line passing through the center of the sky and the north and

 

south points on the horizon) and the vertical line containing the celestial body whose position is to

B -

be measured. .

 

Binary Stars

Binary (Double) stars are pairs of stars that, because of their mutual gravitational attraction, orbit

 

around a common Center of Mass. If a group of three or more stars revolve around one another, it

 

is called a multiple system. It is believed that approximately 50 percent of all stars belong to binary

 

or multiple systems. Systems with individual components that can be seen separately by a telescope

 

are called visual binaries or visual multiples. The nearest "star" to our solar system, Alpha Centauri,

 

is actually our nearest example of a multiple star system, it consists of three stars, two very similar

C -

to our Sun and one dim, small, red star orbiting around one another.

 

Celestial Equator

The projection of the Earth's equator on to the celestial sphere. It divides the sky into two equal

Celestial pole

hemispheres.

The imaginary projection of Earth's rotational axis north or south pole onto the celestial sphere.

Celestial Sphere

An imaginary sphere surrounding the Earth, concentric with the Earth's center.

Collimation

The act of putting a telescope's optics into perfect alignment.

D -

 

Declination (DEC)

The angular distance of a celestial body north or south of the celestial equator. It may be said to

E -

correspond to latitude on the surface of the Earth.

 

Ecliptic

The projection of the Earth's orbit on to the celestial sphere. It may also be defined as "the apparent

 

yearly path of the Sun against the stars".

Equatorial mount

A telescope mounting in which the instrument is set upon an axis which is parallel to the axis of the

 

Earth; the angle of the axis must be equal to the observer's latitude.

F -

 

Focal length

The distance between a lens (or mirror) and the point at which the image of an object at infinity is

 

brought to focus. The focal length divided by the aperture of the mirror or lens is termed the focal

 

ratio.

 

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Contents Advanced Series Advanced Series GT Introduction Care and Cleaning of the Optics Page Advanced GT Series 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 OnlyFor Non-GT Models Only Attaching the Telescope Tube to the Mount Installing the Finderscope Optical TubeInstalling the Eyepieces Balancing the Tube in R.AAdjusting the Mount Balancing the Telescope in DECAdjusting the Mount in Altitude Adjusting the Mount in AzimuthAttaching the Declination Cable For GT Models Only Powering the Telescope Advanced GT Hand Control Hand Control Operation Double StarsAlignment Procedures Startup ProcedureAuto Align Auto Three-Star AlignQuick-Align Last AlignmentRe-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 Focusing Aligning the FinderscopeCalculating Magnification Determining Field of View General Observing HintsCelestial Coordinate System Motion of the Stars Pointing at Polaris Finding the North Celestial Pole DefinitionDeclination 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 Terrestrial Photography MeteringReducing Vibration Auto Guiding Care and Cleaning of the Optics 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

C100ED-R, C80ED-R specifications

Celestron, a renowned name in the field of astronomy, has built a reputation for producing high-quality telescopes that are accessible to both amateur and professional astronomers alike. Among their impressive lineup are the Celestron C100ED-R and C80ED-R telescopes, both of which are crafted to enhance the observational experience through advanced optics and user-friendly features.

The Celestron C100ED-R, a 100mm refractor telescope, stands out for its premium extra-low dispersion (ED) glass, which delivers exceptional color correction and sharpness. This ED technology minimizes chromatic aberration, ensuring clearer and more colorful celestial images. The telescope boasts a focal length of 900mm, resulting in a focal ratio of f/9. This combination allows for high magnification capabilities while maintaining a wide field of view, perfect for observing both planetary details and deep-sky objects. The robust, yet lightweight design of the C100ED-R makes it highly portable, allowing for convenient stargazing sessions.

On the other hand, the C80ED-R is a 80mm refractor telescope that combines portability with performance. With its 600mm focal length and f/7.5 focal ratio, the C80ED-R is ideal for wide-field observations, making it easy to explore star clusters and large nebulae. Like its larger counterpart, the C80ED-R features ED glass, which prevents color distortion, allowing for clear and crisp images. The compact design is perfect for those who wish to travel or set up in tight spaces, ensuring that astronomy remains accessible.

Both telescopes are equipped with high-quality multi-coated optics that enhance light transmission, resulting in brighter images. Celestron's user-friendly mounting systems allow for smooth tracking of celestial objects, making it easier to follow objects as they move across the night sky. Additionally, these telescopes come with a variety of accessories, including premium eyepieces that enhance the viewing experience, and sturdy tripods that provide stable support during observations.

In summary, both the Celestron C100ED-R and C80ED-R offer exceptional features that cater to a variety of observing needs. With advanced ED optics, high-quality construction, and portability, they are ideal choices for aspiring astronomers looking to explore the wonders of the universe. Whether you're interested in planetary observation or deep-sky exploration, Celestron's C100ED-R and C80ED-R will not disappoint.