Celestron OMNI XLT 102 manual

Page 54

R -

 

Reflector

A telescope in which the light is collected by means of a mirror.

Resolution

The minimum detectable angle an optical system can detect. Because of diffraction, there is a limit

 

to the minimum angle, resolution. The larger the aperture, the better the resolution.

Right Ascension: (RA)

The angular distance of a celestial object measured in hours, minutes, and seconds along the

 

Celestial Equator eastward from the Vernal Equinox.

S -

 

Schmidt Telescope

Rated the most important advance in optics in 200 years, the Schmidt telescope combines the best

 

features of the refractor and reflector for photographic purposes. It was invented in 1930 by

 

Bernhard Voldemar Schmidt (1879-1935).

Sidereal Rate

This is the angular speed at which the Earth is rotating. Telescope tracking motors drive the

 

telescope at this rate. The rate is 15 arc seconds per second or 15 degrees per hour.

T -

 

Terminator

The boundary line between the light and dark portion of the moon or a planet.

U -

 

Universe

The totality of astronomical things, events, relations and energies capable of being described

 

objectively.

V -

 

Variable Star

A star whose brightness varies over time due to either inherent properties of the star or something

 

eclipsing or obscuring the brightness of the star.

W -

 

Waning Moon

The period of the moon's cycle between full and new, when its illuminated portion is decreasing.

Waxing Moon

The period of the moon's cycle between new and full, when its illuminated portion is increasing.

Z -

 

 

 

Zenith

The point on the Celestial Sphere directly above the observer.

Zodiac

The zodiac is the portion of the Celestial Sphere that lies within 8 degrees on either side of the

 

Ecliptic. The apparent paths of the Sun, the Moon, and the planets, with the exception of some

 

portions of the path of Pluto, lie within this band. Twelve divisions, or signs, each 30 degrees in

 

width, comprise the zodiac. These signs coincided with the zodiacal constellations about 2,000 years

 

ago. Because of the Precession of the Earth's axis, the Vernal Equinox has moved westward by

 

about 30 degrees since that time; the signs have moved with it and thus no longer coincide with the

 

constellations.

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Contents Omni XLT Series Telescopes Table of Contents Astrophotography Page Omni XLT 102 Refractor Omni XLT 150 Newtonian Omni XLT 127 Schmidt-Cassegrain Setting up the Tripod Attaching the Equatorial Mount Installing the Counterweight Bar Attaching the Center Leg BraceInstalling the Counterweights Attaching the Slow Motion Control Knobs CablesAttaching the Telescope Tube to the Mount Installing the Finderscope Installing the Visual BackInstalling the Star Diagonal Installing the EyepiecesMoving the Telescope Manually Balancing the Mount in R.AAdjusting the Mount Balancing the Mount in DECAdjusting the Mount in Altitude Adjusting the Mount in AzimuthPage Page Focusing Image OrientationAligning the Finderscope Calculating MagnificationDetermining Field of View General Observing HintsCelestial Coordinate System Motion of the Stars Latitude Scale Pointing at PolarisFinding the North Celestial Pole Polar Alignment in the Southern Hemisphere Polar Alignment with the Latitude ScalePointing at Sigma Octantis Finding the South Celestial Pole SCPDeclination Drift Method of Polar Alignment Aligning the R.A. Setting Circle Using the R.A. Vernier Scale 11 Vernier ScaleObserving the Planets Observing the MoonLunar Observing Hints Planetary Observing HintsObserving Deep Sky Objects Observing the SunSolar Observing Hints Seeing ConditionsUsing the Lens Cap Aperture Stop with Refractor Telescopes SeeingPiggyback Photography Using Digital Cameras Eyepiece Projection for a Schmidt-Cassegrain FullLong Exposure Prime Focus Photography Planetary and Lunar Photography with Special Imagers Metering CCD Imaging for Deep Sky ObjectsTerrestrial Photography Reducing VibrationCare and Cleaning of the Optics Collimation of RefractorsCollimation of a Schmidt-Cassegrain Two 2 turnsCollimated telescope Should appear Symmetrical with Collimation of a Newtonian Aligning the Secondary MirrorBoth mirrors aligned with your eye looking into the focuser Night Time Star Collimating As a Series 1 # Page Page Appendix a Technical Specifications Appendix B Glossary of Terms Page Page Page Page Page Page Page Page Celestron Two Year Warranty
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