ORION TELESCOPES & BINOCULARS StarBlast AutoTracker 10140, Инструкция по эксплуатации

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to a ratio of 2.5 in brightness. Thus a star of magnitude
1 is 2.5 times brighter than a star of magnitude 2, and
100 times brighter than a magnitude 5 star. The brightest
star, Sirius, has an apparent magnitude of -1.6, the full
moon is -12.7, and the Sun’s brightness, expressed on a
magnitude scale, is -26.78. The zero point of the apparent
magnitude scale is arbitrary.
Meridian: A reference line in the sky that starts at the North
celestial pole and ends at the South celestial pole and
passes through the zenith. If you are facing South, the
meridian starts from your Southern horizon and passes
directly overhead to the North celestial pole.
Messier: A French astronomer in the late 1700’s who was pri-
marily looking for comets. Comets are hazy diffuse objects
and so Messier cataloged objects that were not comets to
help his search. This catalog became the Messier Cata-
log, M1 through M110.
n -
Nebula: Interstellar cloud of gas and dust. Also refers to any
celestial object that has a cloudy appearance.
North Celestial Pole: The point in the Northern hemisphere
around which all the stars appear to rotate. This is caused
by the fact that the Earth is rotating on an axis that pass-
es through the North and South celestial poles. The star
Polaris lies less than a degree from this point and is there-
fore referred to as the “Pole Star”.
Nova: Although Latin for “new” it denotes a star that suddenly
becomes explosively bright at the end of its life cycle.
O -
Open Cluster: One of the groupings of stars that are con-
centrated along the plane of the Milky Way. Most have an
asymmetrical appearance and are loosely assembled.
They contain from a dozen to many hundreds of stars.
P -
Parallax: Parallax is the difference in the apparent position
of an object against a background when viewed by an
observer from two different locations. These positions
and the actual position of the object form a triangle from
which the apex angle (the parallax) and the distance of
the object can be determined if the length of the baseline
between the observing positions is known and the angular
direction of the object from each position at the ends of
the baseline has been measured. The traditional method
in astronomy of determining the distance to a celestial
object is to measure its parallax.
Parfocal: Refers to a group of eyepieces that all require the
same distance from the focal plane of the telescope to be
in focus. This means when you focus one parfocal eye-
piece all the other parfocal eyepieces, in a particular line
of eyepieces, will be in focus.
Parsec: The distance at which a star would show parallax of
one second of arc. It is equal to 3.26 light-years, 206,265
astronomical units, or 30,8000,000,000,000 km. (Apart
from the Sun, no star lies within one parsec of us.)
Point Source: An object which cannot be resolved into an
image because it to too far away or too small is considered
a point source. A planet is far away but it can be resolved
as a disk. Most stars cannot be resolved as disks, they are
too far away.
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 -
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 eclips-
ing 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 coin-
cided 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.