A
million things to look at. Perhaps more. Tiny points of light in the
night sky magically become planets, galaxies and brilliant stars. Quality
optics penetrate the inky blackness of space to reveal its wonders. And
precision adjustment keeps space in the right space. This is the Bushnell®
Astronomical Telescope. Welcome to the universe.
Our NorthStar® telescopes offer
the amateur astronomer state-of-the-art computer-driven location and
tracking capability with simple, push-button control. With a built-in data
base of 20,000 celestial objects, you simply call up your target on the
hand-held control module, enter a simple "go to" command and the Northstar
computer does the rest. Once locked on, tracking the object for prolonged
viewing is automatic. Our new RVO (Real Voice Output) models offer verbal
communications. The remote, hand-held control module features red, backlit
push buttons and a red, illuminated LCD read-out for easy viewing without
impairing your night vision. The telescope also features our new 1x
wide-angle, red dot finderscope. Additional features include a quick-release
tripod and accessory tray for fast, easy assembly.
Please do not throw debris into
the black hole. Actually, the only rule on this guided trip is that you
enjoy the view. The ultimate first telescope, our new Voyager® Sky Tour™
series gives amateur stargazers a pro-grade audio tour of the night sky. Its
Illuminated Smart Mount points the way as the talking handset describes
constellations and planets, and keeps you engaged with entertaining facts
and mythology tidbits. Keeping pace is easy with the LED red dot
finderscope. You’re an instant expert with the Sky Tour series.
The Harbormaster™ Telescope by Bushnell was inspired by a vintage British
import. This refined instrument of fine optical quality and classic
proportions houses modern optical elements with enhanced coatings in solid
brass. Beautiful hand-milled solid wood legs are stained in rich cherry.
Features a coated achromatic air-spaced objective for razor-sharp
resolution. With engraved serial number and certificate of authenticity.
The Harbormaster™ refractor telescope provides a touch of distinction at
a tremendous value. The solid brass tube and vintage cherry-finished base
are classic, yet the modern optics deliver excellent performance.
TELESCOPE TERMINOLOGY
Types of telescopes
Refractor An optical
system that utilizes a series of glass lenses to refract or bend the light
from a distant object such that it can be focused to a point and magnified
by an eyepiece. Popularized by Galileo in the 17th Century, it is
sometimes referred to as a Galilean refractor. Refractors are less
affected by atmospheric instabilities making them perfect for observing
the Moon and planets. Perfect for first-time and novice astronomers, small
refractors are lightweight, portable and require very little maintenance.
And, if you're interested in viewing both land and celestial objects,
refractors are equipped for both uses.
Reflector The optical
system in a reflector uses a primary mirror to reflect the light from a
distant object such that it can be focused to a point and magnified by an
eyepiece. Popularized by Sir Isaac Newton in the 17th Century, it is
sometimes referred to as a Newtonian reflector. Reflectors feature larger
apertures for a wide range of viewing at an affordable price. Designed
with the eyepiece located at the top of the tube, reflectors are more
comfortable to use for viewing night-sky objects such as nebulae, the
Moon, planets and galaxies. Reflectors tend to be heavier and larger than
refractors.
Eyepieces
Lower power eyepieces provide a
wider field of view and a brighter image making them ideal for viewing the
full Moon and planets, star clusters, nebulae and the constellations. To
focus in on the finer details of the Moon and planets such as mountains,
ridges and craters, use an eyepiece with higher magnification.
Barlow Lens
An auxiliary lens that increases
the power by a factor. For example, a 2x barlow doubles the magnification of
the telescope.
Erecting Lens
Lens used with a refractor
telescope when viewing land-based objects to correct the normally upside
down image provided by an astronomical telescope.
Finderscope
On most astronomical telescopes a
lower powered finderscope with a wider field of view lets the user quickly
locate the object to be viewed by the high-magnification main telescope.
There are two types of finderscopes, optical and red dot.
Focal Length
The measured light path of the
optical system (tube length), typically measured in millimeters.
Focusing knob
Controls the rack and pinion
focusing system. Permits smooth movement of eyepiece for precise, sharp
images.
Magnification (Power)
Telescopes are often referred to
by two numbers separated by an "x". For example: 100x4.5". The first number
is the power or magnification of the telescope. With a 100x4.5" telescope,
the object being viewed appears to be 100 times closer than you would see it
with the unaided eye.
The magnification of a telescope
is determined by dividing its focal length by the focal length of the
eyepiece being used. For example, a 500mm telescope with a 5mm eyepiece
would magnify objects 100x. Thus, a telescope can provide nearly any
magnification required depending on the focal length of the eyepiece used.
Since most objects in the sky are
rather large, high magnification isn't necessary. Rather, a telescope that
gathers lots of light is needed to make dim objects appear brighter and
sharper. The power or magnification contributes to the overall size and bulk
of the telescope. This is because as the power increases, so must the
physical size of the objective lens.
Objective Lens Size (or
Aperture)
The second number in the formula
(100x4.5") is the diameter of the objective lens or mirror. The aperture
relates directly to how bright images will appear and how much detail is
revealed. The larger the objective lens, the better.
The size of the telescope's
objective lens, or aperture, limits the amount of power that can be used
effectively. As the magnification of an object increases, the brightness of
the image decreases. This is because the light gathered by the telescope is
being spread over a larger area.
Aperture also limits the clarity
of an image at increased magnification. When magnified beyond an aperture's
recommended power, the image dims and becomes fuzzy.
Penta Mirror Technology
This patented Bushnell technology
breakthrough allows for left-to-right correct view of the stars (not
backwards-as in most telescope models) taking the guesswork out of where to
move the telescope. This feature provides unparalleled ease of use for
finding and tracking objects with a 90 degree viewing angle and 1.25"
eyepiece adapter.
Resolution
Resolution, or definition, is the
ability of a telescope to distinguish fine detail and retain clarity.
Rotary Power Turret
This patented Bushnell feature
allows for magnification and accessory changes to occur through a simple
twist of the turret or accessory dial. Accessories are incorporated into the
telescope so there are no loose parts, and magnification and accessory
changes can be made instantaneously to suit viewing conditions.
Types of telescope mounts
The mount secures the telescope
to the tripod. It allows you to move your telescope horizontally and
vertically. There are two primary types of telescope mounts,
altitude-azimuth (or altaz) and equatorial. Altaz mounts move up-down and
left-right. Equatorial mounts are tilted to align with the rotational
(polar) axis of the Earth.
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© 2002-2010