Orion CT80 User Manual

13
To nd deep-sky objects with your telescope, you rst need
to become reasonably familiar with the night sky. Unless you
know how to recognize the constellation Orion, for instance,
you won’t have much luck locating the Orion Nebula. A simple
planisphere, or star wheel, can be a valuable tool for learning
the constellations and seeing which ones are visible in the
sky on a given night. Once you have identied a few constel-
lations, a good star chart, atlas, or astronomy app will come in
handy for helping locate interesting deep-sky objects to view
within the constellations.
Do not expect these objects to appear like the photographs
you see in books and on the internet; most will look like dim
gray smudges. Our eyes are not sensitive enough to see color
in deep-sky objects except in a few of the brightest ones. But
as you become more experienced and your observing skills
get sharper, you will be able to ferret out more and more sub-
tle details and structure.
6. Worthwhile Optional
Accessories
• Moon Filter – A 1.25" Moon lter will cut down the strong
glare of sunlight reected from the Moon, making Moon
viewing more comfortable and revealing more surface
detail. The lter threads into the bottom of the Kellner eye-
pieces that came with your telescope.
• Motor Drive – A motor drive, which attaches to the right
ascension axis of an equatorial telescope mount, enables
your telescope to “track” the motion of stars and other
celestial objects as they drift slowly from east to west in
the night sky. This keeps them in the eyepiece eld of view
indenitely, instead of drifting out of sight.
• Barlow Lens – A 2x Barlow lens doubles the magnify-
ing power of any eyepiece it’s used with, giving you a big
power boost to get in closer to your target object. You just
insert it between the diagonal and the eyepiece.
• Planisphere – A nifty “star wheel” that shows what stars
and constellations are visible in the sky at any time of any
night. Just set the date and time see a mini representation
of your local night sky. Great for identifying what you see
and planning an evening’s observing session.
• Star Map – More detailed than a planisphere, a star
map is essential for locating interesting celestial objects
to observe with your telescope. Nowadays many mobile
astronomy apps feature customizable star maps that you
can access on your smartphone or tablet while you’re at
the telescope.
7. Telescope Care and
Maintenance
If you give your telescope reasonable care, it will last a lifetime.
Store it in a clean, dry, dust-free place, safe from rapid changes
in temperature and humidity. Do not store the telescope out-
doors, although storage in a garage or shed is OK. Small compo-
nents like eyepieces and other accessories should be kept in a
protective box or storage case. Keep the dust cover on the front
of the telescope when it is not in use.
Your refractor telescope requires very little mechanical mainte-
nance. The optical tube has a smooth painted nish that is fairly
scratch-resistant. If a scratch does appear on the tube, it will not
harm the telescope. If you wish, you may apply some auto touch-
up paint to the scratch. Smudges on the tube can be wiped off
with a soft cloth and household cleaning uid.
Cleaning Optics
Any quality optical lens cleaning tissue and optical lens cleaning
uid specically designed for multi-coated optics can be used
to clean the lenses of your telescope and eyepieces. Never use
regular glass cleaner or cleaning uid designed for eyeglasses.
Before cleaning, remove any loose particles or dust from the lens
with a blower bulb or soft brush. Then apply some cleaning uid
to a tissue, never directly on the optics. Wipe the lens gently in
a circular motion, then remove any excess uid with a fresh lens
tissue. Oily ngerprints and smudges may be removed using this
method. Use caution; rubbing too hard may scratch the lens. On
larger lenses, clean only a small area at a time, using a fresh
lens tissue on each area. Never reuse tissues.
When bringing the telescope inside after an evening’s viewing
it is normal for moisture to accumulate on the lenses due to the
change in temperature. We suggest leaving the telescope and
eyepieces uncovered overnight to allow the condensation to
evaporate.
8. Specifications
Objective lens: 80mm (3.1") diameter, achromatic
Effective focal length: 400mm
Focal ratio: f/5
Lens coatings: Fully antireection coated
Focuser: Rack-and-pinion, accepts 1.25" accessories
Eyepieces: 25mm Kellner and 10mm Plossl, 1.25" barrel
diameter, threaded for Orion lters
Eyepiece coatings: Fully antireection coated
Diagonal: Mirror, 1.25"
Eyepiece magnication: 16x (with 25mm eyepiece) and 40x
(with 10mm eyepiece)
Finder scope: Red dot nder scope, two brightness levels
Mount: German equatorial
Tripod: Aluminum
Motor drive: Optional
Total instrument weight: 15 lbs. 9 oz.

Orion CT80 Specifications

General

Brand	Orion
Model	CT80
Category	Telescope
Language	English