Star light, star bright...
Rich Wells, N2MCA
Do You Know What Incredible Things Are Out There To See?
- Stars (of all kinds of colors and intensities)
- Double/Triple/Quadruple star systems
- Variable stars
- Open star clusters
- Globular clusters
- The Moon
- Galaxies
- Nebula (emmision, reflection, dark, planetary)
- Planets & their moons
- Asteroids
- Comets
- Meteor Showers
- An occasional plane or satellite!
What Do I Need To See It?
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A lot can be seen with the naked eye alone! Honest! Just take the time to
slowly look around on a clear night and you'll see. You can make out fuzzy
patches of star clusters and even pick out the planets(most can be seen but
they look like colored stars). See anything interesting?
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Buy a good book and/or star map to learn the constellations and how to
recognize planets.
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Once you know the constellations, you'll be able to use them to help you find
the great sights in and around them. Buy a good pair of binoculars (Bushnell,
Pentax, Minolta, Nikon) in the $75 to $150 price range. A good "size" for
astronomy purposes will be 7x50...the '7' refers to the magnification while the
'50' refers to the lens diameter in millimeters. And just like telescopes, the
larger the lens, the more objects you can see due to the increased light
gathering capability
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If you are still interested at this point, it's time to hook up with a local
astronomy club (see below) to find out what type of telescope will fit your
budget and needs.
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Above all, DO NOT BUY A TELESCOPE FROM A DEPARTMENT STORE OR TV SHOW! They are
made of cheap parts and plastic lenses. They are designed to lure you in with
photos of stuff you can't see with it. The mounting and accessories are feeble
and wobbly. If the package claims magnifications of 400 or more, this is a SURE
SIGN of them trying to sucker you in. You'll get very discouraged and give up
instead of fulfilling a lifetime of observing the heavens!
Hook Up With A Local Astronomy Club
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Make use of the club's knowledge base and experience that can answer your every
qustion.
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You'll be able to accompany them on field trips to learn more about the hobby,
the equipment and accessories used and determine what you do and don't want to
spend you hard-earned money on!
Telescopes
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Telescopes come in all kinds of types, sizes and cost. Prices for amateur
instruments can go as high as $10,000 or more!
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For a decent telescope that will do right by you, expect to spend AT LEAST $350
for a new one and $250 used. Anything less than this will probably have a
wobbly mount and poor lenses. Both of which are examples of what you DON'T want
for a piece of equipment used to capture light and magnify an image.
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Telescopes are primarily measured by the diameter of their largest light
gathering optic. This is called the objective and can be made of a piece of
glass or a miror. The larger the objective, the more light can be "gathered",
hence fainter objects can be seen. At night, using the naked eye, it is your
objective and measures approximately 5 to 7mm. Smaller objectives are usually
measured in millimeters while larger ones are usually in inches.
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The basic telescope types consist of the refractor, reflector (Newtonian and
Dobsonian) and compound (Schmidt and Maksutov).
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The refractor objective is made of glass. A well made refractor can give the
finest images but also cost the most per inch of its objective. This means most
refractors you see out there are are in the 70mm (2.8") to 150mm (6") range.
Most of the "cheapo" scopes in the department stores are 60mm while others are
of the 3.5" - 4.5" Newtonian reflector variety.
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The reflector, as you might guess, reflects light and therefore uses a mirror
as its objective. It actually uses two mirrors referred to as the
primary (objective) and the secondary. Reflectors can give very good images and
tend to run in the middle price ranges. They are typically the best value for
the dollar but also the largest in terms of tube length.
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The compund telescopes use a combination of lenses and mirrors. Due to their
complexity, the tend to be expensive but are usually very portable when
compared with telescopes of similar sized objectives. Compound telescopes can
give very good images when properly made.
How Does A Telescope Work?
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The job of the objective is to collect a "column" of light into a point
source (kind of like the opposite of what a flashlight does). You then use an
eyepiece to magnify this point source to view your image. Think of your
binoculars for a second. The lens up front is the objective which is collecting
light (ever notice how objects at dusk look brighter?) The lens near your eye
is an eyepiece that magnifies the image and through the miracle of
optics...poof...things look closer!
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Eyepieces come in many different sytles and prices. They are composed of
anywhere from 2 to 8 glass elements and are typically measured in terms of
their focal length. This is an optical term used to indicate the physical
distance over which the lens or mirror does its job. Since a telescope has a
lens or mirror, its focal length can also be measured.
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The eyepiece functions like the reverse of the telescope in that it takes the
image formed by the objective and magnifies it. The amount of magnification
depends on the combination of telescope and eyepiece. The telescope's focal
length is fixed due to the very nature of its singular objective. But you can
buy eyepieces of different focal lengths! The magnification for a particular
pairing of telescope and eyepiece is calculated by dividing the focal length of
the telescope by the focal length of the eyepiece.
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A barlow lens is basically a special eyepiece whice is used to increase the
focal length of the telescope. By increasing the focal length of the telescope,
you are effectively increasing the resultant magnification. If a certain
eyepeice usually gives you a magnification of 50, a 2x barlow will multiplty
the normal magnification by a factor of 2! If you have three eyepieces for your
telescope (giving three separate magnifications) and you then buy a barlow, you
have effectively doubled the number of magnifications available...three when
using the eyepieces by themselves and three more for using each eyepiece with
the barlow!
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Now that you have the basics of telescopes, you can understand that a pair of
binculors is really two small refractor telescopes fastened together. You can
also understand why they are such a valuable tool for astronomy!
Find These Publications At Your Newsstand
My Observing Equipment
My Eyepiece Collection
- Meade 6.4mm Super Plössl
- Tele Vue 9mm Nagler
- Bausch & Lomb 10mm Plössl
- Celestron 10mm SMA
- Celestron 12.5mm Orthoscopic
- Tele Vue 15mm Wide Field
- Celestron 18mm Orthoscopic
- Tele Vue 21mm Plössl
- Celestron 25mm SMA
- Tele Vue 26mm Plössl
- Tele Vue 32mm Plössl
- Tele Vue 35mm Panoptic
- Tele Vue 40mm Plössl
- Celestron 2x barlow
- Meade 2x "shorty" barlow
- Tele Vue 1.8x barlow
- Tele Vue 2.0x barlow
- Tele Vue 2.5x barlow
- Tele Vue 3.0x barlow
Great Books & Star Maps
- 1000+ The Amateur Astronomer's Field Guide to Deep Sky Observing
by Lorenzin & Sechler
- Burnham's Celestrial Handbooks
by Robert Burhnam, Jr.
- Collins Stars & Planets
- Deep Sky Field Guide to Uranometria
by Cragin, Lucyk & Rappaport
- Golden Books Sky Guide
- How To Use An Astronomical Telescope
by James Muirden
- Observing Handbook and Catalogue of Deep-Sky Objects
by Luginbuhl & Skiff
- Peterson's Field Guide To the Stars and Planets
- Sky Atlas 2000.0
by Wil Tirion
- Sky Catalogue Vols. 1 & 2
by Hirshfeld & Sinnott
- Start-Hopping
by Robert Garfinkle
- Star Ware
by Philip S. Harrington
- The Backyard Astronomor's Guide
by Dickson & Dyer
- Touring the Universe through Binoculars
by Philip S. Harrington
- Turn Left at Orion
by Consolmagno & Davis
- Uranometria 2000.0 Vols. 1 & 2
by Tirion, Rappaport & Lovi
- Visual Astronomy of the Deep Sky
by Roger N. Clarke
Good Astronomy Web Pages
Good Astronomy USENET Groups
Questions? Comments? Send e-mail to [email protected]
Last updated March 26, 2004
Copyright © 2001 by Richard J. Wells
