Product Catalog
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What is it? A long tube with a lens at the front and an eyepiece
at the back.
What About It? This oldest of telescope designs is also the
most familiar. Galileo used one to discover the moons of Jupiter
in the year 1610. Refractors capture light with a lens that focuses
it at the back of the tube. They are famous for beautifully sharp,
unobstructed views. They are also the most expensive telescopes
per inch of aperture.
Who Uses Them? Refractors are a durable and reliable choice
for beginners in smaller apertures. Larger refractors are prized
by astrophotographers and serious observers for superb wide-
eld, high-contrast images.
For What? Excellent for bright objects like the Moon, planets,
double stars, clusters. Good for light-polluted city stargazing
and daytime land viewing. Aperture limitations make
refractors a secondary visual choice for faint deep sky nebulas,
clusters and galaxies. However, they are prized for wide-eld
astrophotography (see pg. 104).
Meade Scopes Available: Achromatic Refractors: ETX-80
(pg. 16), 5" and 6" LXD75 AR (pg. 40), 70AZ-AR and DS-
2080 (pg. 109). Apochromatic Refractors: 80mm and 127mm
Series 5000 ED APO Refractors (pg. 100).
Achromatic:
Achromatic Refractors have two lenses with a thin air space in between
them. This simple design is very effective and affordable. Because
residual color (due to unequal focusing of different colors by the
lens glass) can cause a slight halo around bright objects and the
moon, more expensive Apochromatic refractors were developed.
Apochromatic:
Apochromatic Refractors use two (or preferably three) elements of
a much more expensive extra-low dispersion (ED) glass to color-
correct the image and eliminate color fringing. Meade’s triplet
design does this especially well (see pg. 100). These instruments offer
some of the finest views in all astronomy at their respective apertures.
a s t r o p h o t o g r a p h y : j a s o n w a r e / m o o n / l x 4 0 0
TELESCOPES 101. A basic guide to optical systems.
Optical Systems
EXHIBIT 3