Astronomy - June 2015

62 ASTRONOMY • JUNE 2015

EQUIPMENT REVIEW

L

ike many observers I’ve talked to

through the years, I always have

had a special place in my heart for a

small refractor. Refracting telescopes

use lenses to bring light to a focus

and are the oldest type of telescope. While

the inventor of the refractor is a matter of

debate, Hans Lipperhey, a German-Dutch

spectacle maker, filed the first known pat-

ent application October 2, 1608.

Early refractors typically required a

large (or slow) focal ratio — which trans-

lates to a really long tube — to keep false

color under control. Such instruments were

a bit unwieldy, especially if there was any

wind. Major improvements followed: the

achromatic lens (in 1733), the apochro-

matic lens (in 1981), and various formulas

for types of low-dispersion glass.

As amateur astronomers, we are lucky

to live in a world where we have a plethora

of choices in telescopes. We use them both

as camera lenses and visual instruments.

Refractors excel at wide fields, but good

ones also take magnification well. They are

portable, durable, and — when well treated

— do not require collimation (alignment).

Finally, I prefer a small refractor to large

binoculars for one major reason: the f lex-

ibility to change magnification.

The tiny titan

Speaking of small telescopes, Auburn,

California-based Stellarvue recently intro-

duced a new, ultra-portable apochromatic

refractor that I suggest you take a careful

look at. If you’re an experienced observer,

this could become your new grab-and-go

scope. If, on the other hand, you’re new

to astronomy, this scope will help you get

into the hobby simply and inexpensively.

The Stellarvue SV60EDS is a 2.4-inch

(60 millimeters) refractor that has an apo-

chromatic doublet (two lenses that reduce

color) as its objective. Specifications indi-

cate that Stellarvue uses high-quality

(FPL–53) glass for one of the lens’ elements.

The scope’s focal length measures 330mm,

which yields a focal ratio of f/5.5.

The SV60EDS sports a rotating 2" rack-

and-pinion focuser with a dual-speed

mechanism. Stellarvue includes a 1¼"

adapter, and compression fittings are stan-

dard. The scope also comes with a clam-

shell adapter with finder bracket, a mini

Vixen-style dovetail plate, a well-padded

soft carry case with room for three eye-

pieces (or two eyepieces and the optional

field f lattener), a star diagonal, and a tube

extension for those wishing to use the tele-

scope for wide-field photography.

The lens cap is metal and a press fit.

The optical tube looks great — white pow-

der coat with black anodized fittings. The

telescope, clamshell, and included accesso-

ries weigh just 3.8 pounds (1.7 kilograms).

Stellarvue’s attention to detail impressed

me: The rubber cover on the clamshell

lever, the ¼–20 hole in the dovetail plate for

direct attachment to camera tripods, and

thumbscrews with non-marring tips are all

examples of the thought that went into the

We test

Stellarvue’s

compact refractor

This 2.4-inch scope is so

portable that you’ll use it

night and day. by Tom Trusock

Tom Trusock observes regularly despite the

often cloudy skies above Ubly, Michigan.

Stellarvue’s SV60EDS is a compact apochromatic

refractor. These images show the telescope fully

retracted (left, 8.5 inches [21.6 centimeters]) and

extended (12.5 inches [31.8cm]). ALL EQUIPMENT PHOTOS:

ASTRONOMY: WILLIAM ZUBACK