Although the power is variable, each instrument under average skies has a limit to the highest useful magnification. The general rule is that 60 power
can be used for every inch of aperture. For example, the C90 is 3.5 inches in diameter. Multiplying 3.5 by 60 gives a maximum useful magnification
of 210 power. Although this is the maximum useful magnification, most observing is done in the range of 20 to 35 power for every inch of aperture
which is 70 to 123 times for the C90 spotting scope. Lower powers give you brighter images but experiment to see what is best for you.
A
A
t
t
t
t
a
a
c
c
h
h
i
i
n
n
g
g
a
a
C
C
a
a
m
m
e
e
r
r
a
a
1.
T-Adapter threads are built into the rear of the spotting scope (see right portion of image to the left). With a camera
specific T-ring, a Digital SLR (or SLR) camera can be attached to the spotting scope.
2.
Remove the erect image diagonal and eyepiece from the rear cell of the tube.
3.
Thread the T-Ring onto the rear opening which contains the threads (T-Adapter) – see image to the left.
4.
Mount your camera body onto the T-Ring the same as you would any other lens.
Note:
Since digital cameras (not digital SLR cameras) do not use the T-system to mount cameras to lenses, spotting
scopes, telescopes, etc. you need a different way to be able to use them to take photos. Celestron offers a Universal
Digital Camera Adapter (Model # 93626) which makes it easy to attach most digital cameras to your spotting scope.
M
M
a
a
i
i
n
n
t
t
e
e
n
n
a
a
n
n
c
c
e
e
T
T
o
o
p
p
r
r
o
o
t
t
e
e
c
c
t
t
y
y
o
o
u
u
r
r
s
s
p
p
o
o
t
t
t
t
i
i
n
n
g
g
s
s
c
c
o
o
p
p
e
e
w
w
h
h
e
e
n
n
n
n
o
o
t
t
b
b
e
e
i
i
n
n
g
g
u
u
s
s
e
e
d
d
,
,
p
p
u
u
t
t
o
o
n
n
a
a
l
l
l
l
l
l
e
e
n
n
s
s
c
c
o
o
v
v
e
e
r
r
s
s
a
a
n
n
d
d
c
c
a
a
p
p
s
s
t
t
o
o
k
k
e
e
e
e
p
p
t
t
h
h
e
e
o
o
p
p
t
t
i
i
c
c
s
s
c
c
l
l
e
e
a
a
n
n
a
a
n
n
d
d
t
t
h
h
e
e
n
n
p
p
u
u
t
t
t
t
h
h
e
e
s
s
c
c
o
o
p
p
e
e
i
i
n
n
i
i
t
t
s
s
b
b
a
a
c
c
k
k
p
p
a
a
c
c
k
k
.
.
I
I
f
f
y
y
o
o
u
u
r
r
o
o
p
p
t
t
i
i
c
c
s
s
c
c
o
o
u
u
l
l
d
d
u
u
s
s
e
e
c
c
l
l
e
e
a
a
n
n
i
i
n
n
g
g
,
,
u
u
s
s
e
e
a
a
n
n
o
o
p
p
t
t
i
i
c
c
s
s
c
c
l
l
e
e
a
a
n
n
i
i
n
n
g
g
k
k
i
i
t
t
a
a
n
n
d
d
f
f
o
o
l
l
l
l
o
o
w
w
t
t
h
h
e
e
i
i
n
n
s
s
t
t
r
r
u
u
c
c
t
t
i
i
o
o
n
n
s
s
.
.
Warranty
Celestron Spotting Scopes have the Celestron No Fault Limited Lifetime Warranty for the U.S.A. and Canadian customers.
For complete details of eligibility and for warranty information on customers in other countries visit the Celestron website.
2835 Columbia St.
Torrance, CA 90503 U.S.A.
www.celestron.com
©2010 All Rights Reserved
Printed in China 01-10
SPECIFICATIONS
52268
C90 Spotting Scope
Optical Design
Maksutov-Cassegrain
Aperture
90mm
(3.5”)
Focal Length
1250mm
Focal Ratio
f/13.9
Optical Coatings
Multi-Coated
Finderscope, Erect Image
8x21
Eyepiece - 1.25” Plossl
32mm (39x)
Angular Field of View
1.3° w/32mm
Linear FOV – ft@1000yds / m@1000m
w/32mm – 68/23
Eye Relief
20mm
Near Focus
15 feet (4.6m)
Length w/diagonal & eyepiece
16”
(41cm)
Weight w/diagonal & eyepiece
5# (2.3Kg)
Note: Specifications subject to change without notice or obligation
