7
The maximum attainable magnification for a telescope is
directly related to how much light it can gather. The larger the
aperture, the more magnification is possible. In general a fig-
ure of 50x per inch of aperture is the maximum attainable for
most telescopes. Your SkyView Pro 6LT EQ has an aperture
of 6 inches, so the maximum magnification would be about
300x. This level of magnification assumes you have ideal con-
ditions for viewing.
Keep in mind that as you increase magnification, the bright-
ness of the object viewed will decrease; this is an inherent
principle of the laws of physics and cannot be avoided. If mag-
nification is doubled, an image appears four times dimmer. If
magnification is tripled, image brightness is reduced by a fac-
tor of nine!
Start by centering the object being viewed in the 25mm eye-
piece. Then you may want to increase the magnification to get
a closer view. If the object is off-center (i.e., it is near the edge
of the field of view) you will lose it when you increase magnifi-
cation, since the field of view will be narrower with the higher-
powered eyepiece. To change eyepieces, first loosen the
securing thumbscrews on the focuser. Then carefully lift the
eyepiece out of the holder. Do not tug or pull the eyepiece to
the sides, as this will knock the telescope off its target.
Replace the eyepiece with the new one by sliding it gently into
the holder. Re-tighten the thumbscrews, and refocus for your
new magnification.
6. Setting Up and Using the
Equatorial Mount
When you look at the night sky, you no doubt have noticed
that the stars appear to move slowly from east to west over
time. That apparent motion is caused by the Earth’s rotation
(from west to east). An equatorial mount (Figure 6) is
designed to compensate for that motion, allowing you to easi-
ly “track” the movement of astronomical objects, thereby
keeping them from drifting out of your telescope’s field of view
while you’re observing.
This is accomplished by slowly rotating the telescope on its
right ascension (R.A.) axis, using only the R.A. slow-motion
knob. But first the R.A. axis of the mount must be aligned with
the Earth’s rotational (polar) axis—a process called polar
alignment.
Polar Alignment
For Northern Hemisphere observers, approximate polar
alignment is achieved by pointing the mount’s right ascension
axis at the North Star, or Polaris. It lies within 1° of the north
celestial pole (NCP), which is an extension of the Earth’s rota-
tional axis out into space. Stars in the Northern Hemisphere
appear to revolve around the NCP.
Figure 6.
The SkyView Pro Equatorial Mount, shown from both sides.
Dec. slow-motion
control knob
Dec. setting circle
Front opening
a.
b.
Polar axis
finder scope
Latitude scale
Latitude
adjustment
L-bolts
R.A.
setting circle
Dec. lock lever
R.A. lock lever
R.A. slow-motion
control knob
Big Dipper
(in Ursa Major)
Little Dipper
(in Ursa Minor)
Cassiopeia
N.C.P.
Poin
ter
Stars
Polaris
Figure 7.
To find Polaris in the night sky, look north and find the
Big Dipper. Extend an imaginary line from the two "Pointer Stars" in
the bowl of the Big Dipper. Go about five times the distance
between those stars and you'll reach Polaris, which lies within 1° of
the north celestial pole (NCP).
Rig
ht
As
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n
(R
.A.)
ax
is
D
ec
lin
at
io
n
(D
ec
.)
a
xi
s
Rig
ht
As
cen
sio
n
(R.A.) a
xis
De
clinatio
n (De
c.) a
xis
Summary of Contents for SKYVIEW PRO 6LT EQ 9872
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