Sky-Watcher EQ2 MOUNT - Manual (Page 15)

15
Fig.j
Southern Hemisphere
In the Southern Hemisphere you must align the mount to the SCP
by locating it's position with star patterns, without the convenience
of a nearby bright star. The closest star is the faint 5.5-mag. Sigma
Octanis which is about one degree away. Two sets of pointers which
help to locate the SCP are alpha and beta Crucis (in the Southern
Cross) and a pointer running at a right angle to a line connecting
alpha and beta Centauri (Fig.j).
omega
Oc
tanis
alpha
Centauri
beta
Centauri
alpha
Crucis
beta
Crucis
SCP +
0 1 23
23
1
2 22
3 21
4 20
5 19
6 18
7
17
8
16
9
15
10
14
Pointer
R.A. Setting Circle
R.A. lock knob
EQ1
U
sing the setting circles
The quickest way to find objects is to learn the
Constellations and use the Red Dot Finder, but if the object
is too faint you may want to use setting circles on your
mount. Setting circles enable you to locate celestial objects
whose celestial co-ordinates have been determined from
star charts.
Your telescope must be polar aligned and the R.A. setting
circle must be calibrated before using the setting circles. The
DEC. setting circle was set at the factory, and does not require
calibrating the same manner as the R.A. setting circle.
Reading the R.A. setting circle
The telescope's R.A. setting circle is scaled in hours, from 1
through 24, with small lines in between representing 10
minute increments. The upper set of numbers apply to
viewing in the Northern Hemisphere, while the numbers
below them apply to viewing in the Southern Hemisphere
(Fig.k).
Setting (calibrating) the R.A. setting circle
In order to set your Right Ascension circle you must first find
a star in your field of view with known coordinates. A good
one would be the 0.0 magnitude star Vega in the
Constellation Lyra. From a star chart we know the R.A.
coordinate of Vega is 18h 36m. Loosen the R.A. and DEC. lock
knobs on the mount and adjust the telescope so that Vega is
centred in the field of view of the eyepiece. Tighten the R.A.
and DEC. lock knobs to lock the mount in place. Now rotate
the R.A. setting circle until it reads 18h36m. You are now
ready to use the setting circles to find objects in the sky.
T
racking Celestial Objects
When observing through a telescope, astronomical objects appear to move slowly through the telescope's field of
view. When the mount is correctly polar aligned, you only need to turn the R.A. slow-motion to follow or track objects
as they move through the field. The DEC. slow-motion control is not needed for tracking. A R.A. motor drive can be
added to automatically track celestial objects by counteracting the rotation of the Earth. The rotation speed of the R.A.
drive matches the Earth's rotation rate for stars to appear stationary in the telescope eyepiece. Different tracking
speeds are also available in some models. A second drive can be added to give DEC control which is very useful for
doing astrophotography.
Fig.k
Pointer
R.A. Setting Circle
R.A. lock knob
EQ2
17
7
16
8
15
9
14
10
13
11
18
6
19 5
20 4
21 3
22 2
231
0