Setting Circles - Meade 2080 Instruction Manual

-31-
To actuate operation of the electric motor drive, the
R.A. lock (see (5), Fig. l)must be in the "locked" posi-
tion. As you move from object to object, unlocking and
re-locking the R.A. lock each time, the motor drive auto-
matically re-actuates each time the R.A. lock is locked.
NOTE: DO NOT ATTEMPT TO TURN THE R.A. SLOW-MOTION CONTROL
KNOB WHEN THE R.A. LOCK IS IN THE "LOCKED" POSITION. SUCH
AN OPERATION WILL CAUSE INTERNAL DAMAGE TO THE GEARS OF THE
R.A. SLOW-MOTION CONTROL. IN ADDITION, DO NOT ATTEMPT TO
TURN THE TELESCOPE MANUALLY ON ITS FORK MOUNT IN R.A. WHEN
THE R.A. LOCK IS "LOCKED,"
AS SUCH
OPERATION WILL CAUSE
RAPID WEAR OF THE INTERNAL CLUTCH SYSTEM.
SETTING CIRCLES
Setting circles included with the Models 2080 and 2120 per-
mit the location of faint celestial objects not easily
found by direct visual observation. Located on the "top
surface of the telescope's drive base-, the R.A. circle (12)
r
Fig. 1,. is 8" in diameter. Identical Declination circ~es
(3), Fig. 1, are located at the top of each fork tine.
with the telescope pointed at the North Celestial POle,
the Dec. -circle should read 900 (understood to mean +900).
Objects located .below the 0-0 line of the Dec. circle
carry minus Declination coordinates. Each division of
the Dec. represents a 10 incrementfi The R.A. circle runs
from Ohr to. (but not including) 24 r, and reads in incre-
ments of Sm1n.
i
)
.
f
if
fA
:
{
,-.
.
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Note that the R.A. circle is double-indexed; i.e. there are
2 series of numbers running in opposite directions around
the circumference of the R.A. circle. The outer series of
numbers (increasing counterclockwise) applies to observers
located in the Earth's Northern Hemisphere; the inner series
of numbers (increasing clockwise) applies to observers
located in the Earth' s So_utl1~_~_n Hemisphere.
with the telescope aligned to the pole, center an object
of known R.A. in the telescopic field. Then turn the R.A.
circle, which can be rotated manually, until the R.A.
-
coordinate of the object is correctly indicated by the
R.A. pointer. As long as the telescope's motor drive
remains "ON," the R.A. pointer will then correctly indicate
the R.A. of any object at which the telescope is pointed
throughout the duration of the observing session.
To use the circles to locate a particular object first
look up the celestial coordinates (R.A. and Dec.) of the
object in a star atlas. Then loosen the R.A. lock and
turn the telescope to read the correct R.A. of the desired