Meade Instruments LX600 - Manual (Page 58)

AutoStar #497 HANDBOX
Appendix E
58
Setting Circles
Setting circles included with the LX600 ACF models permit
the location of faint celestial objects not easily found by direct
visual observation. The RA circle (Pg. 10, Fig. 1, 11 and
Fig. 20) is located on the top surface of the telescope’s drive
base. The Declination circle (Fig. 21) is located at the top of
the fork tine. With the telescope pointed at the North Celestial
Pole, the DEC circle should read 90° (understood to mean
+90°). Objects located below the 0-0 line of the DEC circle carry
minus Declination coordinates. Each division of the DEC circle
represents a 1° increment. The RA circle runs from 0hr to (but
not including) 24hr, and reads in increments of 5min.
Using setting circles requires a developed technique. When using
the circles for the fi rst time, try hopping from one bright star (the
calibration star) to another bright star of known coordinates.
Practice moving the telescope from one easy-to-fi nd object to
another. In this way, the precision required for accurate object
location becomes evident.
Note You may also enter an object’s RA and DEC coordinates
using the “User: Objects” option of AutoStar II’s Object menu.
AutoStar II then automatically slews the telescope to the entered
coordinates.
Note: The RA circle is double-indexed (i.e., there are two series of
numbers running in opposite directions around the circumference
of the RA circle). The upper series of numbers (increasing
counterclockwise) applies to observers located in the Earth’s
Northern Hemisphere; the lower series of numbers (increasing
clockwise) applies to observers located in the Earth’s Southern
Hemisphere.
To use the setting circles to locate an object not easily
found by direct visual observation:
With the telescope aligned to the Celestial Pole, fi rst look up
the celestial coordinates (RA and DEC) of the object in a star
atlas. Then loosen the RA lock and move the telescope to read
the correct RA of the desired object; lock the RA lock onto the
coordinate. Next, move the telescope in Declination to read the
correct Declination of the object. If the procedure has been
followed carefully, and if the telescope was well-aligned with the
pole, the desired object should now be in the telescopic fi eld of a
low-power eyepiece.
If you do not immediately see the object you are seeking, try
searching the adjacent sky area. Keep in mind that, with the
26mm eyepiece, the fi eld of view of the LX600 ACF is about
0.5°. Because of its much wider fi eld, the viewfi nder may be of
signifi cant assistance in locating and centering objects, after the
setting circles have been used to locate the approximate position
of the object.
Pinpoint application of the setting circles requires that the
telescope be precisely aligned with the pole. See PRECISE
POLAR ALIGNMENT, page 60.
X-Wedge
An optional equatorial X-Wedge is required for equatorial
(polar) alignment.
Note: The Meade X-Wedge is recommended for the 10" to
14" models.
The equatorial wedge permits use in an astronomical, or
“equatorial” mode. The wedge fi ts onto the fi eld tripod allowing
you to take longer exposure photographs with your LX600 ACF.
See the instruction sheet supplied with the wedge for installation
and setup information.
Note: For almost all astronomical observing requirements,
approximate settings of the telescope’s latitude and polar axis
Fig. 20. Section of RA setting circle.
Fig. 21. DEC setting circle.