Inspecting The Optics; Gauging The Movement Of The Telescope - Meade LX200GPS-SMT Technical Manual

Fig. 32: R.A. Lock.
Fig. 33: Dec. Lock.
46
i. As a final check of alignment, examine the star image in focus with the higher
power eyepiece as suggested (j), under good viewing conditions. The star point
should appear as a small central dot (commonly referred to as an "Airy disc") with
a diffraction ring surrounding it. To give a final precision collimation, make
extremely slight adjustments of the three set screws, if necessary, to center the
Airy disc in the diffraction ring. You now have the best alignment of the optics pos-
sible with this telescope.

Inspecting the Optics

A Note about the "Flashlight Test:" If a flashlight or other high-intensity light source
is pointed down the main telescope tube, the view (depending upon the observer's
line of sight and the angle of the light) may reveal what appear to be scratches, dark
or bright spots, or just generally uneven coatings, giving the appearance of poor qual-
ity optics. These effects are only seen when a high intensity light is transmitted
through lenses or reflected off the mirrors, and can be seen on any high quality opti-
cal system, including giant research telescopes.
The optical quality of a telescope cannot be judged by the "flashlight test;" the true test
of optical quality can only be conducted through careful star testing.

Gauging the Movement of the Telescope

A common complaint of many first-time motorized telescope owners is that they can-
not see the telescope "move" when the motor drive is engaged. If fact, when the bat-
teries are installed, the power is on and the R.A. lock (Fig. 32) engaged, the telescope
is moving. However, the movement is at the same speed as the hour hand of a 24-
hour clock; as such, the movement is difficult to discern visually.
To check the movement of your telescope, look at an astronomical object through the
telescope's eyepiece with the telescope aligned and with the motor drive on. If the
object remains stationary in the field of view, your telescope is operating properly. If
not, check to ensure that you have engaged the R.A. lock and that the power switch
on the control panel is on.
Meade Customer Service
If you have a question concerning your
Customer Service Department at:
Telephone: (949) 451-1450
Fax: (949) 451-1460
Customer Service hours are 8:30 AM to 4:30 PM, Pacific Time, Monday through
Friday. In the unlikely event that your
write or call the Meade Customer Service Department first, before returning the tele-
scope to the factory, giving full particulars as to the nature of the problem, as well as
your name, address, and daytime telephone number. The great majority of servicing
issues can be resolved by telephone, avoiding return of the telescope to the factory.
If factory service is required, you will be assigned a Return Goods Authorization
(RGA) number prior to return.
What is Smart Drive?
Smart Drive is a feature that allows you to train almost all of the periodic error from
the R.A. and Dec. motor drive worm gears. Periodic error is brought about by tiny
gear imperfections. These imperfections exist in all manufactured worm gears.
These imperfections tend to ever so slightly speed up or slow down the drive track-
ing speed during each rotation of the worm gear. This inconsistency in the tracking
rate can have a negative effect on astrophotography. Smart drive lets you train your
telescope system to compensate for these inconsistencies and, as a result, perform
more accurate tracking during astrophotography. Smart Drive remembers the train-
ing even after the telescope is turned off.
If you'd like to learn more about about Periodic Error Correction, see page 39.
, contact the Meade Instruments
LX200GPS
requires factory servicing or repairs,
LX200GPS
LX200GPS TIPS