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d. In the very rare situation where cleaning the inside surface of the corrector lens becomes necessary,
unthread the lens cell located at the front of the main tube. The entire correcting lens and secondary mirror
system is mounted in this cell. The lens cleaner solution described in Step c. may be used to clean the
inside surface of the lens. DO NOT use a commercial photographic lens cleaner
CAUTION: Do not touch the aluminized circular surface of the secondary mirror with your finger, a tissue,
or any other object. Scratching of the mirror surface will otherwise almost certainly result
Note: When cleaning the inside surface of the correcting lens, leave the lens mounted in its metal cell
throughout the process. Do not remove the lens from its metal housing or else optical alignment of the lens
will be lost, necessitating a return of the telescope to the Meade factory.
e. If the ETX is used outdoors on a humid night, water condensation on the telescope surfaces will probably
result. While such condensation does not normally cause any damage to the telescope, it is recommended
that the entire telescope be wiped down with a dry cloth before the telescope is packed away. Do not,
however, wipe any of the optical surfaces. Rather, simply allow the telescope to sit for some time in the
warm indoor air, so that the wet optical surfaces can dry unattended.
f.
If the ETX Telescope is not to be used for an extended period, perhaps for one month or more, it is
advisable to remove the three AA-batteries from inside the drive base. Batteries left in the circuit board for
prolonged periods may leak, causing damage to the telescope's electronic circuitry.
g. The super-gloss anodized finish of the ETX's deep-violet optical tube will fade if left in direct sunlight for
prolonged periods.
h. Do not leave the ETX telescope inside a sealed car on a warm summer day; excessive ambient
temperatures can damage the telescope's internal lubrication and electronic circuitry.
A set of three (English-format) hex wrenches is provided with each ETX Astro Telescope. These wrenches are
used as follows:
Small wrench (.050"): Use the small wrench to tighten the set-screws of any knobs which may loosen (e.g., the
Dec Slow-Motion Control knob, Focus knob, R.A. Lock, R.A. Slow-Motion Control knob, or Flip-Mirror Control
knob).
Medium wrench (1/16"): This wrench is used to detach the viewfinder bracket from the telescope's rear-cell.
Large wrench (7/64"): The large wrench is used to detach the ETX optical tube assembly from its fork mount,
permitting placement of the tube assembly on a standard photo tripod.
2. Storage and Transport
When not in use, store the telescope in a cool, dry place. Do not expose the instrument to excessive heat or
moisture. It is best to store the telescope in its original box. If shipping the telescope, use the original box and
packing material to protect the telescope during shipment. When transporting the telescope, take care not to bump
or drop the instrument; this type of abuse can damage the optical tube and/or the objective lens.
3. Inspecting the Optics: A Note About the "Flashlight" Test:
If a flashlight or other highintensity 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 appears to be scratches, dark or bright spots,
or just generally uneven coatings, giving the appearance of poor quality 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
optical 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.
4. Troubleshooting
The following suggestions may be helpful if you are having difficulty observing objects through the ETX Astro
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