MAINTENANCE AND SERVICING
General Maintenance
The ETX-90EC is a precision optical instrument designed to yield a lifetime of
rewarding applications. Given the care and respect due any precision instrument,
the ETX-90EC will rarely, if ever, require factory servicing or maintenance.
Maintenance guidelines include:
1. Avoid cleaning the telescope's optics: a little dust on the front surface of
the telescope's correcting lens causes virtually no degradation of image
quality and should not be considered reason to clean the lens.
2. When absolutely necessary, dust on the front lens should be removed
with gentle strokes of a camel hair brush or blown off with an ear syringe
(available at any pharmacy). Do not use a commercial photographic lens cleaner.
3. Organic materials (e.g., fingerprints) on the front lens may be removed with a solution of 3 parts distilled
water to 1 part isopropyl alcohol. A single drop of biodegradable dishwashing soap may be added per pint
of solution. Use soft, white facial tissues and make short, gentle strokes. Change tissues often.
CAUTION: Do not use scented, colored, or lotioned tissues or damage could result to the
optics.
4. 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 3 may be used to clean the inside
surface of the lens.
CAUTION: Do not touch the aluminized circular surface of the secondary mirror with a finger, a
tissue, or any other object. Scratching of the mirror surface will 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.
5. If the ETX-90EC is used outdoors on a humid night, telescope surfaces may accumulate water
condensation. 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 being packed away.
Do not,
however, wipe any of the optical surfaces.
Rather, simply allow the telescope to sit for some time in warm
indoor air, so that the wet optical surfaces can dry unattended. In addition, the dust cap should not be
placed back on to the optical tube until the telescope is thoroughly dry.
6. If the ETX-90EC is not to be used for an extended period, perhaps for one month or more, it is advisable to
remove the eight AA-size batteries from inside the drive base. Batteries left installed for prolonged periods
may leak, causing damage to the telescope's electronic circuitry (see
Assembly Instructions
).
7. The super-gloss anodized finish of the ETX-90EC's deep-violet optical tube fades if left in direct sunlight for
prolonged periods.
8. Do not leave the ETX-90EC telescope outdoors on a warm day or inside a sealed car for an extended
period of time; excessive ambient temperatures can damage the telescope's internal lubrication and
electronic circuitry.
9. A set of two (English-format) hex wrenches is provided with each ETX-90EC Astro Telescope. These
wrenches are used as follows:
o
Small wrench (.05"):
Use the small wrench to tighten the set-screws of any knobs which may
loosen (e.g., the focus knob or flip-mirror control knob).
o
Medium wrench (1/16"):
This wrench is used to detach the viewfinder bracket from the telescope's
rear-cell.
WARNING! Never use the
Meade ETX-90EC Astro
Telescope to look at the Sun!
Looking at or near the Sun
will
cause
instant
and
irreversible
damage to
your eye. Eye damage is often painless,
so there is no warning to the observer
that damage has occurred until it is too
late. Do not point the telescope or its
viewfinder at or near the Sun. Do not
look through the telescope or its
viewfinder as it is moving. Children
should always have adult supervision
while observing.
