Meade ETX-90 User Manual - Page 42

MAINTENANCE 42 MAINTENANCE Your ETX model telescope is a precision optical instrument designed to yield a lifetime of rewarding observations. Given the care and respect due any precision instrument, the telescope will rarely require factory servicing or maintenance. Use the following guidelines: 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, remove dust from the front lens with gentle strokes of a camel-hair brush or blow it off with an ear syringe (available at any pharmacy). Do not use a commercial photographic lens cleaner. 3. You may remove organic materials (e.g., fingerprints) from the front lens 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, un-thread the lens cell located at the front of the main tube. The entire correcting lens and secondary mirror system are mounted in this cell. You may use the lens- cleaner solution described in step 3 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. This will almost certainly scratch the mirror surface. 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 optical alignment of the lens will be lost, necessitating a return of the telescope to the Meade factory. 5. If your ETX model 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 your ETX model 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 Assembling the tripod, page 5). 7. The super-gloss painted finish of any ETX model's deep-violet optical tube fades if left in direct sunlight for prolonged periods. 8. Do not leave your ETX model 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. Storage and Transport When the telescope is not in use, store it 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 with the vertical and horizontal locks (Pg. 13 , Fig. 3, 6 and 9) in the unlocked positions. 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 and knock the optics out of alignment. It is highly recommended to use an optional carry case to transport the telescope (see OPTIONAL ACCESSORIES, page 17). Inspecting the Optics A few words about the so-called "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