APPENDIX D:
MAINTAINING YOUR LX200
Keeping Your Telescope Clean and Dr y
Preventive maintenance is the best course for keeping
astronomical equipment in top working order. The measures
taken when observing, and storing equipment between observing
runs can add years of trouble-free use.
Dust and moisture are the two main problems. When observing,
use a proper-fitting dew shield. The dew shield not only prevents
dew from forming, and dust from settling on the corrector-plate
lens, it prevents stray light from reducing image contrast.
Although dew shields go a long way to prevent moisture build-up,
there can be times when the telescope optics have a uniform
coating of moist dew. This is not particularly harmful, as long as
you let the dew evaporate. Use a hair dryer or just set up the
telescope indoors with the dust covers removed. Let the foam-
lined case for the LX200 dry indoors for a day if the night was
moist (packing your telescope away in a moist case can give it a
steam bath later).
If you live in a very moist climate, you may need to use silica
desiccant stored in the telescope’s case to ward off moisture and
the possibility of fungus growing on and within the coatings of the
optics. Replace the desiccant as often as necessary.
If you live in a coastal or tropical zone, cover the electronic ports
on the power panel and the keypad with gaffer’s tape to reduce
corrosion on the metal contacts. Apply a dab of a water-
displacement solution (e.g., WD-40) with a small brush on all
interior metal contacts and the input-cord metal contacts. Keep
the keypad and all separate accessories in sealable plastic bags
with silica desiccant.
A thick layer of dust will attract and absorb moisture on all
exposed surfaces. Left unattended, this can cause damaging
corrosion. To reduce dust when you are observing, set up the
telescope on a small section of indoor/outdoor carpet. If you are
observing for more than one night in a row, you can leave the
telescope set up but covered with a large plastic bag (such as the
one supplied with the telescope). You can seal off the rear cell
opening of the LX200 from the elements by threading on the
optional accessory Skylight 1A Dust Seal. Eyepieces, diagonals,
and other accessories are best kept in plastic bags and stored in
cases, such as the Meade #50 Accessory Case.
To prevent corrosion, routinely clean all the non-optical surfaces
of the LX200 with a soft rag and alcohol. You can also keep the
cast-metal surfaces and individual exposed screws looking new
and corrosion free by wiping them with a water-displacement
solution. Do not smear the solution onto any optical surface, and
wipe up any excess solution with a clean dry cloth. You can polish
the painted tube with a liquid car polish and a soft rag.
The most common telescope-maintenance error is cleaning
the optics too often. A little dust on any of the optical surfaces
causes virtually no degradation of optical performance. Some
small particles on the inside or outside of telescope optics are of
no concern. Should the optics get more dust on them than you
would care for, use a photographic-grade camel-hair brush, with
very gentle strokes. You can also blow off dust with an ear syringe
(available from a local pharmacy).
There is a point when the optics must be cleaned: when you can
easily see a thin layer of fine particulates that make the optics
look very slightly hazy. To clean the optics make your own lens-
cleaning solutions, since it is impossible to know all of the
ingredients used in commercial lens cleaners. Pure isopropyl
alcohol (90% or more) will clean most residual film build-up on
optical surfaces (and metal surfaces too).
The Three-Part Solution
You can remove organic materials (e.g., fingerprints) on 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.
Sprayer bottles are a convenient dispenser of lens-cleaning
solutions onto the tissues. If the optics are small (e. g . ,
viewfinders or eyepieces), you can roll the tissue to the approp-
riate thickness and then break it in half to create two cleaning
wands. Avoid the so-called lens cleaning papers (many contain
fiberglass), lens cloths, or chamois.
Before attempting to clean an optical surface with a liquid
solution, you must remove as much dust as possible with forced
air and/or gentle strokes with a photographic-grade camel-hair
brush. The forced-air can come from a rubber ear syringe, or
canned compressed air from a photographic supply store. Hold
the canned vertical and spray air on your hand before aiming at
the optics to see if any of propellant (solid material) comes out.
Propellant is very difficult to remove from optics, so take care not
to tip the can when using it. If you have access to a compressor
hose, be sure that it is filtered to prevent oil from spraying on the
optics.
Once you have removed most of the dust and large particles,
begin cleaning with the mixture described above. Pour or spray
enough solution onto a pillow or wand of tissue until it is quite
wet. If you are cleaning a corrector plate, use radial strokes with
a smooth pillow of tissue, starting from the center out, using no
pressure. If you are cleaning small optical surfaces, use the
rolled wands of tissue starting from the edges then spiraling in to
the center, again using no pressure. Never pour or spray the
solution onto the corrector plate or eyepieces themselves, as the
liquid may go behind or between lenses, where it is difficult or
impossible to reach. Never attempt to disassemble an eyepiece
to clean the inner elements, as you will certainly not be able to
center and re-assemble the optical train.
Use dry tissue for the final clean up, again using no pressure. If
some residue remains, repeat the procedure using the three-part
solution described above and the same cleaning techniques.
The inside surface of the corrector plate and secondary mirror
may become dirty from particles falling inside the tube when you
remove or replace the rear dust cover or when you thread on
accessories. To reduce the chance of interior contamination, the
Meade Skylight 1ADust Seal is very effective. If you do not use
the Dust Seal, have the rear cell pointed downward when you
replace the rear dust cover or when you attach accessories.
Another more serious, but still not damaging possibility is that of
a hazy (usually uneven) film building up on the inside of the
corrector plate. This can come from environmental pollutants or
temperature changes causing outgassing or water condensation
from the interior paint.
C AU T I O N : A ny time the LX200 is being stored or
transported, be sure to release the R.A. and Dec. locks,
to prevent serious damage to the drive gears.
CAUTION: Never attempt to wipe down dew-covered
o p t i c s . Dust and dirt may be trapped with the
collected dew; you may scratch the optics. After the
dew evaporates, you will most likely find the optics in
fine condition for the next observing session.
CAUTION: Do not use scented, colored, or lotioned
tissues;they can damage the optics.
