Leisure Time LX20 - Manual (Page 50)

APPENDIX E: MAINTAINING YOUR LX200
1. Keeping Your Telescope Clean
Prevention is the best recommendation that a telescope owner
can follow to keep astronomical equipment in top working order.
Proper measures taken during observation and when storing
equipment between observing runs can add many years of trouble
free use.
Dust and moisture are the two main enemies to your instrument.
When observing, it is advisable to 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 buildup,
there can be times when the telescope optics will have a uniform
coating of moist dew. This is not particularly harmful, as long as
the instrument is allowed to let the dew evaporate. This can be
done with a hair dryer, or just setting up the telescope indoors with
the dust covers removed. It is also advisable that you let the foam
lined case for the LX200 dry out indoors for a day if the night was
moist. Packing your telescope away in a moist case can result in
giving it a steam bath later.
If you live in a very moist climate, you may find it necessary 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.
Those living in coastal areas or tropic zones should also cover the
electronic ports on the power panel and the keypad with gaffers
tape to reduce corrosion on the metal contacts. Apply a dab of a
water displacement solution (i.e. WD-40) with a small brush on all
interior metal contacts and the input cord metal contacts. The
keypad and all separate accessories should be kept in sealable
plastic bags with silica desiccant.
A thick layer of dust will attract and absorb moisture on all
exposed surfaces. Left unattended, it can cause damaging
corrosion. To keep dust at bay when observing, the telescope can
be set up on a small section of indoor/outdoor carpet. If you are
observing for more than one night in a row, the telescope can be
left set up but covered with a large plastic bag (such as the one
supplied with the telescope). The rear cell opening of the LX200
can also be sealed off to 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.
All of the non optical surfaces of the LX200 should be cleaned
routinely with a soft rag and alcohol to prevent corrosion. The cast
metal surfaces and the individual exposed screws can also be kept
looking new and corrosion free by wiping them down with a water
displacement solution. Take care not to smear the solution onto
any optical surface, and to wipe up any excess solution with a
clean dry cloth. The painted tube can be polished with a liquid car
polish and a soft rag.
Surprisingly, the most common telescope maintenance
error is cleaning the optics too often. A little dust on any of
the optical surfaces causes virtually zero degradation of optical
performance. It should be of no concern whatsoever to see
some small particles on the inside or outside of telescope optics.
Should the optics get more dust on them than you would care for,
simply 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, however, when the optics must be cleaned. This
is when you can easily tell that there is a thin layer of fine
particulates that make the optics look very slightly hazy. To clean
the optics we must suggest that you 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 better)
will clean most residual film build-up on optical surfaces (and metal
surfaces too).
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.
Sprayer bottles are a convenient dispenser of lens cleaning
solutions onto the tissues. Use soft, white facial tissues and make
short, gentle strokes. Change tissues often. If the optics are small
(such as viewfinders or eyepieces), the tissue can be rolled to the
appropriate thickness and then broken in half to create two
cleaning wands. It is advised that you avoid many of the so-called
lens cleaning papers (many which contain fiberglass), lens cloths,
or chamois.
Before attempting to clean an optical surface with a liquid solution,
it is very important that as much dust as possible is removed by
using 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. Be sure to hold the canned air in a vertical position and try
spraying compressed air on your hand before aiming at the optics
to see if any of the propellent (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 being sprayed on the
optics.
Once you are confident that 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 in 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 properly center and re-assemble the
optical train.
Use dry tissue to make the final clean up, again using no pressure.
If there is still some sort of residue, repeat the procedure using the
three part formula described above, again using the same
cleaning techniques.
The inside surface of the corrector plate and secondary mirror
may at some point become dirty due to particles falling inside the
tube when removing or replacing the rear dust cover or threading
on accessories. To reduce the chance of interior contamination,
the Meade Skylight 1A Dust Seal is very effective. If the Dust Seal
is not used, it helps to have the rear cell pointed downward when
replacing the rear dust cover or attaching accessories.
Another more serious, but not damaging problem is the possibility
of a hazy (usually uneven) film building up on the inside of the
corrector plate. This can be caused by
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