Meade 2045 - Telescope Maintenance; Cleaning the Optics

astronomers talk almost constantly about the "seeing conditions," since, ironically, even the clearest,
darkest skies may be almost worthless for serious observations if the air is not steady. This steadiness of
the atmosphere is most readily gauged by observing the "twinkling" of the stars: rapid twinkling implies
air motion in the Earth’s atmosphere, and under these conditions, resolution of fine detail (on the surface
of Jupiter, for example) will generally be limited. When the air is steady, stars appear to the naked eye as
untwinkling points of unchanging brightness, and it is in such a situation that the full potential of the
telescope may be realized: higher powers may be used to advantage, closer double stars resolved as
distinct points and fine detail observed on the Moon and planets.
Several basic guidelines should be followed for best results in using your telescope:
1. Try not to touch the eyepiece while observing. Any vibrations resulting from such contact will
immediately cause the image to move.
2. Allow your eyes to become "dark adapted" prior to making serious observations. Night adaptation
generally requires about 10 to 15 minutes for most people.
3. Let the telescope "cool down" to the outside environmental temperature before making observations.
Temperature differentials between a warm house and cold outside air require about 30 minutes for the
telescope’s optics to regain their true and correct figures. During this period, the telescope will not
perform well. A good idea is to take the telescope outside 30 minutes before you want to start observing.
4. If you wear glasses and do not suffer from astigmatism, take off your glasses when observing through
the telescope. You can re-focus the image to suit your own eyes. Observers with astigmatism, however,
should keep their glasses on since the telescope cannot correct for this eye defect.
5. Avoid setting up the telescope inside a room and observing through an open window (or, worse yet,
through a closed window). The air currents caused by inside/outside temperature differences will make
quality optical performance impossible.
6. Perhaps most importantly of all, avoid "overpowering" your telescope. The maximum usable
magnification at any given time is governed by the seeing conditions. If the telescopic image starts to
become fuzzy as you increase power, drop down to a reduced magnification. A smaller but brighter and
sharper image is far preferable to a larger but fuzzy and indistinct one.
7. As you use your telescope more and more, you will find that you are seeing finer detail: observing
through a large aperture telescope is an acquired skill. Celestial observing will become increasingly
rewarding as your eye becomes better trained to the detection of subtle variations of resolution.
TELESCOPE MAINTENANCE
Cleaning the Optics
Perhaps the most common telescope maintenance error is cleaning the optics too often. A little dust on
the surface of the front correcting lens causes negligible degradation of optical performance; don’t clean
the outside surface of this lens unless really necessary. To remove small particles on the corrector lens
surface, use a camel’s hair brush (gently!) or blow off with an ear syringe (available from a local
pharmacy). If further cleaning is required, a photographic lens cleaner may be used. In any case, do not
clean the correcting lens by taking strong circular wipes with a piece of cloth or other material. Use a
white Kleenex-type tissue and make short, gentle radial wipes (from the center outward). Change tissues
several times when cleaning the entire lens surface.
Since all Model 2045 telescopes include a high-transmission magnesium fluoride coating on the
correcting lens, always take care during cleaning to avoid scratching this coating.
To clean the inside surface of the correcting lens, the entire correcting lens cell may be unthreaded from
the blue color main tube. Follow the same procedure to clean the inside lens surface as described above
and then re-thread the entire corrector lens in cell carefully back onto the blue main tube. Do not touch
or attempt to clean the secondary mirror surface, as scratches will almost certainly result! (The
secondary mirror is visible in the center of the correcting lens, when the correcting lens cell is unthreaded