Orion #8297 8" F/3.9 User Manual download pdf (Page 11)

cap on the eyepiece opening. Keep the telescope inside the

hard storage carrying case when not in use. Store it indoors

or in a dry garage. Do not leave the telescope outside except

when using it. The optical tube is aluminum and has a smooth

anodized surface that should resist scratches and smudges.

If a scratch does appear on the tube, it will not harm the tele-

scope. Smudges on the tube can be wiped off with standard

household cleaners such as Windex or Formula 409.

Cleaning Mirrors

In general, your telescope’s mirrors will only need to be

cleaned very infrequently, if ever. Covering the front opening

of the telescope with the dust cover when it is not in use will

prevent dust from accumulating on the mirrors. Keeping the

dust cap on the focuser’s 1.25" opening is also a good idea.

Improper cleaning can scratch the mirror coatings, so the

fewer times you have to clean the mirrors, the better. Small

specks of dust or flecks of paint have virtually no effect on the

visual or imaging performance of the telescope.

The large primary mirror and the elliptical secondary mirror of

your telescope are front-surface aluminized and over-coated

with hard silicon dioxide, which prevents the aluminum from

oxidizing. These coatings normally last through many years of

use before requiring re-coating.

To clean the secondary mirror, first remove it from the tele-

scope. Do this by keeping the secondary mirror holder sta-

tionary while completely unthreading the Phillips-head screw

in the center hub of the spider vane assembly (see Figure

11). Do not touch the mirror surface when doing this. Once

the Phillips-head screw is unthreaded, the secondary mirror

and its holder can be removed from the telescope. The sec-

ondary mirror does not need to be removed from its holder for

cleaning. Then follow the same procedure described below

for cleaning the primary mirror.

To clean the primary mirror, first carefully remove the mirror

cell from the telescope. To do so you must remove the screws

that attach the primary mirror cell and end ring to the tube

(Figure 16). Then pull the cell away from the tube. You will

notice the primary mirror is held in the mirror cell with three

clips held by two screws each. Loosen the screws and remove

the clips.

You may now remove the primary mirror from its cell. Do not

touch the surface of the mirror with your fingers. Lift the mirror

carefully by the edges. Set the mirror on a clean soft towel. Fill

a clean sink or large bucket with room temperature water, a

few drops of liquid dishwashing detergent, and if possible, a

capful of 100% isopropyl alcohol. Submerge the mirror (alu-

minized surface facing up) in the water and let it soak for a

few minutes (or hours if it’s a very dirty mirror). Wipe the mir-

ror under water with clean cotton balls, using extremely light

pressure and stroking in straight lines across the mirror sur-

face. Use one ball for each wipe across the mirror. Then rinse

the mirror under a stream of lukewarm water. Any particles

on the surface can be swabbed gently with a series of cotton

balls, each used just one time. Dry the mirror surface with a

stream of air (a “blower bulb” works great). Cover the mirror

surface with tissue, and leave the mirror in a warm area until

it is completely dry before replacing it in the mirror cell. Then

reinstall the mirror cell in the telescope optical tube with the

six screws.

Figure 16. To clean the primary mirror, it must first be removed

from the telescope tube. To do so, remove the Phillips-head screws

that fasten the rear cell and end ring to the telescope tube. Then

separate the cell from the tube.

Figure 15. A star test will determine if the telescope’s optics are

properly collimated. A defocused view of a bright star through the

eyepiece should appear as illustrated on the right if the optics are

perfectly collimated. If the circle is unsymmetrical, as illustrated on

the left, the optics need alignment.

Out of collimation Collimated

1 2 ... 6 7 8 9 10 11 12

Comments to this Manuals

No comments

Orion #8297 8" F/3.9 User Manual Page 11

Comments to this Manuals

Related products and manuals for Optical devices Orion #8297 8" F/3.9