Orion XT8 CLASSIC, XT10 CLASSIC instruction manual Specifications, SkyQuest XT

rors, the better. Small specks of dust or flecks of paint have virtually no effect on the visual performance of the telescope.

The large primary mirror and the elliptical secondary mirror of your telescope are front-surface aluminized and overcoated with hard silicon dioxide, which prevents the aluminum from oxidizing. These coatings normally last through many years of use before requiring re-coating, which is easily done.

To clean the secondary mirror, it must be removed from the telescope. Do this by holding the secondary mirror holder sta- tionary with your fingers (don’t touch the mirror itself) while unthreading the Phillips head screw in the center hub of the 4-vaned spider. Completely unthread the screw from the hold- er, and the holder will come loose in your fingers. Be careful not to lose the spring on the Phillips head screw.

Handle the mirror and its holder carefully. You do not need to remove the secondary mirror from its holder for cleaning. To clean the secondary mirror, follow the procedure described below for cleaning the primary mirror.

To clean the primary mirror, carefully remove the mirror cell from the telescope. To do this, you must remove the screws that connect the entire mirror cell to the steel tube. These screws are located on the outer edge of the mirror cell.

Now, remove the mirror from the mirror cell by removing the three mirror clips that secure the mirror in its cell. Use a Phillips head screwdriver to unthread the mirror clip anchor screws. Next, hold the mirror by its edge, and remove it from the mir- ror cell. Be careful not to touch the aluminized surface of the mirror with your fingers. Set the mirror on a clean, soft towel. Fill a clean sink, free of abrasive cleanser, with room-temper- ature water, a few drops of liquid dishwashing detergent, and if possible, a capful of rubbing alcohol. Submerge the mirror (aluminized face up) in the water and let it soak for several minutes (or hours if it is a very dirty mirror). Wipe the mirror underwater with clean cotton balls, using extremely light pres- sure and stroking in straight lines across the surface. Use one ball for each wipe across the mirror. Then rinse the mirror under a stream of lukewarm water. Any particles on the sur- face can be swabbed gently with a series of clean cotton balls, each used just one time. Dry the mirror in a stream of air (a “blower bulb” works great), or remove any stray drops of water with the corner of a paper towel. Water will run off a clean sur- face. Dry the bottom and the edges with a towel (not the mirror surface!). Cover the mirror surface with tissue, and leave the entire assembly in a warm area until it is completely dry before reassembling the telescope.

7. Specifications

SkyQuest XT 6"
Primary mirror
focal length:	1200mm, standard optical glass
Primary mirror diameter:	150mm
Focal Ratio:	f/8.0
Focuser:	Rack and pinion, accepts 1.25"
	eyepieces
Optical tube material:	Rolled steel
Eyepiece:	25mm Sirius Plössl, fully coated
	with multi‑coatings, 1.25" barrel
	diameter
Magnification with
supplied eyepiece:	48x
Reflex Sight:	EZ Finder II
Reflex Sight Bracket:	Plastic bracket with dovetail base
Mirror coatings:	Aluminum with SiO2 overcoat
Minor axis of
secondary mirror:	34.5mm
Optical tube weight:	13.5 lbs.
Base weight:	20.9 lbs.
Tube length:	45.5"
Tube outer diameter:	7.25"
SkyQuest XT 8"
Primary mirror
focal length:	1200mm, standard optical glass
Primary mirror diameter:	203mm
Focal Ratio:	f/5.9
Focuser:	Crayford, accepts 2" eyepieces
	and 1.25" eyepieces with adapter
Optical tube material:	Rolled steel
Eyepiece:	25mm Sirius Plössl, fully coated
	with multi‑coatings, 1.25" barrel
	diameter
Magnification with
supplied eyepiece:	48x
Reflex Sight:	EZ Finder II
Reflex Sight Bracket:	Plastic bracket with dovetail base
Mirror coatings:	Aluminum with SiO2 overcoat
Minor axis of
secondary mirror:	47.0mm
Optical tube weight:	20.3 lbs.
Base weight:	20.7 lbs.
Tube length:	46.5"
Tube outer diameter:	9.25"

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