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Orion telescopes & Binoculars

89 Hangar Way, Watsonville, CA 95076

Customer Support Help Line (800) 676-1343 • Day or Evening

One-Year limited Warranty

This Orion AstroView 120ST Equatorial refractor is warranted against defects in materials or workman-
ship for a period of one year from the date of purchase. This warranty is for the benefit of the original 
retail purchaser only. During this warranty period Orion Telescopes & Binoculars will repair or replace, at 
Orion’s option, any warranted instrument that proves to be defective, provided it is returned postage paid 
to: Orion Warranty Repair, 89 Hangar Way, Watsonville, CA 95076. If the product is not registered, proof 
of purchase (such as a copy of the original invoice) is required.
This warranty does not apply if, in Orion’s judgment, the instrument has been abused, mishandled, or 
modified, nor does it apply to normal wear and tear. This warranty gives you specific legal rights, and you 
may also have other rights, which vary from state to state. For further warranty service information, con-
tact: Customer Service Department, Orion Telescopes & Binoculars, 89 Hangar Way, Watsonville, CA 
95076; (800) 676-1343.

To  remove  fingerprints  or  smudges  from  a  lens,  use  photo-
graphic-type  lens  cleaning  fluid  and  lint-free  optical  lens 
cleaning tissue. Do not use household cleaners or eyeglass-
type cleaning cloth or wipes, as they often contain undesirable 
additives  like  silicone,  which  don’t  work  well  on  precision 
optics. Place a few drops of fluid on the tissue (not directly on 
the lens), wipe gently, then remove the fluid with a dry tissue 
or two. Do not “polish” or rub hard when cleaning the lens, as 
this will scratch it. The tissue may leave fibers on the lens, but 
this  is  not  a  problem;  they  can  be  blown  off  with  a  blower 
bulb. 
Never disassemble the telescope or eyepieces to clean opti-
cal surfaces!

10. Specifications

Optical tube: Seamless aluminum
Objective lens diameter: 120mm (4.7")
Objective lens: crown and flint, achromatic, air-spaced, 

diffraction limited
Objective lens coating: fully coated with multi-coatings 
Focal length: 600mm
Focal ratio: f/5
Eyepieces: 25mm and 10mm Plössls, fully coated, 1.25"
Magnification: 24x (with 25mm), 60x (with 10mm)
Focuser: Rack and pinion, accepts 1.25" or 2" accessories
Diagonal: 90° star diagonal, mirror type, 1.25"
Finder scope: 6x magnification, 30mm aperture, achromatic, 

crosshairs
Mount: German-type equatorial
Tripod: Aluminum
Motor drives: Optional 

Summary of Contents for AstroView 120ST EQ

Page 1: ...onsumer Optical Products Since 1975 Customer Support 800 676 1343 E mail support telescope com Corporate Offices 831 763 7000 89 Hangar Way Watsonville CA 95076 instruction Manual Orion AstroView 120S...

Page 2: ...t Toe saver Tripod leg Accessory tray attachment point Accessory tray bracket Accessory tray Leg lock knob Finder scope Finder bracket Focus knob Eyepiece Star diagonal Right Ascension slow motion con...

Page 3: ...have never owned a telescope we are pleased to welcome you to amateur astronomy Take some time to familiarize yourself with the night sky Learn to recognize the patterns of stars in the major con ste...

Page 4: ...the bracket then thread them into the holes in the tray 5 Next tighten the wingnuts at the top of the tripod legs so the legs are securely fastened to the equatorial mount Use the larger wrench and y...

Page 5: ...th the thumbscrews on the diagonal Always loosen the thumbscrews before rotating or removing the diagonal or an eyepiece 16 Install the polar axis finder scope into its housing inside the R A axis of...

Page 6: ...in the horizontal position 5 With one hand on the telescope optical tube loosen the Dec lock lever The telescope should now be able to rotate freely about the Dec axis Loosen the tube ring clamps a fe...

Page 7: ...cope alignment should be checked before every observing session This can easily be done at night before viewing through the telescope Choose any bright star or planet center the object in the telescop...

Page 8: ...ar axis finder scope housed inside the R A axis of the equatorial mount see Figure 4 When properly aligned and used it makes accurate polar alignment quick and easy to do Alignment of the polar finder...

Page 9: ...e it directly into the opening or the light will be too bright and you will also obstruct the view of the polar finder It may be helpful to have a friend hold the flashlight while you look through the...

Page 10: ...set ting circle is scaled in degrees Before you can use the setting circles to locate objects the mount must be accurately polar aligned and the setting cir cles must be calibrated The declination se...

Page 11: ...the counterweight shaft will be oriented somewhere between vertical and horizon tal Figure 9 illustrates how the telescope will look when pointed at the four cardinal directions north south east and...

Page 12: ...lescope has a useful limit of power of about 45x 60x per inch of aperture Claims of higher power by some tele scope manufacturers are a misleading advertising gimmick and should be dismissed Keep in m...

Page 13: ...e too faint to cause any noticeable color distortion How to Find Interesting Celestial Objects To locate celestial objects with your telescope you first need to become reasonably familiar with the nig...

Page 14: ...raphs you see in books and magazines most will look like dim gray smudges Our eyes are not sensitive enough to see color in such faint objects But as you become more experienced and your observing ski...

Page 15: ...king shutter release cable Set the camera s shutter to the B bulb setting Depress the locking shutter release cable and lock it You are now expos ing your first deep sky object While exposing through...

Page 16: ...ngar Way Watsonville CA 95076 800 676 1343 To remove fingerprints or smudges from a lens use photo graphic type lens cleaning fluid and lint free optical lens cleaning tissue Do not use household clea...

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