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INSTRUCTION MANUAL
®
Orion
™
AstroView 120 EQ
#9026 Equatorial Refracting Telescope
Customer Support (800) 676-1343
E-mail: support@telescope.com
Corporate Offices (831) 763-7000
P.O. Box 1815, Santa Cruz, CA 95061
Providing Exceptional Consumer Optical Products Since 1975
IN 124 Rev. C 0900
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Tube rings Objective lens cell Dew cap/ lens shade Right Ascension slow-motion control (not visible) Declination lock lever Finder scope Latitude adjustment T-bolts Finder bracket Counterweight shaft Small counterweight Large counterweight Eyepiece Star diagonal Focus knob Declination slow-motion control Counterweight lock thumbscrews “Toe saver” retaining bolt Right Ascension lock lever Azimuth fine adjustment knobs Polar axis finder scope Tripod leg Accessory tray bracket attachment point Ac
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Congratulations on your purchase of a quality Orion telescope! Your new AstroView 120 EQ Refractor is designed for high-resolution viewing of astronomical objects. With its precision optics and equatorial mount, you’ll be able to locate and enjoy hundreds of fascinating celestial denizens, including the plan- ets, Moon, and a variety of deep-sky galaxies, nebulas, and star clusters. If you have never owned a telescope, we are pleased to welcome you to amateur astronomy. Take some time to familia
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2. Assembly Carefully open all of the boxes in the shipping container. Make sure all the parts listed in Section 1 are present. Save the boxes and packaging material. In the unlikely event that you need to return the telescope, you must use the original packaging. Assembling the telescope for the first time should take about 30 minutes. No tools are needed, other than the ones provid- ed. All bolts should be tightened securely to eliminate flexing and wobbling, but be careful not to over-tighten
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12.To place the finder scope in the finder scope bracket, first unthread the two black nylon screws until the screw ends are flush with the inside diameter of the bracket. Place the O-ring that comes on the base of the bracket over the Setscrew body of the finder scope until it seats into the slot on the Pointer Date circle middle of the finder scope. Slide the eyepiece end (narrow R.A. setting circle end) of the finder scope into the end of the bracket’s cylin- Ring of housing Polar scope der
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a. b. c. d. Figure 5. Proper operation of the equatorial mount requires that the telescope tube be balanced on both the R.A. and Dec. axes. (a) With the R.A. lock lever released, slide the counterweights along the counterweight shaft until they just counterbalance the tube. (b) When you let go with both hands, the tube should not drift up or down. (c) With the Dec. lock lever released, loosen the tube ring lock clamps a few turns and slide the telescope forward or back in the tube rings. (d) Wh
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Right ascension (polar) axis Alignment is easiest to do in daylight hours. First, insert the lowest- Objective Black nylon power (25mm) eyepiece into the star diagonal. Then loosen the lens cell alignment screws R.A. and Dec. lock levers so the telescope can be moved freely. Lock ring Point the main telescope at a discrete object such as the top of a telephone pole or a street sign that is at least a quarter-mile Eyepiece away. Move the telescope so the target object appears in the Spring-loa
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Note: From this point on in your observing session, you should not make any further adjustments to the latitude of the mount, nor should you move the tripod. Doing so will Little Dipper undo the polar alignment. The telescope should be moved (in Ursa Minor) only about its R.A. and Dec. axes. N.C.P. Big Dipper The Polar Axis Finder Scope (in Ursa Major) A nice feature of the AstroView 120 is the polar axis finder scope Polaris housed inside the R.A. axis of the equatorial mount (see Figure 3).
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2. Rotate the date circle until the “0” line on the meridian off- For most accurate polar alignment, you will need to know the set scale lines up with the time meridian indicator mark. approximate longitude of your observing site.This information can The meridian offset scale is printed on the inner circum- be obtained by looking at a local map. Now, you must figure the ference of the date circle, and is labeled “E20” to “W20”. difference between the longitude of your observing site and the The
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Remember, accurate polar alignment is not needed for casu- 4. Loosen the large setscrew just above the R.A. setting circle al visual observing. Most of the time, approximate polar and rotate the R.A. setting circle so the pointer indicates the alignment, as outlined previously, will suffice. R.A. coordinate listed for the bright star in the star atlas. Do not retighten the setscrew when using the R.A. setting cir- Tracking Celestial Objects cles for finding objects; the set screw is only needed
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b. a. c. d. Figure 10. This illustration shows the telescope pointed in the four cardinal directions: (a) north, (b) south, (c) east, (d) west. Note that the tripod and mount have not been moved; only the telescope tube has been moved on the R.A. and Dec. axes. Figure 10 illustrates how the telescope will look when pointed If at all possible, escape the light-polluted city sky and head at the four cardinal directions—north, south, east and west. for darker country skies.You’ll be amazed at how m
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sary, use the R.A. and Dec. slow-motion controls to re-position the able for observing deep-sky objects, as many of them appear object within the field-of-view of the main telescope’s eyepiece. quite big, but faint. If you want to use 2" eyepieces, such as the Orion Optiluxe 2" eyepieces, we recommend that you also Focusing the Telescope purchase a 2" star diagonal for refractors (#8773); this will Practice focusing the telescope in the daytime before using it provide for a comfortable viewing a
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lem that plagues refractor-type telescopes, since light passes You can see a great number and variety of astronomical through both air and glass to form an image. Most astronomical objects with your AstroView 120mm, including: objects emit a spectrum comprised of many different wave- A. The Moon lengths of light, so each wavelength will be bent by a slightly With its rocky, cratered surface, the Moon is one of the easi- different amount when passing through a lens. This results in est and most i
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The famous “Double-Double” in the constellation Lyra and the by using a medium-low power eyepiece (about 25mm); you gorgeous two-color double star Albireo in Cygnus are favorites. can increase the magnification later with a higher-power eye- Defocusing the image of a star slightly can help bring out its color. piece. Then connect the entire camera adapter, with eyepiece inside, to the T-ring. Insert the whole system into the tele- D. Deep-Sky Objects scope’s focuser drawtube and secure firmly wi
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Deep-sky objects are quite faint, and typically require expo- Cleaning the Optics sures on the order of 10 minutes. To hold the camera’s shutter A small amount of dust or a few specks on the glass objective open this long, you will need a locking shutter release cable (main) lens will not affect the performance of the telescope. If dust (#5231). Set the camera’s shutter to the “B” (bulb) setting. builds up, however, simply blow it off with a blower bulb, or lightly Depress the locking shutter re
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One-Year Limited Warranty This Orion AstroView 120 Equatorial refractor is warranted against defects in materials or work- manship 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, pro- vided it is returned postage paid to: Orion Warranty Repair, 89 Hangar Way, Watsonvil
