Orion AstroView 120 EQ, 9026 Instruction Manual

IN 124 Rev. C 0900

Providing Exceptional Consumer Optical Products Since 1975

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INSTRUCTION MANUAL

Orion

®

AstroView™ 120 EQ

#9026 Equatorial Refracting Telescope

2

Tube rings
Objective lens cell
Dew cap/ lens shade

Right Ascension
slow-motion control
(not visible)
Declination lock lever
Latitude adjustment T-bolts

Counterweight shaft
Small counterweight
Large counterweight

Counterweight lock thumbscrews
“Toe saver” retaining bolt

Azimuth fine adjustment knobs

Tripod leg

Accessory tray bracket
attachment point
Accessory tray bracket
Accessory tray

Leg lock knob

Finder scope

Finder bracket

Eyepiece

Star diagonal

Focus knob

Declination slow-motion control

Right Ascension lock lever

Polar axis finder scope

Figure 1. The AstroView 120 EQ Refractor

3

1. Parts List

Qty. Description
1 Optical tube assembly
1 German-type equatorial mount
1 Large counterweight
1 Small counterweight
1 Counterweight shaft
3 Tripod Legs with mounting hardware
1 Accessory tray with mounting hardware
1 Accessory tray bracket
2 Slow-motion control cables
1 Polar axis finder scope
1 Plastic cover for polar axis finder scope
2 Optical tube mounting rings
1 6x30 achromatic crosshair finder scope
1 Finder scope bracket with O-ring

1 Mirror star diagonal (1.25")
1 25mm (40x) Plössl eyepiece (1.25")
1 10mm (100x) Plössl eyepiece (1.25")
1 Objective lens dust cap
1 Lens Shade
1 Lens Shade dust cap
4 Assembly Tools (2 wrenches, Phillips screwdriver,

flat-head screwdriver key)

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 plan­ets, Moon, and a variety of deep-sky galaxies, nebulas, and star clusters.

If you hav e never owned a telescope, w e are pleased to w elcome y ou to amateur astronomy.Take some
time to familiarize yourself with the night sky. Learn to recognize the patter ns of stars in the major con­stellations; a star wheel, or planisphere, available from Orion or from your local telescope shop, will
greatly help.With a little practice, a little patience, and a reasonably dark sky away from city lights, you’ll
find your telescope to be a never-ending source of wonder, exploration, and relaxation.

These instructions will help you set up, properly use and care for your telescope.Please read them over
thoroughly before getting started.

Table of Contents

1. Parts List............................................................................................................................... 3

2. Assembly.............................................................................................................................. 4

3. Balancing the Telescope.......................................................................................................5

4. Aligning the Finder Scope.................................................................................................... 6

5. Setting Up and Using the Equatorial Mount ......................................................................... 7

6. Using Your T elescope–Astronomical Observing................................................................... 11

7. Astrophotography.................................................................................................................. 14

8. Terrestrial Viewing................................................................................................................. 15

9. Care and Maintenance......................................................................................................... 15

10. Specifications........................................................................................................................ 15

WARNING: Never look directly at the Sun

through your telescope or its finder scope—
even for an instant—without a professionally
made solar filter that completely covers the
front of the instrument, or permanent eye
damage could result.Young children should use
this telescope only with adult supervision.

4

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 bo xes
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 provid­ed. All bolts should be tightened securely to eliminate flexing
and wobbling, but be careful not to ov er-tighten or the threads
may strip.Refer to Figure 1 during the assembly process.

During assembly (and anytime, for that matter), DO NOT
touch the surfaces of the telescope objective lens or the lens­es of the finder scope or eyepieces with your fingers. The
optical surfaces have delicate coatings on them that can eas­ily be damaged if touched inappropriately. NEVER remove
any lens assembly from its housing for any reason, or the
product warranty and return policy will be voided.

1. Lay the equatorial mount on its side.Attach the tripod legs
one at a time to the mount using the bolts installed in the
tops of the tripod legs. Remove the bolt from the leg, line
up the holes in the top of the leg with the holes in the base
of the mount, and reinstall the bolt so it passes through
the leg and the mount. Tighten the wingnuts only finger­tight, for now. Note that the accessory tray bracket
attachment point on each leg should face inward.

2. Tighten the leg lock knobs at the base of the tripod legs.
For now, keep the legs at their shortest (fully retracted)
length; you can extend them to a more desirable length
later, after the scope is completely assembled.

3. With the tripod legs now attached to the equatorial mount,
stand the tripod upright (be careful!) and spread the legs
apart enough to connect each end of the accessory tray
bracket to the attachment point on each leg. Use the bolt
that comes installed in each attachment point to do this.
First remove the bolt using the supplied screwdriver, then
line up one of the ends of the bracket with the attachment
point and reinstall the bolt. Make sure the smooth side of
the accessory tray bracket faces up.

4. Now , with the accessory tray br acket attached, spread the
tripod legs apart as far as they will go, until the bracket is
taut. Attach the accessor y tray to the brackets with the
three wingnut-head bolts already installed in the tray.Push
the bolts up through the holes in 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 your fingers to do this.

6. Orient the equatorial mount as it appears in Figure 1, at a
latitude of about 40°, i.e., so the pointer next to the latitude
scale (located directly above the Orion logo on one side of
the mount) is pointing to the line at “40.”To do this, loosen
one of the latitude adjusting T-bolts and then tighten the
other latitude adjusting T-bolt until the pointer and the “40”
line up (Figure 2).The declination (Dec.) and right ascen­sion (R.A.) axes many need re-positioning (rotation) as

well.Be sure to loosen the RA and Dec.lock le vers before
doing this. Retighten them once the equatorial mount is
properly oriented.

7. Thread the counterweight shaft in to the equatorial mount
at the base of the declination axis until tight. Make sure
the casting at the top of the bar is threaded clockwise as
far as it will go before attaching the shaft.

8. Remove the knurled “toe saver” retaining bolt on the bot­tom of the counterweight shaft and slide both
counterweights onto the shaft. Make sure the counter­weight lock thumbscrews are adequately loosened so the
metal pin inside the counterweight is recessed enough to
allow the counterweight shaft to pass through the hole.
Position the counterweights about halfway up the shaft
and tighten the lock thumbscrews. Replace the toe saver
on the end of the bar.It prevents the counterweights from
falling on your foot if the lock thumbscrews happen to
come loose.

9. Attach the two tube rings to the equatorial head using the
bolts that come installed in the rings.Remove the bolts , then
push them, with the washers still attached, up through the
holes in the tube ring mounting plate (on the top of the equa­torial mount) and rethread them into the bottom of the tube
rings. Tighten the bolts securely with the smaller wrench.
Open the tube rings by loosening the knurled ring clamps.

10.Lay the telescope optical tube in the tube rings at about the
midpoint of the tube’s length. Rotate the tube in the rings
so the focus knobs are on the underside of the telescope.
Close the rings over the tube and tighten the knurled ring
clamps finger-tight to secure the telescope in position.

11. Now attach the two slow-motion cables to the R.A. and
Dec.worm gear shafts of the equatorial mount by position­ing the setscrew on the end of the cable over the indented
slot on the worm gear shaft.Then tighten the setscrew.

Figure 2. To adjust the latitude angle of the equatorial
mount, loosen one of the two latitude adjustment T-bolts,
then tighten the other.

5

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
body of the finder scope until it seats into the slot on the
middle of the finder scope.Slide the ey epiece end (narrow
end) of the finder scope into the end of the bracket’s cylin­der that does not have the adjustment screws while pulling
the chrome, spring-loaded tensioner on the bracket with
your fingers. Push the finder scope through the bracket
until the O-ring seats just inside the front opening of the
bracket cylinder. Now, release the tensioner and tighten
the two black nylon screws a couple of turns each to
secure the finder scope in place.

13. Inser t the base of the finder scope bracket into the dove­tail slot on the top of the focuser housing.Lock the br ac k et
into position by tightening the knurled setscrew on the
dovetail slot.

14.Remove the cover cap on the end of the f ocuser .Insert the
chrome barrel of the star diagonal into the focuser and
secure with the thumbscrew on the drawtube.

15.Then insert an eyepiece into the star diagonal and secure
it in place with the thumbscrews on the diagonal. (Always
loosen the thumbscrews before rotating or removing the
diagonal or an eyepiece.)

16. Remove the objective lens dust cover and slide the metal
lens shade over the front of the objective lens cell. The
end of the lens shade with the 3 felt tabs should seat
directly on the lens cell.

17. Install the polar axis finder scope into its housing inside
the R.A. axis of the equatorial mount (Figure 3). First
loosen the three setscrews on the housing, which is locat­ed at the rear of the R.A. axis. Remove the rubber O-ring
from the finder and seat it in the groove that is just inside
the housing’s opening. Insert the front end of the polar
finder (the end without the eyeguard) into the housing and
through the O-ring so only about 1" of the polar finder
extends from the back of the housing. Do this slowly and
with a twisting motion to prevent the O-ring from becom­ing unseated. If it does become unseated, you can
remove the entire housing from the mount to locate the O­ring and reseat it. This is done by rotating the entire
housing counterclockwise. Once the polar axis finder
scope is in the housing, tighten the three setscrews on the
housing. These setscrews will be used later to align the
finder with the mount’s R.A.axis.Now thread the housing
assembly back into the mount (Figure 4).

The AstroView 120 is now assembled and should appear as
pictured in Figure 1.

3. Balancing the Telescope

To ensure smooth movement of the telescope on both ax es of
the equatorial mount, it is imperative that the optical tube is
properly balanced. We will first balance the telescope with
respect to the R.A. axis, then the Dec. axis.

1. Keeping one hand on the telescope optical tube, loosen
the R.A.lock le ve r .Make sure the Dec.lock lev er is lock ed,
for now.The telescope should now be able to rotate freely
about the R.A. axis. Rotate it until the counterweight shaft
is parallel to the ground (i.e., horizontal).

Setscrew

Pointer

R.A. setting circle

Polar scope

alignment screw

Polar axis

finder scope

Figure 3. The polar axis finder scope is shown here
installed in the right ascension (R.A.) housing of the mount.

Date circle

Ring of housing
containing time
meridian indicator
mark

Figure 4. You may find it easier to install the polar axis
finder scope by unthreading the rear part of the R.A.
housing, inserting the finder in it, then rethreading the
assembly back on the mount.