Orion AstroView 100 Instruction Manual

INSTRUCTION MANUAL

IN 159 Rev. A 06/02

Providing Exceptional Consumer Optical Products Since 1975

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Orion

®

AstroView™100

#9861 100mm Refractor Optical Tube Assembly

2

Figure 1.

The AstroView 100.

Finder scope

Finder scope
bracket

Eyepiece

90° star diagonal

Focus wheel

1/4"-20 mounting block

Objective lens

(not visible)

Objective lens cell

Dew shield

Dovetail slot

3

Congratulations on your purchase of an Orion telescope! Your AstroView 100 refractor is designed for

high-resolution viewing of both terrestrial and astronomical objects. Versatile and easy to use, your tele­scope will provide many hours of enjoyment for the whole family.

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

Table of Contents

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

2. Assembly . . . . . . . . . . . . . . . . . . . . . . . . .3

3. Getting Started . . . . . . . . . . . . . . . . . . . .4

4. Using Your Telescope

(Astronomical Observing) . . . . . . . . . . . .5

5. Terrestrial Observing . . . . . . . . . . . . . . . .7

6. Photography . . . . . . . . . . . . . . . . . . . . . .7

7. Collimation . . . . . . . . . . . . . . . . . . . . . . .8

8. Care and Maintenance . . . . . . . . . . . . . .8

9. Specifications . . . . . . . . . . . . . . . . . . . . .9

1. Parts List

Qty. Description

1 Optical tube assembly

1 6x30 achromatic crosshair finder scope

1 Finder scope bracket with O-ring

1 90° Mirror star diagonal (1.25")

1 25mm (24x) Sirius Plössl eyepiece (1.25")

1 10mm (60x) Sirius Plössl eyepiece (1.25")

1 Objective lens dust cover

1 Collimation tool

2. Assembly

Carefully open the box and make certain all the parts listed in
the parts list are present. Save the box and packaging materi­al. In the unlikely event that you need to return the telescope,
you must use the original packaging. Refer to Figure 1 during
assembly.

Installing the Finder Scope

To place the finder scope in the finder scope bracket, first
unthread the two black nylon thumbscrews 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 eyepiece end (narrow end) of

the finder scope into the end of the bracket’s cylinder opposite
the adjustment screws while pulling the chrome, spring­loaded tensioner on the bracket with your fingers (Figure 2b.)
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.

Insert the base of the finder scope bracket into the dovetail
slot on the top of the focuser housing. Lock the bracket into
position by tightening the knurled thumbscrew on the dovetail
slot.

Finder scope

Finder scope
bracket

Nylon
thumbscrews

Focusing lock ring

Figure 2b.

Pull back on the
tensioner and slide
the finder scope
into its bracket until
the O-ring is
seated in the
bracket ring

Figure 2a. The 6x26 Correct-Image finder scope

Tensioner

4

Inserting the Diagonal and Eyepiece

Remove the cover cap on the end of the focuser. Insert the
chrome barrel of the star diagonal into the focuser and secure
with the thumbscrews on the 1.25" adapter (Figure 3). Insert
the 25mm Sirius Plössl 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.

Attaching the AstroView 100 to a Tripod or Mount

The AstroView 100 can be attached to a tripod or mount by
the use of its 1/4"-20 mounting block, or by using optional tube
rings available from Orion. The 1/4"-20 shaft of a sturdy cam­era tripod will thread into the hole in the mounting block on the
underside of the optical tube. If you are using tube rings, you
should first attach them to your telescope mount and then lay
the optical tube in the tube rings.

3. Getting Started

Focusing the Telescope

Practice focusing the telescope in the daytime before using it
for the first time at night. Make sure the focus lock thumbscrew
is loosened before focusing (Figure 3). Turn the focus wheel
until the focuser drawtube is near the center of its adjustment
range. Point the telescope at a distant subject and center it in
the field of view. Now, slowly rotate the focus knob until the
object comes into sharp focus. Go a little bit beyond sharp
focus until the image just starts to blur again, then reverse the
rotation of the knob, just to make sure you hit the exact focus
point. The telescope can only focus on objects at least 50 to
100 feet away.

Viewing with Eyeglasses

If you wear eyeglasses, you may be able to keep them on
while you observe, if the eyepiece has enough “eye relief” to
allow you to see the whole field of view. You can try this by
looking through the eyepiece first with your glasses on and
then with them off, to see if the glasses restrict the view to
only a portion of the full field. If they do, you can easily
observe with your glasses off by just refocusing the telescope
the needed amount. If you suffer from severe astigmatism,
however, you may find images noticeably sharper with your
glasses on.

Aligning the Finder Scope

The finder scope has a wide field of view to facilitate locating
of objects for subsequent viewing through the main telescope,
which has a much narrower field of view. The finder scope and
the main telescope must be aligned so they point to exactly
the same spot in the sky.

Alignment is easiest to do in daylight hours. With the eyepiece
inserted in the star diagonal, point the main telescope at an
object such as the top of a telephone pole or a street sign that
is at least a quarter-mile away. Move the telescope so the tar­get object appears in the very center of the field of view when
you look into the eyepiece. Now tighten the mount (or tripod)
so that the optical tube will remain in place.

Now look through the finder scope. Is the object centered in
the finder scope’s field of view, i.e., on the crosshairs? If not,
hopefully it will be visible somewhere in the field of view, so
that only fine adjustment of the finder scope alignment screws
will be needed to center it on the crosshairs. Otherwise you’ll
have to make coarser adjustments to the two black nylon
alignment screws to redirect the aim of the finder scope.

Note that the image seen through the finder scope appears
upside down (rotated 180°). This is normal for astronomical
finder scopes. The image through the telescope will be invert­ed left-to-right, which is normal for refractor telescopes that
utilize a star diagonal.

Once the target object is centered on the crosshairs of the
finder scope, look again in the telescope’s eyepiece and see if
it is still centered there as well. If it isn’t, repeat the entire
process, making sure not to move the telescope while adjust­ing the alignment of the finder scope.

When the target object is centered on the crosshairs of the
finder scope and in the telescope’s eyepiece, the finder scope
is now aligned and ready to be used for an observing session.
The finder scope and bracket can be removed from the dove­tail for storage, and then reinstalled without significantly
changing the finder scope’s alignment.

The finder scope 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 telescope eyepiece, and then
adjust the finder scope’s alignment screws until the star or
planet is also centered on the finder’s crosshairs. The finder
scope is an invaluable tool for finding objects in the night sky.

Figure 3. The Focuser of the AstroView 100

2" adapter

1.25" adapter

90° star diagonal

Focus lock thumbscrew

Eyepiece

Camera T-ring

attachment threads