Orion 8891 Manual Download Page 2

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Parts list

1  Guide scope optical tube assembly
1  Dovetail bracket 
1  Dovetail base 
2   #8-32 x 3/8" flat (countersunk) Phillips head screws, and 2 hex nuts
2   #8-32 x ½" length flat (countersunk) Phillips head screws 
1  Adapter plate
1  Socket head screw, ¼"-20 x 1"
1  Socket head screw, ¼"-20 x 1/2"
1  Parfocal ring, 1.25"
1  Allen wrench, 1.5mm

assembly

The Mini Guide Scope comes fully assembled and mounted in the dovetail 
bracket. Refer to 

Figure 1 to familiarize yourself with the features and parts of the 

guide scope.

Mounting the Mini Guide Scope

The Mini 50mm Guide Scope’s mounting bracket has a dovetail foot that fits the 
Orion dovetail finder scope base included on many Orion telescopes. The guide 
scope also comes with a separate dovetail base (Orion part #7214), with two 
#8-32 x 3/8" flat Phillips-head screws and two hex nuts, for custom installations. 
To mount the Mini 50mm Guide Scope on a dovetail plate such as Orion’s Wide or 
Narrow Universal mounting plates, or similar plates produced under other brands, 
we’ve included an adapter plate that makes it easy. The Mini Guide Scope can 
then be piggybacked on top of your main instrument’s tube rings, or on a side-by-
side saddle plate, for autoguiding. 
On the adapter plate there are three threaded holes. The two outer ones are for 
attaching the dovetail base to the adapter plate, using the two included #8-32 x 
½" length flat (countersunk) Phillips head screws. (These are the longer of the 
four #8-32 screws.) Once the dovetail base is securely attached, you can mount 
the adapter plate onto a dovetail mounting bar or plate by inserting one of the 
supplied 1/4"-20 socket head screws up through an unthreaded hole or slot in the 
dovetail plate and into the ¼"-20 hole in the center of the adapter plate. Tighten 
with a 3/16" Allen wrench (user supplied). We have provided two different socket 
head screws for your convenience, one is ½" long, the other 1" long. Choose the 
one that best fits your mounting bar or plate.

Congratulations on your purchase of the Orion Mini 50mm 
Guide Scope – a “new breed” of simple, compact, and light-
weight guide scope designed for use with the Orion StarShoot 
AutoGuider, Orion StarShoot Planetary Imager & AutoGuider, 
or similar, sensitive small-chip CCD cameras. It’s ideal for 
guiding long-exposure astrophotographs with short to medium 
focal length telescopes up to 1500mm focal length. Its bright, 
wide-field optics serve up lots of potential guide stars on your 
autoguider’s CCD sensor, and it’s small enough to stash in an 
accessory case!

Figure 1. 

The Mini 50mm Guide Scope and included components

Objective 
lens cell

Adjustment 
thumbscrews (x3)

Thumbscrews, 
camera 
attachment

Lock ring

Dovetail foot

Dovetail base

Adapter plate

Hex nuts

#8-32 Screws

Socket head 
screws (x2)

Bracket

O-ring  
(not visible)

1.5mm 
Allen 
wrench

1.25" 
Holder

1.25" Parfocal ring

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