Attaching A Telescope; Balancing A Telescope; Equatorial Mount - Orion ATLAS EQ-G Manual

3. Thread the center support shaft up through the tripod head
and into the bottom of the equatorial mount until tight. Use
the upper knob on the center support shaft to do this. The
equatorial mount should now be firmly connected to the
tripod.
4. Remove the knob and washer from the bottom of the
center support shaft. Slide the tripod support tray up the
bottom of the central support shaft until the three tray
arms are touching the legs of the tripod. The flat side of
the support tray should be facing up. Make sure the "V" of
each tray arm is against a tripod leg. Place the washer on
the center support shaft against the tray, and follow it by
threading the knob all the way up the center support shaft
until it is tight against the tray. The tripod support tray pro-
vides additional stability for the tripod, and holds up to five
1.25" eyepieces and two 2" eyepieces.
5. Loosen the counterweight shaft lock lever and fully extend
the counterweight shaft. Retighten the lock lever.
6. Remove the knurled "toe saver" retaining screw on the
bottom of the counterweight shaft and slide both counter-
weights onto the shaft. Make sure the counterweight lock
knobs are adequately loosened to allow the counterweight
shaft to pass through the hole. Position the counterweights
about halfway up the shaft and tighten the lock knobs.
Replace the toe saver at the end of the bar. The toe saver
prevents the counterweights from falling on your foot if the
lock knobs happen to come loose.
Your Atlas EQ-G mount is now fully assembled and should
resemble Figure 1 except for the hand controller, which will be
installed and explained in Section 7 (Dual-Axis) or Section 8
(GoTo) of this manual.

4. attaching a telescope

The Atlas EQ-G equatorial mount is designed to hold tele-
scope tubes weighing up to approximately 40 lbs. For heavier
telescopes, the mount may not provide sufficient stability for
steady imaging. Any type of telescope can be mounted on the
Atlas EQ-G, including refractors, Newtonian reflectors, and
catadiotropics, provided a set of tube rings is available to cou-
ple the tube to the mount. Orion sells a variety of telescope
tube rings. Please visit our website at OrionTelescopes.com
for details.
Tube ring
attachment screw
Figure 3.
The tube ring mounting plate.
4
1. Attach the tube mounting rings to the tube ring mounting
plate using the screws that come with the tube rings. The
screws should go through the center holes in the ends of
the mounting plate and rethread into the tube rings. Note
that the side of the mounting plate with the central "groove"
will be facing up (Figure 3). Use a small wrench to secure
the tube rings to the mounting plate.
Note: The tube ring mounting plate included with the Atlas
EQ-G includes four optical axis offset adjustment screws;
these are the socket head cap screws located at each cor-
ner of the mounting plate. These adjustment screws will be
explained further in Appendix A. For now, confirm that all four
adjustment screws are sufficiently unthreaded so that the
ends of their threaded shafts are flush with the top surface of
the tube ring mounting plate.
Note: The optical axis offset adjustment screws should be
oriented so that the threaded shaft extends upward through
the top surface of the tube ring mounting plate. If the tube
ring mounting plate arrives with the optical axis offset screws
installed backwards, reverse their orientation before proceed-
ing (Figure 3).
2. Loosen the black mounting plate lock knobs on the top of
the equatorial mount. Place the mounting plate, with the
tube rings attached, in the slot on top of the equatorial
mount. Position the mounting plate so that it is centered in
the slot. Re-tighten the mounting plate lock knobs until the
plate is secure.
3. Open the tube rings and lay the telescope optical tube in
the rings at about the midpoint of the tube's length. Rotate
the tube so that the focuser is at a convenient height for
viewing. Close the tube rings and tighten them.
Note: The Atlas EQ-G mount is very heavy. Alone it weighs 54
lbs. With a large optical tube and counterweights it can easily
weigh over 100 lbs. Keep this in mind when moving the tele-
scope even small distances, and use assistance when need-
ed. It is best to remove the optical tube and counterweights
when moving the mount.
Note: Some telescope optical tubes (specifically Schmidt-
Cassegrains and Maksutov-Cassegrains) have a mounting
plate connected directly to the tube. For these telescopes,
optional tube rings are not required. Simply follow step 2
(above) to connect the telescope to the mount.

5. Balancing a telescope

To ensure smooth movement of a telescope on both axes of
the equatorial mount, it is imperative that the optical tube is
properly balanced. We will first balance the telescope with
respect to the right ascension (R.A.) axis, then the declination
Flat washer
(Dec.) axis.
Lock washer
1. Keeping one hand on the telescope optical tube, loosen
the R.A. lock lever. Make sure the Dec. lock lever is locked,
Optical axis offset
for now. The telescope should now be able to rotate freely
adjustment screws
about the right ascension axis. Rotate it until the counter-
weight shaft is parallel to the ground (i.e., horizontal).