Instruction Manual: Losmandy G-11 Mount Part 1

The Losmandy G-11 Mount

Checking the parts

Depending on which accessories you ordered, your G-11 mount was shipped in four or more boxes. The contents of each box are as follows:

• Equatorial Mount

• Adjustable Tripod Legs, Leg Clamps, Counterweight Shaft

• Tripod Center Column, Digital Drive Box, Hand Control, Cables, Mounting Bolts, Allen Wrench, Counterweight Safety Screw

• 21 lb. Weight, Locking Bolt

Remove all the parts from their respective boxes and place them on a flat, clear work area. A large floor space is ideal. When setting up your Losmandy G-11, you must start with the tripod and work from there. To insure proper assembly, each task must be performed in the specific order as defined by these instructions.



Assembling the tripod

Remove the legs, leg clamps and weight shaft from the box. Place one leg clamp on the end of each tripod leg, making sure the screw on the side of each leg clamp lines up with the hole on the tripod leg. These clamps will remain on the legs and will not be taken off. Slide the legs onto the center column and lock in place by turning each knob on the leg clamps. The tripod is now ready for the equatorial mount.

Attaching the equatorial mount

After the tripod is set up, you are ready to attach the equatorial mount. This is the platform to which the telescope attaches and allows you to direct it anywhere in the sky. The mount is also adjustable so you can orient the axis of rotation to make it parallel with the Earth’s axis of rotation (see the section on Polar Alignment). To attach the equatorial mount to the tripod:

1. Insert the base of the equatorial mount into the top of the central column.

2. Rotate the equatorial mount on the central column until the holes in the mount line up with those in the central column.

3. Insert the three screws provided through the holes in the central column and into the equatorial mount.

4. Tighten the screws to hold the equatorial mount in place.

There are three possible orientations of the equatorial mount which allow you to select the most convenient location of the electronic console.

 

Attaching the counterweight bar

To properly balance the telescope, the mount comes with a counterweight bar and counterweight. To install the counterweight bar:

1. Locate the opening in the equatorial mount on the DEC axis. It is opposite the telescope mounting platform.

2. Thread the counterweight bar into the opening until tight.

Once the bar is securely in place you are ready to attach the counterweight(s).

 

Attaching the counterweight

The Losmandy G-11 comes standard with one 21 pound counterweight.

To install the counterweight:

1. Orient the mount so that the counterweight bar points toward the ground.

2. Remove the counterweight safety thumbscrew and washer on the end of the counterweight bar (opposite the end that attaches to the mount).

3. Loosen the locking bolt on the side of the counterweight.

4. Slide the counterweight onto the shaft.

5. Tighten the locking bolt on the side of the weight to hold it in place.

6. Repeat this process if using a second optional counterweight.

7. Replace the counterweight safety thumbscrew and washer.

 

Attaching the telescope to the mount

The telescope attaches to the mount via a dovetail bar bolted to the bottom of the telescope. Before you attach the optical tube, make sure that the declination and right ascension clutch knobs are tight. This will ensure that the mount does not move suddenly while attaching the telescope. To mount the telescope tube:

1. Loosen the knob on the side of the telescope mounting platform. This allows you to slide the dovetail bracket of the telescope onto the mount.

2. Slide the dovetail bar of the telescope tube into the mounting platform of the mount. Slide the telescope so that the back of the dovetail bar is almost flush with the back of the mounting platform.

3. Tighten the knob on the side of the mounting platform to hold the telescope in place.

Installing the polar alignment finder

To aid in polar aligning the mount, your Losmandy G-11 accepts an optional Polar Axis Finder which fits directly into the polar axis. To install:

1. Remove the polar axis end covers by rotating counterclockwise.

2. Insert the objective end of the Polar Axis Finder into the opening on the lower end of the polar axis.

3. Rotate the slip ring on the Polar Axis Finder until snug. The Polar Axis Finder should still rotate without play.

Installing the polar alignment illuminator

If you look through the Polar Axis Finder in the daytime the reticle is clearly visible. To see the reticle at night, however, you need to install the illuminator.

1. Remove the plastic battery holder from the battery pouch.

2. Insert two AA batteries into the plastic battery holder.

3. Attach the cable with the 9-volt style terminal to the battery holder.

4. Place the battery holder back into the battery pouch.

5. Thread the LED illuminator into the hole on the side of the polar axis finder.

6. Insert the connector on the wire which attaches to the LED into the wire connector from the battery housing. The LED will illuminate.

The Polar Axis Finder is now installed and ready to use. To turn the LED off, unplug the wires that connect the LED to the battery housing. 

Moving the telescope in R.A. and DEC

Once the telescope is set up, you will need to point it at various locations to observe different objects. Unlike other systems, the Losmandy mounts have a clutch system. To make rough adjustments, loosen the R.A. and DEC clutch knobs slightly and move the telescope in the desired direction. The R.A. clutch knob is near the Polar Axis Finder while the DEC clutch knob is at the top of the counterweight bar. How tight should the clutch knobs be? You set the clutch knobs to the friction you like. When you want to move the telescope, all you do is grab the telescope and move it to its new position.

For fine adjustments, use the fast-set function on the hand control box. For more information please see the section on Using the Drive.

Balancing the telescope on R.A.

To eliminate undue stress on the mount, the telescope should be properly balanced around the polar axis. Proper balancing is crucial for accurate tracking. To balance the mount:

1. Verify that the telescope securing knob on the telescope mounting platform is tight.

2. Loosen the R.A. clutch knob and position the telescope off to one side of the mount. The counterweight bar will extend horizontally on the opposite side of the mount.

3. Release the telescope to see which way the telescope may drift as a result of an imbalance.

4. Loosen the locking bolt on the side of the counterweight so it can slide along the length of the counterweight bar.

5. Move the counterweight to a point where it balances the telescope. The telescope should remain stationary when the R.A clutch knob is loose.

6. Tighten the locking bolt on the counterweight to hold it in place.

While the above instructions describe a perfect balance arrangement, there should be slight imbalance to ensure the best possible tracking. When the scope is on the west side of the mount the counterweight should be slightly imbalanced to the counterweight bar side. And when the tube is on the east side of the mount there should be a slight imbalance toward the telescope side. This is done so that the worm gear is pushing against the slight load. THE AMOUNT OF THE IMBALANCE IS VERY SLIGHT. When taking astro-photographs, this balance process can be done for the specific aim of the telescope to further optimize tracking accuracy.

Balancing the mount in DEC

Although the telescope does not track in declination, the telescope should also be balanced in this axis to prevent any sudden motions when the DEC clutch knob is loose. To balance the telescope in DEC:

1. Loosen the R.A. clutch knob and rotate the telescope so that it is on one side of the mount (as described in the previous section on Balancing the Mount in R.A.).

2. Tighten the R.A. clutch knob to hold the telescope in place.

3. Loosen the DEC clutch knob and rotate the telescope until the tube is parallel to the ground.

4. Release the tube to see which way it rotates around the declination axis.

DO NOT LET GO OF THE TELESCOPE TUBE COMPLETELY!

5. Slightly loosen the knob that holds the telescope to the mounting platform and slide the telescope either forward or backward until it remains stationary when the DEC clutch is loose.

DO NOT LET GO OF THE TELESCOPE TUBE WHILE THE KNOB ON THE MOUNTING PLATFORM IS LOOSE.

6. Tighten the knob on the telescope mounting platform to hold the telescope in place.

Like R.A. balance, these are general balance instructions and will reduce undue stress on the mount. When taking astrophotographs, this balance process should be done for the specific area at which the telescope is pointing.

 

Go to Part 2 of this Instruction Manual.