GM-8 Equatorial mount with tripod and dual axis drive

THIS PRODUCT HAS BEEN DISCONTINUED.  THIS IS HERE FOR INFORMATIONAL PURPOSES ONLY.

The Losmandy GM-8 mount is a well-made, high-precision German equatorial mount that is very portable, but can still hold a respectable payload. It is rated at a 30 pound payload capacity, making it an excellent choice for almost every 4" refractor, most 6" Maksutov-Cassegrains and Maksutov-Newtonians, and even some 5" refractors. It comes standard with a dual axis drive system whose built-in drive corrector includes periodic error correction, making it a nice photographic platform for the serious astrophotographer.

The Losmandy GM-8 equatorial head:

All parts are machined from stainless steel or aluminum. All aluminum parts are black anodized. All hardware is stainless steel for rust-free long life.

Bearings include one 2.100" diameter needle thrust bearing, one 2.000" diameter needle thrust bearing, and two 1.500" diameter needle bearings. Right ascension and declination shafts are precision-machined of 1.250" diameter aluminum. The 180 tooth main drive gear is machined of 2.812" diameter 7075 aluminum. The heat-treated and ground stainless steel worm is in a dual supported ball bearing housing. There is a one-knob design variable slip clutch on each axis. The drive uses a 160 oz/in stepper motor, with 1.0 arc second steps.

The unique fully-locking tangent arm design altitude adjustment allows use over a 0-64 degree latitude range. There is a single large adjustment knob for easy alignment. The latitude scale is laser engraved in 2 degree increments. The two-knob azimuth control provides a +/- 8.5 degree adjustment range and positive locking.
3.500" diameter laser engraved setting circles are marked in 6 minute increments in right ascension and 2 degree increments in declination. The right ascension circle is engraved for both Northern and Southern Hemisphere use. The r. a. circle is a Porter slip ring design, so that when the mount is moved manually, or driven electronically, the r. a. circle follows the stars with no need to be reset periodically.

A dovetail saddle that can accept both Losmandy D-plate and Vixen-style OTA dovetails allows for the fast interchanging of tube assemblies. Its range of fore and aft adjustment reduces the need for declination weights. The stainless steel counter weight shaft is removable and has a safety knob. The payload capacity is 30 lbs. The equatorial head weighs 21 lbs., exclusive of counterweight(s). The mount comes with one 7 lb. counterweight standard. Additional 11 lb. and 21 lb. counterweights are available to balance heavy payloads.

An optional illuminated through-the-axis polar alignment scope works in both Northern and Southern Hemispheres.

The Losmandy GM-8 tripod:

The tripod is made of all machined aluminum, black anodized. Fold-up design for easy transporting. The tripod height is adjustable from 27" to 43". All heights are to the top of the tripod. Add 15" (at a latitude of 34 degrees) to account for the distance from the top of the tripod to the top of the saddle. This total will give you the distance from the ground to the underside of the telescope optical tube. The tripod weighs 15 lbs.

The Losmandy GM-8 dual-axis electronics:

The hand control box is small for comfortable use. The directional buttons on the hand control are in an intuitive diamond push button pattern. There are right ascension and declination reversing switches. Additional features include a control panel dimmer and selectable Northern and Southern Hemisphere operation, and an input for a CCD auto-guider. The control panel can be tilted for easy access. 

There are three guiding rates - 30%, 50%, and 2x the sidereal rate. There are three setting (centering) rates - 4x, 8x, and 16x the sidereal rate, and a super fast 32x HST (high speed transfer). There are four quartz-locked tracking rates - sidereal, solar, lunar, and a King rate to compensate for atmospheric refraction when observing or imaging near the horizon. There is built-in Periodic Error Correction (PEC) for astrophotographic guiding, and programmable declination backlash compensation (TVC).

The drive is a 12 volt DC design. Adapters are provided to plug the mount into a rechargeable 12 volt battery. An optional adapter lets you plug it into an AC outlet. Current drain during operation is 500ma.