The Losmandy GM8 is a well made mount that is fairly portable, but can still hold a decent amount of weight. Rated at a 30 pound payload capacity it is a perfect fit for almost every 4" refractor, most 6" mak-newts, and even some 5" refractors.
With standard periodic error correction it also makes a nice photographic platform.
SPECIFICATION: R.A. / DEC. AXIS
- All machined aluminum and stainless steel, black anodized
- All stainless steel hardware.
- One 2.100" diameter needle thrust bearing.
- One 2.000" diameter needle thrust bearing.
- Two 1.500" diameter needle bearings.
- 2.812" diameter, 7075 aluminum worm gear, 180 tooth.
- Dual supported, ball bearing housed stainless steel worm-heat treated and ground.
- Variable slip clutch, both axes. One knob design.
- 1.250" diameter aluminum shafts.
- Fully locking, unique tangent arm design altitude adjustment, 0-64 degrees, large knob for easy alignment.
- Laser engraved latitude scale in 2 degree increments.
- Single knob azimuth control, bi-directional +/- 8.5 degrees.
- 3.500" diameter laser engraved setting circles 6 minute R.A. / 2 degrees DEC. R.A. circle engraved for Northern and Southern Hemisphere.
- Porter slip ring design.
- 160 oz/in stepper motor, 1.0 arc sec. step.
- Its dovetail saddle accepts both Losmandy D-plate and Vixen-style dovetails, allowing for the interchanging of any tube assembly. Its range of fore and aft adjustment reduces the need for declination weights.
- Removable stainless steel weight shaft w/safety knob.
- 7 lb counterweight.
- 11 lb and 21 lb. extra counterweights available.
- Through the axis polar scope, works in Northern and Southern hemisphere. Polar scope optional.
- Instrument weight capacity 30 lbs.
- Equatorial head weight 21 lbs.
- All machined aluminum, black anodized.
- Tripod height, adjustable from 27" - 43"
- Fold-up tripod design for easy transporting.
- Tripod weight 15 lbs.
- Diamond push button pattern.
- R.A. and DEC. reversing switches.
- Three guiding rates; 30%, 50% and 2x sidereal rate.
- Three setting rates; 4x, 8x, 16x sidereal rate and super fast 32x HST (high speed transfer).
- Quartz tracking rates: sidereal, solar, lunar, king.
- Periodic Error Correction (PEC).
- Programmable DEC. Backlash Compensation (TVC).
- Control panel dimmer.
- Accepts auto-guider systems.
- Northern and Southern Hemisphere operation.
- 12 volt DC - 500ma power use
- Tiltable control panel for easy access.
- Small hand control box for comfortable use.
All heights are to top of tripod. Add 9" @ 34 degrees to center of Dec.-R.A. junction. Add 6" from Dec.-R.A. junction to top of saddle.
Losmandy Gemini Servo System
Precision made in the U.S.A by Hollywood General Machining with software developed in Germany the Gemini, servo based, GOTO system, delivers a high torque servo based computerized drive system never before seen in high quality amateur telescope mountings. Gemini allows both stand alone and PC based control of Losmandy's G8, G-11 and HGM200 series mounts.
The GOTO control electronics have typical Losmandy hallmarks of being fully machined, anodized and brushed, with beautifully radiused edges that look like part of a Losmandy system, rather than a third party bolt on. The new electronics control system case has been designed to fit on the existing control case mounting tabs on all Losmandy G-8, G-11 and HGM200 tripods.
The feature set is comprehensive, making the system ideal for both casual observing and serious research. The system has been thoroughly tested in both Northern and Southern Hemispheres, and has been designed for precise and dependable use. First production runs are expected to be available by summer 2000 (Northern winter).
Gemini System Features
DC Servo Motors
Being DC servo based the new drive system has high torque through its entire range of tracking and slewing speeds.
Other features include:
- The electronic is capable of a slewing speed of more than 1450x sidereal rate (6 degrees per second),
- 800x is recommended for the HGM200, G-11
- Goto and Manual Slewing speeds can be adjusted separately.
- Smooth ramping up and down of slew to reduce drive wear and tear.
- Centering Speeds from 1x up to 255x,
- Guiding Speed from 0.2x to 0.8x
While tracking, the step frequency is approximately 1/10th of an arc second giving much smoother tracking than existing stepper motor based systems. An adaptive King tracking rate that accounts for atmospheric refraction with differing object elevations is also now available. Other features are:
- Sidereal Rate
- Solar Rate
- Averaged Lunar Rate
- Terrestrial mode (no tracking)
- Adaptive (DEC dependent) or static King rate tracking
- Permanent Periodic Error Correction (PEC) and backlash compensation (TVC)
Hand controller (4+1 keys)
Used for both Telescope Control and Menu control
- Visual mode: centering and slewing speed
- Photographic mode: guiding and centering (stepping up from 1/8 to full centering speed)
- All speed mode
- Speeding up by pressing the opposite key while moving
16 Character dimmable red LED display
The display module can be adjusted in brightness and allows for speeding up or repetition of displayed object data by a single key press.
An optional DeLuxe Hand controller will also be available which can display all information available on the main display
Separate Autoguider Connector
- Compatible to hand controller connector, but only for guiding speed
- Control pin for camera shutter connected to alarm timer
Mount Shaft Encoders are supported
Use of existing optical encoders allows for manual movements of the mount with positional data limited only by encoder resolution
- Encoder resolution and direction adjustable for DEC and RA,
- Ultra high precision pointing (Motor encoder based) is returned by a simple realignment after a manual move.
- GuideTo function allows for manual movement or electrical slewing to the selected database object.
Database objects are stored with coordinates, type, size, magnitude. Objects are precessed to the current date, corrected for refraction.
- All objects of the Revised NGC/IC catalog are contained, by courtesy of Wolfgang Steinicke, the NGC/IC project.
- Messier and Sharpless 2 catalog.
- Planets, Moon, Sun
- Bright star list with common names
- SAO, WDS, GPN, LDN, LBN
- Alignment at bright star or any database object, east or west of the meridian.
- Identify function, selectable for catalog, object type, magnitude.
Permanent Setup and Modeling
- 1-star alignment for polar aligned mount
- 3-star alignment for correcting GoTo positions for polar misalignment
- 4-star alignment models some residual errors
- Switch off time and position are saved for warm restarting the system
- Slewing to an object from the internal databases
- Slewing to manually entered RA/DEC coordinates
- Slewing to a bookmark set by the user.
- Slewing to one of 10 objects found by Identify.
- Check if object is above the horizon.
- Meridian flip if necessary.
- Adjustable East/West Safety Limits.
Serial Port Communication
Partial emulation of the LX200 protocol for communication with planetarium software. Tested O.K. with SkyMap, Guide 7.0 and TheSky.
- Slewing to objects, reporting position back, setting date/time/location/time zone from the PC
- After power up and initial alignment, telescope control can be done by the planetarium software.
- Communication with XEphem planetarium software, driver available.
- Object Search mode.
Real Time Clock
Real Time Clock w/battery backup, running UTC
Time/Date display showing
- Julian Date
- Sidereal Time
- Civil Time
- Local Mean Sidereal Time.
- Alarm timer, also controlling the camera shutter output pin.
Battery backup of all SRAM data
All Setup data for motors, mount and encoders is permanmently stored
- Geographic Location and Timezone
- PEC data
- Last used alignment star
- Display brightness
- Modeling parameters
- Last switch-off time and position pointed to.
- Observing Log containing objects observed, time stamps.
Analog inputs and digital input/output ports
- Ground and +5V connector
Different usage possibilities with support in subsequent software releases