Losmandy Telescope Mounts

The Gemini system is now shipping with level 4 software!

The system can be ordered with all new Losmandy mounts, or easily retrofitted by users who already own a G-8, G-11 or HGM200 mount. The new Gemini system simply replaces the existing stepper drive motors and electronics, with hex keys plus a small pair of pliers being the only tools required to upgrade the drive.

The Gemini system has many features designed to quickly and accurately point the telescope to an object, then track it with even higher precision than the previous digital stepper drive used by Losmandy.

The choice of servo motors gives two main advantages over stepper motor based systems.

Servo motors run with a continuous smooth rotation, rather than discreet steps as with stepper motors. They also have very high torque, even at high slewing speeds. As a result the Gemini system can deliver up to *10 degrees per second slewing rates, yet still retain motor positional information of around 1/10th of an arc second. (*maximum speed with the G-8. Expect approximately 6 degrees per second with G-11 and HGM200 models ).

The Gemini system will also accept inputs from optional shaft encoders (the same as used in Losmandy digital setting circles), which allow the telescope to be positioned by hand, yet still retain pointing information. Hand movement of the telescope will drop positional accuracy to that of the shaft encoders, but this can be easily refined using a quick synchronization or alignment position from a nearby object, which will return the system to full motor encoder accuracy.

Gemini can be used as a stand alone system in the field. It can be powered by any 1500+mA, 12-18 Volt DC source. No personal computer is required. A user brightness adjustable LED display allows navigation through all internal databases for field use without a PC. The following databases comprising about 41,000 objects are built into the Gemini system, more than enough to keep even the most avid observer busy for some time!

• Messier catalogue                        (110 objects)
• NGC revised NGC                         (7840 objects
• IC revised IC                                (5386 objects)
• Sh2 Sharpless 2                           (313 objects)
• Bright Stars                                  (167 Objects)
• SAO Stars                                    (17635 Objects)

(The above database links will take you to ASCII text listings of each catalogue)

• Very High Precision pointing to less than 1 arc minute
• Object search mode with user definable search radius
• Sidereal, Solar Lunar and King tracking rates
• User brightness adjustable LED display
• Up to 256 alignment stars permitted either side of the meridian
• Menus are accessed by the standard Losmandy 4 button hand paddle 
• A deluxe hand paddle that repeats the Main panel display information
• RS232 serial port control by a PC using software such as The Sky, Guide 7.0 or Palm Planetarium
• T-Point (Software Bisque) Compatible
• Internal real time clock that displays, UTC, Local Mean Time an Sidereal Time
• Up to 10 degrees per second slewing (G-8)
• User definable Guiding, Centering Slewing and GOTO speeds 
• Permanent Periodic error Correction
• Allows manual telescope movement with optional shaft encoders
• Southern and Northern Hemisphere operation
• Retains position information after power off (for permanent observatory use)
• EPROM upgradeable software

How accurate is Gemini? 

While some manufacturers claim incredible accuracies with their GoTo systems, few will actually state actual results as shown above.

While single star alignment assumes that your Losmandy mount is accurately polar aligned, the Gemini system only requires rough polar alignment to deliver excellent pointing accuracy across the entire sky using multi-star alignment models.

The above CCD image mosaic demonstrates the early pointing accuracy of the Gemin/G-11 system, using a three star alignment model, the telescope was slewed from (in rows, left to right)  Antares, M16, M17, Bug Nebula, M57, M8, M22, M27, Optus 1b geosyncronous satellite (small streak lower frame). At the completion of each slew, no fine adjustment was performed, and a single 20 second CCD exposure was taken.

As can be clearly seen, the tracking accuracy the Losmandy Gemini system is excellent, even without PEC, which was not used in the above exposures, stars are perfectly round. The PEC menu allows for permanent error corrections to be stored in the non-volatile memory of the Gemini system.

Gemini +
The Ultimate Hand Controller

Pictured is a palm PC being used with The Sky pocket PC software to control a Losmandy/Gemini mount. What makes the system unique is Gemini's ability to align on a PC object.

Just tap on an object on the Palm PC display and slew to it. Any residual position errors can quickly be modeled by Gemini's additional align to PC object function.

Up to 256 stars on each side of the meridian can be used to create a pointing model. You do not have to know the name of the alignment star.... just tap on it!

Only Losmandy Gemini gives you T-Point like accuracy in the field with no other software or accessories!

Gemini's non-volatile memory and Real Time Clock data also allows the system to be powered off, and restarted at a later time with no loss of modeling data or positional information. The re-start position accuracy is only limited by the accuracy of the internal clock, which can be updated to within a fraction of a second via a PC.  These features make the Gemini system ideal for Astrometric and Photometric surveys (e.g. Comet and Asteroid hunting, Supernova patrols, Variable star studies) and are well suited to permanent telescope installations.

You can find out much more about the Gemini System on Losmandy's own pages on the Gemini System

Click here for: 
Instruction Manual - Level 4 (pdf)
Gemini Quick Start
Gemini Software page
Gemini Servo Motor Installation Instructions