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RENE GOERLICH'S GEMINI ASTRONOMICAL TELESCOPE POSTIONING SYSTEM
Control system as offered for our Losmandy German Equatorial Mounts

Gemini System Ovserview

Gemini Instruction Manual

Gemini Quick Start

Gemini Software and Update page

Gemini Servo Motor Installation Instructions

An Explanation of the Gemini System ROM Levels

The Gemini System provided with our Losmandy Mounts includes an evolution of the mount operating functions described on the main Gemini system description page. The mount operating instruction set (or "operating ROM") is a socketed computer chip, housed in the Gemini Console illustrated at right.

Losmandy "Gemini" control system Console. This houses the control circuitry of the Gemini system, and the interface to external components, power supply, and motors.

The basic functions provided with the mount are referred to as "Level 1 ROM". These have evolved as bugs were worked out of the Gemini, and these changes are referred to as "Version" changes. So a chip that is "Level 1, Version 1" is not as desirable as "Level 1, Version 1.1". By the year 2002, Rene Goerlich had developed the Gemini to provide three levels of functions (1, 2, 3) each with increased functions and capabilities. To change from one Level to another, or to upgrade from one Version to a more refined Version simply requires one to acquire that chip, then install it into the Gemini Console.

An upgrade chip to Level 3 (sometime written "Level III") and Level 4 are available for a relatively modest fee. While it is possible to buy the chip and upgrade at some later time, Company Seven suggests that for most people is worth while to order this upgrade factory installed with a new Mount since it will become confusing to learn a new menu all over again if one transitions from Level 1 or 2, to Level 3 of 4 as an aftermarket upgrade at a later time.


The official Gemini developer's site gives Gemini users additional information to make best use of their telescope control system. Please contact the mount manufacturers or one of their dealers if you want to order the Gemini hardware for your mount. Check this site or contact Rene Goerlich if you already have the Gemini and want to upgrade the software to a higher level, if you want to propose new features to be added, or if you experience problems.

The Gemini System comes with the German Equatorial Mounts GM-8, G11, Titan and HGM-200 produced by Scott Losmandy and with the MI-250 by Mountain Instruments. It can also be used to control other mounts, f.i. the Celestron CI mount.

The Gemini is a sophisticated computer controlled servo system with lots of valuable features.
Based on 3 microprocessors (one per axis and a main CPU), it is self-contained and fully functional without the need for PC control in the field.


Software Versions

To allow for an ongoing development, Gemini software is build and supplied in several levels of functionality. The Gemini system is currently sold (with a mount or as a retrofit) with Level 3 software. Within each level, the software is maintained and changes are indicated by a version number. Levels 1 and 2 are no longer supported, an upgrade to Level 4 is recommended.

Changelog of the software released so far:

Initial Level 1

Level and Version Release Date Changes
Level 1, V1.0 November 2000
  • Original release
Level 1, V1.1 December 2000
  • Correct rounding for southern hemisphere SAO stars declination seconds.
Level 1, V1.2 January 2001
  • TVC speed reduced to 16x sidereal.
  • Change in reply to :MS# command in case the Gemini rejects a slew because the target object is below the horizon.
  • Menu point Setup->Set Timer renamed to Setup->Set Date/UTC.
Level 1, V2.1 July 2001
  • Extended Serial Command Set (see link below).
  • New Synchronize command under the Alignment menu point allows for adjusting the coordinates to an object without affecting the modelling parameters.
  • Quick Menu selection: Pressing the Menu button for more than a second scrolls a choice of Centering Speeds and Visual/Photo Mode through the display. Releasing the button selects what is just displayed.
  • A slew operation from the PC can be started into an ongoing slew.
  • More ruggedized Startup Mode selection procedure.
  • Automated restart by a watchdog timer in case of software failures without loosing alignment and modelling data, giving debug information.
  • Setup->Reset Defaults allows for selection between Losmandy or Mountain Instruments default values.
Level 1, V2.20November 2001
  • Ruggedized autoguider readout.
  • Gemini starts up in the serial command precision mode that was active at shutdown.

Remote Control Level 2

Level and Version Release Date Changes
Level 2, V1.1 September 2001
  • All Level 1, Version 2.1 features.
  • Additional Native Serial Command Set to allow extended Remote Control and access to the internal parameters (setup values, telescope modelling, ...).
  • More internal databases.
  • Downloadable 4000+ object User Catalog.
  • All significant actions are logged into an Observing Log that can be uploaded to a PC.
  • MS Windows® Gemini Control Program for Remote Control, including setup of the Gemini, choosing startup mode, manual control, scripted GoTo operations, down- and uploading modelling parameters,... available for free download, but out-dated
Level 2, V1.2 November 2001
  • Ruggedized autoguider readout.
  • Gemini starts up in the serial command precision mode that was active at shutdown.


Professional Level 3

Level and Version Release Date Changes
Level 3, V1.00 September 2002
  • All Level 2, Version 1.2 features.
  • Many new features, described here
Level 3, V1.01 October 2002
  • Sync'ing and "Image Link" using TheSky now possible without a prior slew.
  • UTC Date/Time, Mount Type, Longitude, Latitude can be set directly at Cold Start.
  • Actual UTC Date/Time, Mount Type, Longitude, Latitude values are displayed after startup.
Level 3, V1.02 &
Level 3, V1.03
September 2003
  • Bugfix for Titan autoguiding.
  December 2003
  • MS Windows® Gemini Control Center, now fully supporting Level 1, 2 and 3 features, and providing additional computer-controlled functionality.
Level 3, V1.04 March 2004
  • Beta version for Titan mounts with 50:1 spur gears (Titan50).
Level 3, V1.05 March 2004
  • Bugfix for wrong direction correction by PAC (Polar Axis Correction) at the southern hemisphere.
Level 3, V1.10 June 2004
  • Support for Titan50.
  • PAC corrected for the Southern Hemisphere.
  • GPS receivers probed at 4800 and 9600 bit/s.
  • Mount type defaults to Titan.
  • Slewing speeds default to 800x.
Level 3, V1.11 June 2004
  • Bugfix for Titan50 PEC.
Level 3, V1.12 September 2004
  • Bugfix for SRAM parameter initialization after a CMOS Reset (f.i. after a battery swap).
Level 3, V1.13 October 2004
  • Outside the Safety Limits autoguider corrections are ignored, tracking is not restarted.

Universal Level 4 software

Level and Version Release Date Changes
Level 4, V1.00 April 8, 2006
  • Completely redesigned software, supporting custom mounts and remote hand controller emulation.
  • Many new features, described here
Level 4, V1.01 April 10, 2006
  • Too slow guiding speed in DEC after changing the guiding rate using command >150 corrected.
Level 4, V1.02 May 1, 2006
  • Movements at Guiding Speed are also supported in Terrestrial Mode.


Upgrade Gemini to the latest software

Owners of a Losmandy Gemini System are entitled to upgrade to the current software. This can be done by replacing Gemini's socketed eprom chip. The new software is available for free download.

You need an 512kx8 EPROM in the DIP32 package, up to 120ns access time, 150ns usually works, too. Examples are STS M27C4001, National NM27C040 or Fairchild FM27C040. Please use the eraseable kind with the little window allowing for erasing the content with special UV light, not the OTP (one time programmable).

The software is available as an image in Intel HEX record format or in binary form. Please be sure to select the the correct format programming device.

Often computer and electronics shops offer to burn images into EPROMs. Don't forget to cover the UV window after erasing and before burning the new image into the EPROM.


Instead of programming a chip yourself those who bought their systems from Company Seven can buy ready to use Gemini Eproms through us.

Level 3 Version 1.13 software is still available as

Please inquire.

Company Seven makes the current Level 4 Version 1.02 available on line:

You may want to use the "Save Link Target As" feature of your browser.

Here's an article "Replacing the GEMINI System EPROM Chip" explaining how to locate and replace the EPROM .


Manual and serial command set descriptions

Gemini offers many features to the beginner as well as to the expert. To make best use of it I highly recommend to read the very comprehensive manual written by Dave Sandage, Michael Rudolph and me. The manual is available for download in Portable Data Format (.pdf):

Software developers wanting their programs to communicate with the Gemini: Here are the Serial Line Command Interface Descriptions (these links will open new browser windows) :

Gemini Accessories

If you want to connect a cute little GPS receiver to set your mount's date, time and location automatically a startup, check for the GPS-6010 or GPS-6010-LX receivers (the link opens a new browser window)!

A star chart with Gemini's bright and alignment stars can be found at duchekconsult.com.

With Level 4 software, the hand controller functionality can be emulated over the serial line. This allows to use the DB-15 HC socket to be used as a second serial port.
Thunderbird Electronics Inc. provides a serial RS232 adapter for the HC port:

2nd Serial Port adapter


Gemini Control Center GCC for MS Windows®

You don't like to work through the menus of the Gemini? You'd like to save the settings into a file and download them if necessary? Save the well tested modelling parameters for your permanently mounted telescope? Or script control your telescope?
Level 3 and 4 software together with the Gemini Control Center contributed by the developer's son Daniel puts you in full control at the keyboard of your PC.

Gemini Control Center

Visit Dr. Görlich's web site to read a detailed overview of the capabilities of the Gemini Control Center while working with the Level 3 software. For download and installation, please follow the instructions on this page !

Mike Rudolph and Daniel Görlich have written a comprehensive manual for the GCC (1 MByte .pdf file).

Gemini Control Center GCC for PDA

Gemini hand controller emulation takes over:

PDA hand controller


Analyze and reduce Periodic Error with PEMPro

PEMPro by CCDware PEMPro now fully supports Gemini Level 4 Firmware. This allows for dramatic correction and refinement of PE for all Gemini equipped mounts: PEMPro provides direct upload and download of PEC curves to Gemini firmware and beta testers have reported an average of 80% reduction in Periodic Error using the new L4 firmware and PEMPro 1.6.

For technical information regarding specific Gemini L4 support please contact siriusimaging.com PEMPro technical support.
For more information about purchasing or upgrading to PEMPro Version 1.6, please visit: www.ccdware.com.


Databases

Level 3 and 4 software contain:
... and 4000+ User Catalogues objects down- and uploadable via the serial interface.

You can prepare your observations by building user catalogues using your computer and and downloading them into the Gemini using the Gemini Control Center. Well prepared observing, together with the automatic logging of your actions, can be much more effective.

It is not possible to upload Gemini's databases to your PC. If you want to compile your specific observing lists for the night using the objects from the Gemini's databases, here they are in the Gemini User Catalogue (.guc) file format. You can download them, copy and paste your targets using your favorite editor, building up your specific programs for the night.


Additional Information

If you want to share experiences with other Gemini users, there are two Yahoo groups online:

DATABASES:

Level 1 software contains

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!

Level 2 and 3 software additionally contains

You can prepare your observations by building user catalogues using your computer and and downloading them into the Gemini using the Gemini Control program. Well prepared observing, together with the automatic logging of your actions, can be much more effective.

It is not possible to upload Gemini's databases to your PC. If you want to compile your specific observing lists for the night using the objects from the Gemini's databases, they are available in the Gemini User Catalogue (.guc) file format. You can download them, copy and paste your targets using your favorite editor, building up your specific programs for the night.

In Addition to Database Differences, Features in Level 3 Include: