About

Section 1.1 - About The Gemini

What Is Gemini?

The Gemini is a Focusing Rotator in a single compact package. The focuser has a full half inch (12.7 mm) of travel. The rotator has a full three hundred and sixty degrees of rotation. The whole package fits in a 2.75 inch (seventy mm) package when the focuser is fully extended. Both the Focuser and the Rotator are controlled from the same hub.

The Ever-Reliable Serial Port

Everyone knows that the serial port is almost extinct, right?   In truth, the serial port is still the most reliable standard communications protocol available and is used in several industries and applications, including observatory control. The RS-232 serial protocol is simple to implement, capable of communication over great distances and very reliable when used properly. To allow the hobbyist to easily write software for control of the focuser and for firmware upgrades, the Gemini system includes an RS-232 interface as standard.

Using Optec's Serial-USB communications cable, users can easily connect the Gemini controller to any modern PC even when no DB-9 serial port is available.  The Serial-USB cable includes an RJ-12 plug on the controller end and terminates in a USB converter on the PC end.  The original TCF-S focuser has enjoyed overwhelming success with these new communications cables.   Additionally, with the Serial-USB cable the 5 meter distance limitation of USB 2.0 is negated.  The Gemini controller includes a single 6-ft.long Serial-USB cable, but much longer cables, up to 50 meters in length, are available from Optec.

Wired Ethernet Connectivity

Gemini also supports Ethernet connections, allowing for large distances and easy remote control.  

Optional WiFi Connectivity

With the explosion of mobile devices capable of direct network communications, the Gemini system includes easy mobile access through iPhones, Android OS devices, and any other device with an Internet browser. With the purchase of the optional WiFi control board, connectivity to a Gemini is a snap.  Now observers, astrophotographers, and astronomy enthusiasts can completely eliminate the hassle of computer control cables by connecting to the Gemini over a wireless network.  Focusing can be accomplished without ever touching your telescope eliminating vibrations and thermal effects.

ASCOM Compatibility

The Gemini software package includes an ASCOM-compatible driver for both the Focuser and the Rotator. Therefore, the Gemini hub is usable with any ASCOM-compliant software.  Acting as an ASCOM Local Server, the Gemini requires ASCOM Platform 6.1 or higher for use.  

Please Note: This manual documents only the Gemini focuser hub and control software. Refer to the ASCOM Standards website (www.ascom-standards.org) for platform downloads and documentation.