CCDASTRO Temma Mount Driver

An ASCOM telescope driver for Takahashi Temma and Temma 2 equatorial mounts. The driver is a C# local COM server that retains the native Temma serial protocol while replacing the original VB6/ActiveX implementation.

Current version: 1.0.20

What it supports

• Connect and initialize supported Temma mounts
• GOTO slews and slew-abort handling
• Coordinate synchronization
• Sidereal tracking on/off through Temma standby control
• Manual axis motion and pulse guiding
• Configurable mount model and speed selection
• OTA East, OTA West, Counterweight Down, and Counterweight West startup references
• Driver-side ASCOM park and unpark state
• Multi-client ASCOM local-server operation and optional diagnostic logging

Supported mount selections include EM-11, EM-11 Temma 2M, EM-200, EM-200 Temma 2M, NJP, and EM-500.

Requirements

• Windows
• ASCOM Platform installed
• .NET Framework 4.7.2 developer/runtime support for building from source
• A Takahashi Temma-compatible mount and serial connection

The Visual Studio project targets x86 because it is an ASCOM local COM server. It can serve both 32-bit and 64-bit ASCOM client applications through COM.

Serial connection

The Temma serial connection is configured as:

Setting	Value
Baud rate	19200
Data bits	8
Parity	Even
Stop bits	1
Line ending	CRLF
DTR	Enabled

Select the COM port and mount configuration in the driver's ASCOM Setup dialog before connecting.

Startup reference

Temma controllers need a known physical reference after startup. Select the actual mount position in Setup before connecting:

• OTA East or OTA West establishes the corresponding Temma pier reference.
• Counterweight Down uses the physical celestial-pole reference: true north / site latitude in the northern hemisphere, or the corresponding south-pole reference in the southern hemisphere.
• Counterweight West follows the legacy Temma reference geometry from the original driver.

The driver sends the required Temma T, I, Z, and D initialization commands and validates the R0 sync acknowledgement.

Tracking and standby

Temma uses inverted standby terminology:

Command	Temma state	ASCOM meaning
STN-OFF	Standby off; RA motor enabled	Tracking on
STN-ON	Standby on; RA motor stopped	Tracking off
STN-COD	Query standby state	Query tracking state

The driver presents normal ASCOM Tracking semantics to client applications.

Park and unpark

Temma has no dedicated protocol-level park command. Park and unpark are maintained by the driver:

• A configured park position is stored as physical Alt/Az plus pier-side information.
• Parking stops motion and turns tracking off.
• While parked, the driver reports the stored park position rather than a potentially stale raw mount coordinate.
• Unpark restores the Temma sky-coordinate reference from the saved physical park position and restores tracking when appropriate.

For a meaningful park azimuth, avoid an altitude of exactly 90 degrees: azimuth is undefined at the zenith. Use a value such as 85 to 89 degrees instead.

Building and registering from source

1. Open ASCOM.CCDASTRO.Temma.sln in Visual Studio.

2. Build the Release | Any CPU configuration. The project itself targets x86.

3. From an elevated Command Prompt, register the generated local-server executable:

   ASCOM.CCDASTROTemma.exe /regserver
   

4. Open an ASCOM client such as N.I.N.A., choose CCDASTRO Temma Mount Driver, and configure it through Setup.

To unregister the local server:

ASCOM.CCDASTROTemma.exe /unregserver

Do not use RegAsm for this local-server executable.

Diagnostic logging

Enable tracing in the driver Setup dialog when diagnosing a connection or protocol issue. ASCOM logs capture serial transmit/receive traffic, initialization, sync, slew verification, park, and unpark activity.

Useful files are normally named similarly to:

ASCOM.Temma.Driver.*.txt
ASCOM.CCDASTROTemma.LocalServer.*.txt

Protocol behavior

The driver follows the Temma command/reply model:

• E reads coordinates.
• P starts a GOTO and expects R0 through R5 status responses.
• D synchronizes coordinates and expects R0.
• PS aborts a slew and is sent without waiting for a reply.

Slew completion is determined from observed settled mount motion rather than requiring an unrealistically exact target-coordinate match. This matches the proven behavior of the original VB6 driver and accommodates normal encoder resolution and pointing error.

Validation status

Version 1.0.20 has been exercised with a real Temma mount for connection, OTA-East initialization, sync, repeated GOTO slews, slew completion, and abort behavior. Counterweight-reference and park/unpark/reconnect behavior have also been verified with the companion Temma simulator.

Author

Chuck Faranda
CCD Astro Observatory Automation
https://ccdastro.net