Temperature Coefficients

The temperature compensation coefficient is a calculated number that the TCF uses to determine how much to adjust the focus as the temperature of the scope body changes. This coefficient is unique to every telescope setup and thus must be "learned" to the device by the user.

Viewing the Current Temperature Coefficients

You can easily view the temperature compensation coefficients that are saved via the Setup Dialog. From the top menu bar select Setup/Device Settings. The coefficients are labeled Mode 'A' Coefficient and Mode 'B' Coefficients. If you have previously determined the temperature coefficient for your setup you can manually adjust the property on the form. The driver must be "Connected" to the device in order to obtain and change the temperature coefficients because these values are stored in the devices internal memory.

Calculating the Temperature Coefficient

The best way to determine the temperature coefficient for your setup is to utilize a client application such as FocusMax that uses image processing feedback to obtain a nearly perfect focus. If you have an auto-focusing application available to you see the help page Temperature Coefficient Wizard which is a tool that is included with the driver install that can help with calculating temperature coefficients.

The following process can be used to set the temperature coefficient without the use of auto-focusing software.

Make sure that you TCF-S driver is loaded properly and that you can connect to the Focuser.
Open up the drivers Setup Dialog by selecting it in the 'Chooser' and clicking the Properties button.
Connect to the focuser and move the focus in or out until the best focus is achieved at the current temperature.
Once the telescope is in focus click Setup/Temperature Coefficients/Set Start Point as shown below. Use the form to capture a start point for the coefficient calculation.

After you have captured a start point for the coefficient calculation wait for the temperature to drop a minimum of 5�C. The larger the temperature drop you allow, the more accurate your coefficient will be. Once a temperature drop has taken place move the focuser in or out using the In and Out buttons until the telescope is in focus again at the new temperature. When the best focus has been achieved click Start/Temperature Coefficients/Set End Point.
The Set End Point Form will guide you through the process of capturing the end point data, calculating the temperature coefficient, selecting a mode (A or B) to associate the new coefficient with and finally storing the coefficient to the device memory.

Manually Entering a Temperature Coefficient

If for any reason you want to manually enter a temperature compensation coefficient you can do so easily via the setup dialog. On the top menu bar select Setup/Device Settings, if the device is connected you can enter in any temperature coefficient in the acceptable range (-998 to +999).