TCF-Si Focuser
TCF-Si Focuser
TCF-Si Focuser


TCF-Si Focuser

Regular price
$ 725.00
Sale price
$ 725.00
Unit price

This item is out of stock but you can place an order now and we’ll ship when it becomes available.


Back in 1999 Optec's Gerald Persha designed and introduced the first all-digital motorized telescope focuser.  Featuring a closed-loop design with external hand control box and built-in temperature compensation, that very first TCF Temperature Compensating Focuser continues to operate every clear night at the Optec Observatory.  Utilizing a best-fit linear model to correct for temperature induced focal shifts, the TCF performs superbly without requiring a re-focus of the telescope for weeks at a time. 

As the first few focusers rolled out to customers, we quickly saw the need for PC computer control. By adding a serial UART chip and ASCII command set to the control circuit, the TCF-S was born.  Now focus control, along with serial "go-to" telescope mounts and imaging cameras could be controlled by a host of software packages.  

The remotely controlled observatory became a reality for many amateurs and small colleges using off-the-shelf products.  The revolutionary TCF-S was awarded a Sky & Telescope Hot Product award in 2000 for its contribution to this dramatic change in the way astronomy research and imaging was being accomplished. 

Since that time the TCF Focuser Series has grown to include larger focusers, focusers with integrated electronics, and new more durable controllers such as the FocusLynx which expands the serial protocols to include USB, Ethernet, and wireless WiFi capability.  Optec engineers continue the innovation with linear encoder versions for sub-micron positional accuracy.  Throughout all this growth, Optec has continually achieved the overarching goal of robust mechanical design with intelligent electronics for remote observatory operations.

#17668 TCF-Si focuser with Integrated controller

While the control box that comes standard with every TCF-S focuser is a useful compromise between remote computer control and telescope-side hand control, this system may not be for everyone.

Therefore, Optec has created integrated variants of our main line of focusers: the TCF-Si and TCF-S3i. Unlike their predecessors, these focusers feature an integrated control board that allows direct connection between computer and focuser, thus eliminating the necessity of the external TCF-S/S3 control box.

Transitioning to these integrated focusers from a TCF-S or TCF-S3 is incredibly easy. The focusing and temperature compensation controls are displayed within Optec's computer control software as a virtual control box, allowing any TCF-S/S3 owner familiar with the external control box to transition seamlessly to the computer-based integrated controls. Additionally, since the external control scheme of the TCF-S/S3 is replicated in the computer control software, new users of Optec focusers will have no more trouble learning to use the integrated focusers than their non-integrated counterparts.

For the TCF-S owner that favors the remote keypad over the control box, Optec has ensured that the TCF-Si/S3i are compatible with these controllers.

Finally, owners of non-integrated Optec focusers should know that the TCF-Si does not suffer any lack of functionality or precision due to the transition to an integrated control system. Similarly, the TCF-S3i retains the strength of the TCF-S3 while adding the integrated capabilities of the TCF-Si for a more streamlined focusing system.

    Personal Upgrade Path

    Buy risk-free: When it’s time to trade up you’ll get the most value for your used gear.