Fast Continuous Telescope Focus Control
Developed in partnership with Innovations Foresight, Optec's new FocusLock software integrates patent pending SharpLock Technology to provide an easy-to-use focusing application that functions whenever guiding is active. When using the ONAG On-Axis Guider a cold-mirror passes infrared light to the guide camera while reflecting visible wavelengths on to the imaging camera. The cold-mirror introduces a slight astigmatism to the guide image allowing FocusLock to quickly determine on which side of focus the camera is currently positioned. Using the proprietary SharpLock technology, FocusLock can be used to quickly drive the focuser to the optimal focus position and maintain focus for weeks or months at a time.
FocusLock Focusing Software
Dr. Gaston Baudet of Innovations Foresight describes FocusLock Software in this YouTube video from The Astro Imaging Channel: https://youtu.be/Kt7sHp1ual4?t=806
What is FocusLock?
FocusLock is the first method of focus that uses real-time feedback continuously by sampling the optical quality of the guide image. Most methods of focus, including backlash compensation and temperature compensation, work by modeling the focus against a correlated physical parameter. These models can then be used to partially correct for changes in focus. However they cannot correct for any changes that fall outside their models.
FocusLock uses a different approach. By introducing a
slight astigmatism into the guide image, FocusLock is able to detect drifts in focus in real time and
continuously correct for them. This means that the system will correct for any source of poor focus, even if that source has not been modeled.
By coupling the focus to the guide star image, focus can be maintained
whenever the telescope is under auto-guider control.
Using FocusLock with the ONAG On-Axis Auto-Guider from Innovations Foresight both imaging and guiding cameras are par focal and use the same focuser. This means that any change in the focus at the guide camera will also change the focus of the main camera. When FocusLock detects a shift in focus it will correct the focus for both systems, keeping the main camera in perfect focus - all the time.
The ONAG uses a new, innovative and unique, patent pending technology from Innovations Foresight. Technical Innovations' ONAG has a special dichroic beam splitter (DBS) which is also known as “cold” mirror inside of it. This is basically an inferential filter.
The ONAG’s DBS reflects the visible light from the telescope to the imaging camera and passes the near infrared (NIR) light, which is usually useless for imaging purposes anyway, to the guiding camera for auto-guiding.
A full Test Report and description of the ONAG written by Dennis Di Cicco is available from Sky & Telescope magazine. (Link courtesy Sky Publishing Corp.)
How Does SharpLock Work?
Dr. Gaston Baudat of Innovations Foresight describes the ONAG and SharpLock in detail in this excellent Astronomy Technology Today article. Download for a full explanation and description of the technology that FocusLock is based upon. (PDF courtesy Dr. Gaston Baudat and Astronomy Technology Today.)
Why is FocusLock Better?
FocusLock represents a major upgrade to the original SharpLock software. SharpLock worked only with Maxim D/L and Astroart version 4. Optec software engineers have expanded the software to work with TheSky X, PhD2 Guide, and any ASCOM focusers, filter wheels, and ASCOM driven cameras. A much simplified interface features an easy to understand method for connecting devices.
At a glance, you'll be confident you're in focus as long as the Focus box displays Green. Yellow indicates that focus is within the classic definition of the Critical Focus Zone (CFZ) but not quite at the optimal focus, and Red means you're out of focus. Full scripting is available for automation and remote operations.
For those wanted to delve deeper into the focus operations, the original SharpLock Focus and Relative Roundness plots are still available. Simply click the View Plots option under the View menu.
Download FocusLock Today!
Visit our FocusLock Download page to download and try the latest version for 60-days, absolutely free. End your focusing worries and enjoy continuous, perfect focus for months at a time.
Full documentation and installation instructions are also available from the FocusLock Download page.