Main Screen

The PHD2 main window is designed for ease of use and clarity.  Its intent is to support a quick and natural sequence of interactions to start and control guiding.  The basic steps for doing this are as follows:
  1. Connect to your guide camera and mount
  2. Start a sequence of guide exposures to see what stars are available in the field of view
  3. Choose a guide star and calibrate the guider
  4. Continue guiding on the target star while using various display tools to see how things are going
  5. Stop and resume guiding as necessary

The majority of the screen is taken up by the display of the star field from your guide camera.  The display is automatically adjusted for size, brightness, and contrast so you can have a clear view of available stars.  However, these adjustments are done only for display purposes.  Internally, PHD2 operates on the raw, un-adjusted data in order to maximize guiding accuracy.  This display is also used to select a guide star by simply clicking on it.

Basic control

Near the bottom of the screen are the main controls.  PHD2 is largely controlled by these buttons and sliders, with additional pull-down menus at the top of the window for more detailed functions.  Moving from left to right in the window, the primary buttons are as follows:
  1. The camera icon - used to connect to your camera and mount devices
  2. The loop icon - used to start a sequence of repeated exposures with the guide camera ("looping"), with each resultant image (guide frame) being displayed in the main window.  If guiding is subsequently started, clicking on the 'loop' icon again will pause guiding while continuing to take guide exposures.
  3. The guide/target icon - used to start calibration, if needed, and then to start guiding on the selected star.  
  4. The stop icon - used to stop both guiding and looping
To the right of the stop icon is a pull-down list of exposure durations (0.01s - 15s).  You use this control to quickly set the guide camera's exposure duration.  If your camera does not support an exposure duration, PHD2 will do its best to emulate that duration.  For example, if you use a short-exposure webcam, your maximum true exposure duration might be only 1/30th of a second.  If you select one second as the desired exposure time, PHD2 will automatically acquire images for one second and stack them on the fly to create a composite image for guiding.

The next control to the right is a slider for adjusting screen stretch and contrast, essentially a "gamma" adjustment.  PHD2 automatically adjusts the display accounting for the darkest and brightest pixels in the image, and the slider is used to fine-tune the display to better see the stars in the field of view.  This may be useful, for example, if you are trying to focus the guide camera for the first time and need to see the large, out-of-focus star image. Moving the gamma slider only makes the display brighter or dimmer for your viewing. PHD2 always uses the raw pixels from the camera for guiding, and moving the gamma slider has no effect on guiding.  A display of "completely white" or "completely black" is usually an indication that no stars are available in the field of view.

Next to the gamma slider is the so-called "brain button."  This button brings up an Advanced Dialog for making detailed adjustments to PHD2's guiding operations.  A major design goal of the program is to minimize your need to change these parameters, but "the brain" is nothing to be feared - there are adjustments available here that can significantly improve your experience.  Over a period of time, you should take a look at this dialog and learn what it can do for you.

The rightmost control in this row is a "camera dialog" button.  This may be disabled ("grayed out") depending on the type of guide camera you have selected.  If it is enabled, you can click on it to set various parameters that are unique to that type of camera - binning and specialized gain settings are examples of such parameters, but there could be others depending on the camera.

Menus

The pull-down menus above the main guider display are used to access a variety of functions.  These are described in the Darks, Tools and Utilities, and Visualization sections of this help document.

Status Bar

The status bar at the bottom of the main window is used to display messages and status information that will help you keep track of guiding operations.  For example, the rightmost three panels on the status bar will show you whether the camera and mount are connected and whether the guider has been successfully calibrated.