RedShift provides several ways to control which part of the sky you are looking at (the direction of view):
  • Centering on a space object
  • Double clicking anywhere in the sky window
  • Centering on specified co-ordinates

    23.1 Centering on a space object

    If you know the name of the object you want to observe (such as a planet, a star or a comet) use the Select target object pop-up menu in the Aim panel. Click the name of an object in the sub-menus to center your view on it. To find an object in the RedShift catalogues choose Find object to open the Find object dialog.

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    You can also click any object in the Sky window. The selected object is highlighted. Click the name of the object to open the Object Info window for the selected object. Click Center in the Object Info window to center your view on the selected object.
    The name of the currently centered object is displayed in the Target object box.
    23.2 Locking your view on an object
    Use the lock button in the top right of the Aim panel to lock your view on the currently selected object. The Target object box displays a locked symbol when the direction of view is locked on an object. You can also lock your view on an object by clicking Lock in the Object Info window. The lock button only works if you have already centered on an object.
    Locking your direction of view is useful if you want to track the motion of an object such as a planet or moon. If you center on a planet or moon and then run time tracking without locking your view on the object, the object may move from the center of the sky window.
    Note that you cannot change the direction of view while your view is locked on an object. Unlock your direction of view by clicking the Lock button (in the Aim panel) off.

    You can also lock and unlock the direction of view using the Select aim menu in the Track aim panel.
    23.3 Entering new viewing direction co-ordinates
    The simplest way to center on any point in the sky window is to double click on it. You can also center your view on any point in the sky by entering its co-ordinates.
    Click the re-size button in the top right of the Aim panel to display/hide the co-ordinates settings boxes.
    The co-ordinates of the center of the screen are generally expressed relative to the celestial equator (the Right Ascension/ Declination system). If you are using Observe from surface mode, you can also display the co-ordinates of the center of the screen relative to the horizon (the Azimuth/ Altitude system).
    For an explanation of the Right Ascension/Declination and Azimuth/Altitude co-ordinates systems, please see the relevant entries in the online version of the Penguin Dictionary of Astronomy.
    Right Ascension/Declination (or Azimuth/Altitude) are set using three fields: direction (+/-), degrees or hours and minutes.
    You can enter new viewing direction co-ordinates by editing the values in the Right Ascension/Declination (or Azimuth/Altitude) fields. Click a value to select it then type new values. Use the tab key to step through each of the fields. Press Return/Enter to apply the new direction of view.
    Alternatively, you can select a preset value from the co-ordinates settings pop-up menu.
    23.4 Changing viewing direction using the Control panel
    You can move your viewing direction through a sequence of positions using the Control panel (Direction mode). This is the equivalent of slewing the direction of a telescope across the sky.
    Choose Direction mode from the pop-up menu in the Control panel, (or press F7 on the keyboard). Use the horizontal and vertical controllers to move your viewing direction east or west and north or south. Click the play arrows (, , , ) to move continuously through either axis using the currently defined step size (expressed as degrees and minutes). Click the stop button to stop continuous movement. Click the buttons immediately to the right and left (and above/below) the stop button (, , , ) to move one step at a time, or use the corresponding arrow keys on the keyboard.

    You can also choose to change direction with respect to RA/Dec, Alt/Azm or the computer screen.

    Edit the value in the step field to change the current step size, or use the pop-up menu to select one of the pre-set values.
    23.5 Setting the base plane
    The Sky window view in RedShift is always oriented (its tilt is controlled) relative to a particular base plane. By default, the appropriate base plane is chosen for the present Location mode. You may wish, however, to vary the slope of the display. The base plane controls allow you to do this in a variety of ways. A new feature of RedShift 3 is the ability to control the roll angle relative to the selected base plane.
    Click the re-size button in the top right of the Aim panel to display the Select base plane pop-up menu and the Roll angle box.

    Use the Select base plane pop-up menu to choose one of six different base plane settings:
  • Horizon plane - the local horizon when in Observe from surface mode
  • Celestial equator
  • Eq. Object - the equator of the object which the current location relates to (i.e. the
  • Earth's equator if location is currently set to the Earth's surface or tracking Earth)
  • Ecliptic plane
  • Galactic plane

    Note that the available base plane settings vary depending on the location mode currently selected.

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    Use the Roll angle field to enter the value of the roll angle relative to the currently selected base plane. Click the field in the roll angle box to select it. Enter a new value. Press return/enter to apply the new value.
    The Roll angle is counted from the base plane clockwise (+) or counter-clockwise (-).
    By default, the base plane is locked; this means that as the view changes, the roll angle relative the base plane is fixed. In some cases you may wish to unlock the roll angle. See Track aim panel for more information.
    23.6 Changing roll angle using the Control panel
    You can move your roll angle through a sequence of positions using the Control panel (Roll angle mode).

    Choose Roll angle mode from the pop-up menu in the Control panel (or press F8 on the keyboard). Use the controller to move the roll angle (CW means clockwise, CCW means counter-clockwise). Click the play arrows (, ) to move the roll angle continuously using the currently defined step size (expressed as degrees and minutes). Click the stop button to stop continuous movement. Click the buttons immediately to the right and left of the stop button to move one step at a time, or use the corresponding arrow keys on the keyboard.

    Edit the value in the step field to change the current step size, or use the pop-up menu to select one of the pre-set values.
    23.7 Setting the zoom factor
    Zoom controls the angle of view that is displayed. Increasing the zoom factor decreases the area of sky that is displayed.

    RedShift 3 lets you enter a zoom factor anywhere between 0.2 and 9999. Zoom factor 1 shows roughly the amount of sky that your eye takes in. This is quite a wide angle view for the computer screen, so objects seem smaller than normal. Choose a zoom factor of 3.5 to make objects seem roughly normal size. Bear in mind that setting a very large zoom factor may result in nearby planets and moons obscuring your view.
    Edit the value in the Zoom field to increase or decrease the Zoom factor. Click the value in the zoom field to select it. Enter the new value. Press return/enter to apply the new value. Or select one of the pre-set values from the zoom factor pop-up menu.
    The Zoom factor can also be changed using the + and - keys on the keyboard or by using Zoom mode in the Control panel.
    Note that resizing the Sky window (main RedShift window) changes the angle of view, but does not change the zoom factor (i.e. it does not change the angular separation between objects in the Sky).
    23.8 Changing zoom using the Control panel
    You can increase or decrease the zoom factor through a series of values using the Control panel (Zoom mode).

    Choose Zoom mode from the pop-up menu in the Control panel (or press F9 on the keyboard). Use the controller to increase or decrease the zoom factor. Click the play arrows ( , ) to increase/decrease the zoom factor continuously using the currently defined step size. Click the stop button to stop continuous change. Click the buttons immediately above and below the stop button to change the zoom factor one step at a time, or use the corresponding arrow keys on the keyboard.

    Edit the value in the step field to change the current step size, or use the pop-up menu to select one of the pre-set values.