The Tactical Screen

The Tactical Display is typically used to give an overview of the player ship's immediate position. Similar in appearance to the Helm and Weapons consoles, it covers approximately four times the maximum range of those consoles. Allied and Enemy ships can be seen on this screen if they are within sensor range, as well as various space terrain features such as Asteroids, Minefields, Nebulae, and Black Holes. These objects can be seen at a greater distance than they can be seen from the visual Mainscreen display, or on the Helm or Weapons consoles.

As with Long Range Sensors, what can be seen on the Tactical screen may depend on the "Sensors" setting on the server setup screen. At the minimum levels, 16k, 11k, and 8k, enemy ships will not appear until they are within the "compass ring" in the center of the display. In fact, the compass ring itself appears to define the 16k range. Objects will not be visible on the Mainscreen until they are within 7.5k, which is well inside the compass ring. Enemy ships can also remain unidentified on this display, unless they are scanned by Science or get within 7.5k. (The grey ship marked "G22" in the image is an example of this)

Also as with Long Range Sensors, power put into the Sensors system effects the Tactical screen. Less than 100% power will cause the Tactical screen to flicker, and the lower the power level, the worse the flickering. Damage to the tactical system will also cause flickering, or even complete lack of Tactical screen if the system is completely damaged. 

Enemy ships that enter nebulas will not appear on the Tactical Display. This includes ships that are close enough to be in visual range. Some elite enemy ships may have the power to appear invisible to this screen even outside nebulas. (And Long Range Sensors as well) Ships that are invisible to this screen but in visual range can usually be seen by switching the Main Screen to an external view. The Science console can see these ships as well. (Some elite ships may also be using a Cloak, which is invisible to all screens, but only temporarily)

When targets are selected by Weapons, Science or the Captain's Map, the targets chosen are also displayed on Tactical, if they are in range to be seen on this display. This feature can be used by the Captain or Science as a "pointer" to indicate a given target while discussing it with other crew members. Helm and Weapons will also see the selection on their consoles, if in range.