DataScope

Since fluxgate compasses are magnetic compasses, they can only reference the earth's magnetic field. They can not reference the earth's inertia and therefore cannot be made to know True North.

If you wish to navigate in true heading, you have a couple of options. KVH's Azimuth 1000, Azimuth 314AC, GyroTrac, and Sailcomp 103AC allow you to enter an offset angle. This means that you can enter your local variation value (either positive or negative) and the compass display will show true rather than magnetic heading. When your variation changes because you have traveled a significant distance, however, that offset angle will not update automatically. You must update it manually.

The GyroTrac can also interface with a vessel's GPS, allowing the compass to learn the variation from the GPS. With this option, your GyroTrac will give true heading and will automatically update to the correct variation.

The DataScope housing does not include a threaded insert like those found on the base of cameras. As a result, there is no easy way to afix the DataScope to a camera tripod.

The Datascope has a backlit LCD display so you can read the units, time, etc., at night. This works great for viewing flashing markers and such. However, the Datascope is not manufactured with any sort of nightvision capabilities.

Yes, after you enter the local declination (variation).

Yes. The Datascope with show either a 12 hr or 24 hr clock.