Campanola CAN18 Instruction Manual page 45

Local sidereal time
Hour angle
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This is the angle (vernal equinoctial point hour angle) measured while
turning to the west, from the starting point of the meridian of the
observation point to the vernal equinoctial point. Instead of degrees,
minutes and seconds, it is converted into hours, minutes and seconds
(0h - 23h 59m 59.9...s) with 15° = 1 hour. You can get the local sidereal
time by finding the one corresponding to the current day from the date
markers for the local sidereal time (based on the noon of the universal
time in the average year) on the rim of the 24-hour dial and reading
the 24-hour marker on the dial ring pointed by the date marker of the
current day.
With the meridian as the starting point, this is the angle measured
while turning to the west as far as the target celestial object (or point).
Usually, the hour angle is also expressed in hours, minutes and seconds
instead of degrees, minutes and seconds, converted with 15° = 1 hour.
Also, celestial objects on the east side may be measured by turning east
from the meridian and expressed with a negative value (−).