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Finding the maximum height of a star

In astronomy, height refers to the angular distance between a celestial object and the horizon. The maximum height that any object will attain on a given day is when it is directly south on the meridian (i.e. the vertical line running through the center of the astrolabe). Thus asking what the maximum height of a star is equivalent to asking how high it will be when it is on the meridian. The height of a star can be read by estimating where it is with respect to nearby almucantars. The height of each almucantar is indicated on the meridian.

Example: What is the maximum height that Rigel will attain on any given night? To answer this question, rotate the rete until Rigel is on the meridian (see below). Rigel is a little more than halfway between the 30 and 40 degree almucantars (the scale is written on the meridian.) A good estimate might be 37 degrees above the horizon. Thus Rigel will never be more than 37 degrees above the horizon in Stevens Point, Wisconsin.