Looking for the Wndsn store? This way, please.

398 pages, black & white. 129 graphics, 22 tables. Perfect bound. 8" x 5" (20.5 x 13.5 cm)

### Page 68

10 MIL = x100 = 5.729 0.5729°
100 MIL = x10 = 57.29 5.729°

### Page 270, Fig. 112

Figure 112 is supposed to represent Equation 19:

``````sin(ortive amplitude) = sin(declination) · sec(latitude)
``````

which can be calculated graphically as:

``````sin(ortive amplitude) = sin(declination) / sin(co-latitude)
``````

Figure 112 displays the calculation with a (correct) declination of -21.5° and a latitude of 52.5° instead of using the co-latitude of 90°-52.5° = 37.5°.

The correct graphical calculation looks like this: Calculating ortive amplitude with a Sine Quadrant using sin(declination) / sin(co-latitude).

With a result of 37° for the ortive amplitude.

In order to make the calculation more legible, we can transform the equation and do this:

``````sin(ortive amplitude) = sin(declination) / cos(latitude)
``````

which looks like this: Calculating ortive amplitude with a Sine Quadrant using sin(declination) / cos(latitude).

With a result of 90°-53° = 37° for the ortive amplitude.

Compare Tycho with a sunrise azimuth of 127° and thus an ortive amplitude of 127°-90° = 37°.

### Page 276, Eq. 25

The equation:

``````tan α_s = (sin τ / (sin φ · cos τ)) - cos φ · tan δ
``````

has to look like this:

``````tan α_s = sin τ / (sin φ · cos τ - cos φ · tan δ)
``````

Where an hour angle of 0° for noon yields an azimuth of 0°. For the azimuth from North, for a positive value of α_s subtract 180 - α_s and for a negative α_s add 180 + α_s.