Using the altitude intercept method, if a star's altitude is calculated as 60° (Hc) but observed to be 61° (Ho), what is the implication?

In the context of celestial navigation using the altitude intercept method, the relation between the calculated altitude (Hc) and the observed altitude (Ho) provides information about the navigator's position relative to the geographical position (GP) of the celestial body, in this case, a star.

When the observed altitude (Ho) is higher than the calculated altitude (Hc), it indicates that the navigator is positioned closer to the star’s GP than expected. The difference between Ho and Hc is known as the intercept. In this scenario, the intercept is 1 degree (61° observed minus 60° calculated), which suggests that the navigator is closer to the star's GP by a certain nautical mile measure.

To convert angular difference into distance, navigators typically use the rule of thumb that 1 degree of intercept is roughly equivalent to 60 nautical miles. Therefore, with an intercept of 1 degree, this translates to being approximately 60 nautical miles away from the star's GP along the azimuth.

Thus, the implication of having a calculated altitude of 60° and an observed altitude of 61° indeed indicates that the navigator is 60 nautical miles from the star's GP along its azimuth, making this choice the correct one