Celestial Navigation with qtVlm: Circles of Equal Altitude

Following up on the video about plotting LOPs linked below, we show now how to find a fix with qtVlm by intersecting two circles of equal altitude. This is a fast accurate way to do sight reduction, taking into account the new option in qtVlm to use a circular earth radius for working cel nav problems. In the process we discuss the three possible solutions to a "Great circle distance" computation, being spherical earth needed for cel nav, approximate WGS84 using the average radius of the ellipsoid, and true ellipsoidal computations based on the ellipsoid of choice.

• Video on plotting LOPs is at    • Celestial Navigation with qtVlm: Plot...  
• Article on GC distances is at https://davidburchnavigation.blogspot...
• Our textbook on celestial navigation cited in the video is at https://www.starpath.com/catalog/book...
• Support and links for qtVlm is at https://www.starpath.com/qtVlm