Aero-Terms are designed to be a daily reminder of the terms,
names, acronyms and explanations of the unique language that
populates the aviation world. Aerospace, sport aviation, fixed
wing, helo, you name it... it's all fair game.
Aero-Terms should serve as a quick but intriguing reminder of
the terms you may use every day, or an introduction to an aspects
of the Aero-World you may not yet be familiar with. ANN also
encourages readers to go beyond the FMI link, and further research
any intriguing terms.
The angle between an observer's meridian and the hour circle on
which some celestial body lies. This angle is conventionally
expressed in units of time (hours, minutes, and seconds), which
gives the time elapsed since the celestial body's last transit at
the observer's meridian (for a positive hour angle), or the time
unit the next transit (for a negative hour angle).