NavList:

There's a sometime-synonym for getting "longitude by lunars"... in many sources, especially in recent decades but also historically, it's called longitude by "lunar distances". The catch with that expression is that a "lunar distance" for most people, including navigators, sounds like the distance to the Moon. But it's intended to signify the angle across the sky from the Moon to some other celestial body. "Lunars" as a name for the method works better on that score. Ironically the greatest correction to a "lunar observation" --an angular lunar distance-- is the Moon's parallax which is a measure (inverse) of the linear, physical "lunar distance". That is, the "lunar distance" as a physical distance in miles (or km) has a significant impact on the "lunar distance" as an angle in degrees.

Speaking of lunar distance, we are now, as I write this, about fifteen minutes away from a new "lunar distance" record (physical distance in miles) for astronauts. The astronauts of the Artemis II mission will then be farther away than any humans have travelled from Earth ...ever. That's an achievement worth noting.

Frank Reed