Re: Moon Venus Lunar - Interpretation of results
From: Jim Rives
Date: 2020 Jan 31, 17:46 -0800
In your reply you said:
"But when you are doing lunars, what you are concerned about is the speed of the Moon against the background of the fixed stars. The Moon is moving at about 12 degrees per day across the sky, so you would expect any lunar distance to a star (near the ecliptic), or Venus in this case, to change by about 12 degrees per day. That is about 30 minutes of arc per hour.
So, if have an error of 16' in your lunar distance, that actually amounts to about 32 minutes error in time."
I knew that I was determining the error of the LD, but couldn't relate that error to the sun's movements (or longitude). Using the lunar rate and the error in the observed angle give you time. And time is a solar concept (probably getting in over my head here). But knowing time and the sun's rate, you can translate that to both time/ and longitude.
I just had absolutely no idea how the Error in Lunar and the Approximate Error in Longitude were related. The next few lunars I'll be sure to manually recalculate Frank's Lunar calculator output to let it sink in. Thank you for the help.