NavList:

Peter Blaskett, you wrote:
"Further to the discussion about the refraction, when using the old DOS software ICE, instead of newer implementations of the navigation data, I get this result.
The calculated refraction here seems to be correct."

Ahh, thank you! I have been meaning to do just that, but I couldn't get DOSBox running in a readable display output on my current high-resolution laptop*. And yes, I agree that my "USNO clone" output should match the (very) old ICE software (Interactive Computer Ephemeris, copy attached below) since that's almost exactly what was behind the USNO AA web app. Right now, it doesn't match --and in just the way that Antoine described-- so I'll see if I can adjust it without wasting too much time.

Frank Reed

*I was able to get it working shortly after I saw your message. If anyone else is interested in setting this up in DOSBox on a Windows machine with a high-resolution display, try these settings:

fullscreen=false
fulldouble=false
fullresolution=original
windowresolution=2048x1536
output=ddraw

Note that windowresolution can be any other 4x3 pair, and 1024x768 will work better on non-4k devices.