[tz] What's "right"?

[Paul Eggert]

On 11/13/20 6:29 PM, Steve Allen wrote:
> On Fri 2020-11-13T15:51:49-0800 Paul Eggert hath writ:
>> It may well make
>> sense, though, for some astronomical applications to do the conversion
>> "correctly", when interpreting historical astronomical data.
> 
> For the past 25 years the range residuals to Mars fall inside an
> envelope 2 meters big.  Similarly tight ranges apply for every other
> planet that has had an orbiter or lander.  Trying to construct an
> epemeris by adding in older observations does not improve the result,
> it only adds noise.

All true. I was thinking of more of historical astronomy, something like "How 
accurately were astronomers taking measurements in the 1970s?".

PS. To be honest I was also thinking of less-navelgazing questions, such as "Has 
the gravitational constant changed in the last century or two, and can we tell 
this by looking at old records?" but now that I've looked into that particular 
question I was blowing smoke. Recent research on possible variations in the 
gravitational constant have been more along the lines of constraints from Big 
Bang nucleosynthesis or from asteroseismic measurements, and circa-1970 
astronomical records are useless for that.