🚀 go-pugleaf

"Measuring" a *PEGGED* VELOCiTY c ought NOT be, too, messy.!!
[*PEGGED* VELOCiTY c was used "measuring" those distances].!!
[Duh.!!]                           brian a m stuckless
  >><> >><> >><> >><> >><>

The Ghost In The Machine wrote:
> Well, this is a bit of a mess...though it's an interesting mess.
> http://www.obs-azur.fr/cerga/laser/laslune/llr.htm
>
> (apparently the site is down at the moment) is an
> observation station in France that among other things has
> been doing laser ranging to the Moon.  I've finally gotten
> around to plotting it and have noticed the following.
> 
> [1] "U"-shapes.   These are obviously from the rotation of the Earth,
>     as they're about 0.01 second high at most and approximately 6 hours
>     wide.  Because the Moon's orbit isn't a perfect circle, they
>     also appear as J's or daubs as well.  Note that 0.01 second
>     is about 3000 km -- just less than half the Earth's radius.
>     I'm assuming the measurements are not as accurate if the Moon
>     is near the horizon as there's rather more atmosphere in
>     the way -- though there are fields in the data for such things
>     as atmospheric pressure and humidity.
> 
>     (Note that in c'=c+v a rotational speed of about 300 m/s
>     will result in a difference of 2.57 microseconds, give or take.)
> 
> [2] The data is rather scanty, though were I to work at it I could
>     probably try to curve-fit it.  There are 6643 data points
>     over the course of about 7 years, but there are long gaps in
>     the graph -- in particular, May 2004 has no observations at all.
>     No doubt one can blame this in part on French weather.  :-)
> 
> [3] The data is showing some odd minima, after discounting [1].
>     In particular, the Mar 15 2000 points are showing a minima
>     around 2.415 seconds; however, data in the Jan 20 timeframe
>     suggests 2.35 seconds, if not even nearer.  Similar things
>     appear to be happening to the Moon's maxima (apogee).
> 
> [4] I could go further with this, as there's plenty of data at
>     ftp://cddis.gsfc.nasa.gov/slr/npt/moon ; they have data
>     dating back to 1969, though I'm not sure I need to go back
>     quite that far and I can't process LLR format anyway.
>     This data has much the same problems as the LaserLune site.
> 
> At least it's raw data I can play with...and presumably others
> can, too;

 insert ..see top of PAGE, dooOP.!!

> -- the format's a bit tricky but not that hard to process.
> But what I can conclude regarding c'=c+v versus SR -- I don't know.
> 
> --
> #191, ewill3@earthlink.net
> It's still legal to go .sigless.