On Tue, Apr 4, 2017 at 11:07 AM, Derick Rethans <tz@derickrethans.nl> wrote:

On Tue, 4 Apr 2017, Randal L. Schwartz wrote:

> >>>>> "John" == John Haxby <john.haxby@oracle.com> writes:
>
> John> (If you're ever near Greenwich I recommend visiting the Royal
> John> Observatory, taking the obligatory foot-in-both-hemispheres selfie
> John> and then going to look at the clocks.)
>
> And you should also note that the location where they charge you to take
> that photograph is about 20 meters to the west of where it should be.
> At least, I presume my modern smartphone's GPS is fairly accurate, as
> well as having looked it up on Google Earth later.

I always thought that the meridian line as marked is 0° in *OSGB36*, not
WGS84 which is what GPS uses:

http://theconversation.com/heres-why-the-greenwich-prime-meridian-is-actually-in-the-wrong-place-46302
http://metro.co.uk/2015/08/15/oops-the-greenwich-meridian-line-is-in-the-wrong-place-5344251/

George Kaplan and his colleagues went into why the "Greenwich Meridian" moved pretty exhaustively. 

https://www.researchgate.net/publication/282478531_Why_the_Greenwich_meridian_moved

Regards

Marshall Eubanks 

 

cheers,
Derick