The Green Ray (back blip for Tue)

Where I live in Leytonstone is just a few miles north of Greenwich. This means that when atmospheric conditions are right, I can see the green laser projected due north from the Royal Observatory to mark the Prime Meridian, zero degrees of longitude.

The laser was switched on in 1999 for the milennium celebrations and is here seen from the Cathall Road bridge over the A12. Although it looks as though it rises into the sky at around 45 degrees, that's an illusion caused by the fact that the beam barely spreads out; it's actually near-horizontal as it passes over.