BNG to LatLong

If you need a latitude and longitude of your observing location for your favourite astronomical software, then this applet is your answer. By entering a 6 figure easting and northing taken from any Ordnance Survey map, you will be given a latitude and longitude to the nearest second (about 100m).

For example, if you've got Landranger Map 175 handy check out this example. St. Peter's Church Hall can be found at grid reference 474500, 172100. Look it up for yourself, you need all six digits including the first one which can be found in the corners of the map as the small superscript numbers. On map 175 the SW corner is labelled ⁴60^000m and ¹55^000m. Try The Church Hall in the applet and you should get Latitude = 51°26'33"N and Longitude = 0°55'41"W.

This Java applet was written by Keith Adlam, Jeremy Giles and John Talbot of the British Geological Survey and used with kind permission.

GraphDark

Written by RAS member Richard Fleet, this software tool is invaluable for finding out when an astronomical object will be visible from your location and when moonlight, twilight or low haze will affect its visibility. You can find out all about the software at Richard Fleet's pages.

Download GraphDark (v2.04)