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And what time is it at Greenwich? In the photo of Richard Dunn here: http://www.mysticseaport.org/event/longitude-found/?enews,
can you determine GMT from the details of the photo? He is standing more or less on the Prime Meridian in the photo, so that helps. From other visual clues, can you determine the time (GMT) when this photo was taken?  Big hint: it's a trick question. :)  Frank Reed

It’s a bit mean giving us a low definition photo Frank.  If it was high definition, we could read the time on Richards’s wristwatch.  However, that might not be dependable, because from the foliage on the trees, British Summer Time (GMT + 1) must be in operation.  It’s interesting though that the guardian of so many ancient analogue timepieces wears a digital wristwatch.  That brings us to shadows.  We must treat near shadows with caution, because this looks like a posed publicity photo and professional photographers often use floodlights, so we need to look at distant shadows.  The photographer appears to be in line with the eastern wing of the Queen’s House complex, so must be pointing about 350True.  Richard is probably at work between about 8.00AM and 5PM BST, and it’s warm enough for him to be in shirtsleeves.  However, there appear to be very few, if any, tourists in the park, so it must be fairly early.  Greenwich Park opening times are 6AM to around 9PM in the summer, so that doesn’t help much.  The Sun is in the south east sector, so it’s clearly morning.  We just have to try and measure some shadow angles and lengths.  The west corner of the east wing of the Queens House complex gives a good angle. It lies about 2 arches in from the end.  I would put it at about 315(T).  That would make it about 09.00GMT, 10.00BST possibly slightly earlier because of the lack of tourists.  Now someone is going to say, if you look and listen carefully, you can just see a church clock reading 10.00 and hear it chiming ten.  DaveP