The Camera Obscura on Castle Hill is well worth a visit. The camera itself was originally installed on the roof by Maria Theresa Short in 1852. Although the rest of the building has gone through a number of uses since, the camera is still there and the remaining floors have been given over to a museum of science and illusions. It is great fun and most illuminating, but you would not want to visit on a full Scottish or Irish breakfast. You have been warned.

Let's go in and have a look. Just in time to check out the roof and then go in to the 11am demonstration of the Camera Obscura itself.

This is the Camera from the outside. As you may be aware, the original camera way back was called a camera obscura, or simply a dark room. Then it had a pinhole in one wall and the scene outside was projected onto the opposite wall. This was all in real time and there was no question of any film being involved.

This is precisely what the current camera obscura is, except instead of being horizontal it is vertical with the pinhole pointing towards the sky and the image projected on the floor/table inside.

Now a point in the sky would be of limited interest so this particular camera obscura has a 45 degree mirror fitted outside and above the pinhole, so that what you actually see is a panoramic view of Edinburgh. The mirror can be rotated and the angle adjusted from inside the room so that you can actually see everywhere that is visible from the roof itself, and a little more.

With a little practise, you can change the focal length of the lens, isolate parts of the picture, and play tricks on the people below.The presentation is structured to give you a ten minute live tour of Edinburgh which you can then follow up when you leave the premises. It is exquisitely presented and very well thought through.

I couldn't take a photo of the projected images as the room has to be in complete darkness and the image is faint enough.

The picture above shows you the structure of the top of the camera with the 45 degree mirror. There are also four CCTV cameras mounted at four points round the camera and you can manipulate these yourself later on from inside the museum.

This shows two of the CCTV monitors. The top one is looking down the Royal Mile with the Hub/Fringe HQ on the right. The bottom one is looking back at the castle and shows part of the huge stand which is built for the Tattoo each year and is currently in the course of being dismantled.

You can manipulate these cameras yourself, swing left and right, up and down, and zoom in on your target. It's great fun. You are warned, however, not to invade peoples privacy.

This is a heat map and I am taking my first ever heat selfie. The contrast between the individuals in the room is interesting though I haven't the faintest idea what it means.

This is another selfie in the distorting mirror, though I have to admit the degree of distortion is minimal. Or so my "friends" tell me.

Finally, Salom� and John the Baptist. I say finally because I have to stop somewhere or we'd be here all night. Anyway the message is clear. If you're ever in Edinburgh don't miss visiting this wonder of wonders.



And for those oldies who have retained their sense of wonder but are nonetheless curious, and for the young ones whose sense of magic leads them to be curious, here are the technical details of this wonderful machine.