Challenge for Mark

[Rocket Pooch]

Get closer to Polaris than this....
IMG_0263 by chrissuddell, on Flickr

[Mac]

you've even managed to photograph the meridian lines

Not quite dead centre though.
and your guiding look a bit off.

Is this a first?
Cant remember seeing any images posted of polaris.

Mac.

ps as im a total fruit cake.
looking at the star trail bottom right and using the small angle calculation.
From polaris the length as measured in photoshop is 20.75 from polaris,
the length of the star trail is 0.46

there are 86400 seconds in a day

1 complete day = 6.283 Rads

so in one day 86400 seconds, the star will travel 6.283 Rads

the angle measured is 0.0221 rads. 
using the small angle calculation.

the angle converted works out to be about 303 seconds.

So i think your exposure is about 5 mins

Just dont ask me that colour your underpants are.

[Mike]

OK, it's official, you REALLY have too much time on your hands.

[Rocket Pooch]

Or you could look at the image properties Exif data and get the same answer nice try Mac.

[Mac]

true you could do that,
but thats no fun.
also your image doesn't have that information attached.

i've just saved your image and checked the exif data, and apart from the size of the image
all the other detail is blank.

Have a check.

Mac.

[Rocket Pooch]

Click on the photo goto action top left and thats where Exif is available

[PhilB]

....also your image doesn't have that information attached...

Ahhhh, so you did look!

[Mac]

didn't do that, just saved the image you posted, which didn't have any.

Ahhhh, so you did look!

only after.

plus the fact your exif is wrong its 303 secs.
Do the maths.

didn't know you could do that in flicker.
Mac.

[Rocket Pooch]

oh no my camera is wrongy!