Mystery object seen in sky over UK on Saturday 22 Sep 2012

[ikjoyce]

(previously posted in general discussion by mistake - sorry!)

Hi all,

I was out walking in a nature reserve near Coalville, UK on Saturday afternoon with a friend and he spotted something very bright moving rapidly overhead from East to West.
It took me a few seconds to see it, but luckily I had the 400mm lens on the camera, and managed to fire off two rapid shots before I lost it in the glare of the sun.
The weather was very interesting - I had planned on taking photos of birds but got distracted by sun-dogs, and a circum-zenithal arc (also got pictures of these!).
That was why we were looking up so much, and had we not been, I doubt we would have seen this. It had crossed the whole sky in about 8 seconds.

The two shots were taken at about 15:56 GMT (16:56 BST).

Cropped images here:

IMG_9306_Image1
http://www.flickr.com/photos/ikjoyce/
Copyright: Ian Joyce

Click to view full size image

IMG_9305_Image2
http://www.flickr.com/photos/ikjoyce/
Copyright: Ian Joyce

Click to view full size image

First thought was ISS, but that was ruled out very quickly by the time of day, direction of travel, and by looking at the photos!

I have had suggestions from a few people that it looks like a couple of dandelion seeds, which it does so I felt I needed to rule that out.

I sadly have no means of working out how far away the object was, but I can at least use the field of view to get an idea of roughly what size an object would need to be to appear that size on my camera's sensor.

The photos were taken with a 400mm lens on a Canon 600D (which has a 1.6x crop-factor sensor). The full-frame images are 5184 pixels in the horizontal axis. The object covers 100 pixels in the same axis.

Checking online, and also confirming by taking a photo of a tape measure under controlled conditions because I am like that, the FOV is around 3 degrees. (3.194 according to the internet, 2.92 according to my rough calculation)

Using simple trigonometry, a few dandelion seeds stuck together at about 2 cm wide would have to have been about 20 metres away to cover that area of the camera's sensor.

What we saw was definitely a LOT further away than that. It was also far brighter than any dandelion would ever appear without the aid of accellerant and matches.

At 1000 metres away, the object would be about 1m wide.
At 10,000 metres (airliner cruising altitude), it would be about 10m wide.
That's about the size of a London bus, and as far as I know, the route 207 to Uxbridge does not go via the troposphere.

At the top of the stratosphere, 50,000 metres above, the object would have to be around 50 metres wide.

Does anyone have any idea what this could be, given the details above?

In the early hours of Saturday morning, a fireball had been recorded over Northern UK, moving East to West. Could this be related to that, or is it something more mundane?

Any help is much appreciated.

Kind regards,
Ian

[Rothkko]

Click to play embedded YouTube video.

http://www.universetoday.com/97507/fire ... on-friday/