Asteroid Day

30 June 2018

On August 18th 1783 an unusually bright meteor was observed streaking through the sky. It entered the Earth’s atmosphere over the North Sea before passing over the east coast of Scotland and England before breaking up over South West France and Northern Italy.

There were many witnesses to this astonishing event but perhaps the most significant was the group of men who observed this interstellar phenomenon from the terrace at Windsor Castle. This group included Dr Lind, Mr Cavello, an Italian natural philosopher, Dr Lockman and Mr T. Sandby, brother to the artist Paul Sandby. Their account, a version of which can be found in the Mount Stuart archive, was endorsed by the 3rd Earl of Bute and is probably the most accurate but by no means lacking in awe.

Read the full account transcribed below:

Description of a meteor observ’d from Windsor Castle Aug. 18th 1783.

Being upon the Castle Terrace at Windsor, we* observ’d a very extraordinary Meteor in the sky, such as none of us had seen before. We stood upon the N.E corner of the terrace, so that we had a perfect view of the whole phenomenon, & as everyone of the company remark’d some particular circumstance, the collection of all which furnished the materials for this account, it is presumed that the Description is as true as the nature of the subject can admit of.

The weather was calm & arguably warm & the sky was serene excepting very near the horizon, where an hazyness just prevented the appearance of the stars. A narrow ragged and oblong cloud stood in the N.E. side of the heavens, reaching from the extremity of the hazyness which rose as high as 18 or 20 degrees, in a direction nearly parallel to the horizon.

It was a little before this cloud & consequently in the hazy part of the atmosphere, about the N. by W. 1/12 W. point of the compass that this luminous meteor was first perceiv’d. some flashes of ambient light much like the Aurora Borealis , were first observ’d in the northern part of the heavens which were soon perseiv’d to proceed from a round luminous body as big as the semi-diameter of the Moon & almost stationary in the above mentioned part of the heavens.

It was about 20 minutes after 9 o clock in the Evening.

This ball at the beginning appeared a faint bluish light perhaps from its being just kindled or its appearance in thro’ the hazyness, but it gradually increas’d its light & soon began to move, at first ascending above the horizon in an oblique direction towards the East. Its course in this direction was very short, perhaps 5 or 6 degrees, after which it turn’d itself towards the East & moving in a direction nearly parallel to the horizon, reach’d it as far as S.E by E. where it finally disappeared.

The whole duration of the meteor was half a minute or rather less & the altitude of its track seemed to be about 25 degrees above the horizon. A short time after the beginning of its motion the luminous body passed behind the aforementioned cloud so that during this passage, we observ’d only the light that was cast in the heavens behind the cloud, without actually seeing the body from which it proceeded for about the 6th or at most the 5th part of its track, but as soon as the meteor emerged from behind the cloud, its light was prodigious, every object appeared very distinct, the whole face of the country in that beautiful prospect before the terrace being instantly illuminated.

At this moment the body of the meteor appear’d of an oblong form but it suddenly acquired a tail & soon after it parted into several small bodies, each having a tail, & all moving in the same direction at a small distance from each other, & very little behind the primary body, the size of which was gradually reduc’d after the divisions. In this form the whole meteor mov’d as far as the S.E. by E. where – the light decreasing rather abruptly the whole – meteor disappeared. –

*Dr Lind, Mr Cavello, Dr Lockman, Mr Sandby