With Longitude Punk'd now safely open, I thought I'd take a chance to add my congratulations to Matthew Dockrey, who won the competition we ran with his splendid Celatone.


Dockrey Putting the finishing touches to the display in the Royal Observatory

I wasn't involved in the judging, but I was delighted that this entry won, because it absolutely fulfilled our hope that some of the genuine submissions to the Board of Longitude might inspire new artworks. This is how Matthew described his piece:

I have contrived an interpretation of Samuel Parlour’s “apparatus to render a telescope manageable on shipboard” (RGO 14/30: 502-505), which was itself a reinvention of Galileo’s celatone. As the design was already quite fantastical, most of the changes made were in order to fit within the size restriction of the competition. The spyglass is an antique, but all other parts were custom made. As per Parlour’s original design, the finder can be moved side to side, allowing the wearer to position it to match their interocular distance. However, in what I flatter myself is a slight improvement, this is accomplished by means of an adjustment screw which can easily be operated and carefully set while the device is being worn. The candle height is also adjustable, which I found to be particularly useful in properly illuminating the finder when using it at night. Overall, I have endeavored to create an item which feels both functional and fantastic, while honouring Parlour’s design and the technology of the era.

I was also pleased because I've had a bit of a soft spot for Samuel Parlour since first coming across his shoulder-mounted apparatus in the Board of Longitude archive. In fact, it was his device that first made us think of doing Longitude Punk'd.

Parlour Parlour’s apparatus (Cambridge University Library, RGO 14/30, fol. 504)

So here's a bit of the historical background. Parlour's scheme was for observing eclipses of the four largest satellites of Jupiter for determining longitude. Though it was highly successful on land, no-one had yet managed to make this method work at sea, despite various attempts since Galileo first proposed and tried out his celatone in the 1610s. One hundred and fifty years later, Nevil Maskelyne was still able to write in the Nautical Almanac that, 'the great Power requisite in a Telescope for making these Observations well, and the violence as well as Irregularities of the motion of a Ship' presented overwhelming difficulties. This did not prevent people trying, however, and the Board considered proposals for finding longitude from Jupiter's satellites right through to its demise in 1828.

Parlour wrote to the Board in 1824 from the East India Military Seminary in Surrey, enclosing his sketch and description of a device incorporating a telescope with a magnifying power of 80 times. Having tested it at sea between London and Lyme Regis, Parlour believed that it would be steady enough for observing Jupiter’s satellites or the conjunction of the Moon with other stars, ‘even in a rough sea, and heavy swell’. These were grand claims, but the Board took Parlour's ideas seriously enough to organise a sea trial the following year. Sadly, the resulting report found that the apparatus was too difficult to manage:

From the very great length of the telescope & the frame, I invariably found that the wind affected it so much, it was impossible to keep it fixed for more than a second at a time upon a star… I also found much inconvenience in keeping it on my shoulders for more than a minute or two at a time, in consequence of its very great weight.

although the report did suggest that it might be useful on larger, less lively ships. Nonetheless, it doesn't seem that there were any further developments.