Short's Telescope

James Short was one of the most prolific telescope makers of the 18th-century. A handwritten instruction sheet, probably by Short himself, accompanies one of his telescopes. His career as an astronomer included many observations of comets, transits of Venus, and the Northern Lights.

This instrument (Image 1) is a small sundial shaped like a ship, made in 1620, probably in England. It tells the time by measuring the angle of the Sun above the horizon, and it can be adjusted for use at any time of year and for places at different latitudes. It would have been very useful for merchants and travellers who had to move around England. In fact, some 15th-century dials like this one have lists of towns and their latitudes on them so that it's even easier to set the instrument ready for use.

James Short was one of the most prolific telescope makers of the 18th-century. A handwritten instruction sheet, probably by Short himself, accompanies one of his telescopes. His career as an astronomer included many observations of comets, transits of Venus, and the Northern Lights.

Handwritten instructions

Accompanying this telescope (Image 1), which is dated 1758, is a handwritten sheet entitled "Directions for James Short'sReflecting Telescope". This is an almost word for word copy of a published instruction sheet, and even incorporates the changes made by Short to his own copy.

The handwriting is similar to Short's, and some details of the copy suggest that he wrote it himself; for example, the instructions for observations have been expanded:

Printed sheet:
"and looking thro' the small Hole in the End of the Eye-piece, if the Image appear[s] distinct it is well"

Handwritten sheet:
"& looking thro' the small Hole in the End of the Eye Piece, you must turn about the Long Rod one Way or the other till you see the Image distinct."

The first quotation is underlined, which suggests that Short wanted to change the brief instruction, and the expansion in the handwritten sheet could well be such an alteration. It is likely that the instructions were handwritten by Short to give to the telescope's owner (Image 2).

The instrument itself is an example of Short's standard reflecting telescope. From his distinctive numbering system we can tell that it was the 958th telescope that he had made.

"...the most remarkable Auroræ Boreales"

Short was educated in both classics and divinity, which was unusual amongst instrument makers of the 18th century, who usually did not attend university. Whilst studying divinity at Edinburgh he attended the lectures of Colin MacLaurin, professor of mathematics; as a result of this encounter he took up astronomy and telescope making. By the age of 24 he was excelling in instrument making, and was soon elected to the Royal Society.

Throughout Short's career he received many important commissions to make instruments, and also carried out many observations. The following, from a 1736 communication by him to the Royal Society, is typical:

"I Came here on Saturday last: That Evening, about Six o'Clock, there was one of the most remarkable Auroræ Boreales that ever I saw. At first there appeared the ordinary luminous Arch ... there appeared little or none of the purple and red Colours which are usually in that Arch; but immediately there broke out, from the most Western Extremity, a great deal of that Northern Light which formed this Arch." (1)