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Surveying Gear

Starting off around 1990 with a Kern GK0 tilting level found at a camera fair, and bought simply because I liked the look of it, I gradually amassed a range of instruments. Most of these were associated with my hobby interest in surveying stone circles. I've listed the tripods as each one is different to the others, and whilst the two Hilger & Watts tripods have the same fitting, they are of a different style and height. The only tripod with what's considered to be the modern standard top is that bought with the T2 theodolite from a surveying instrument service and hire company.

Levels

Theodolites

Height Staffs

Targets

Tapes

EDMs

Subtense Bars

Prisms

  Sextant

  GPS

Background

My background is physics and military avionic/electronic engineering. In addition to my enduring interest in photography, I’ve had two quite serious hobby interests over the last decade. (The other is sound recording)

Millimetre Accurate surveys of Stone Circles – 1993-2000

I already knew from Professor Thom’s book (Megalithic Stone Circles) about his theories that stone circles were quite accurately laid out, and had astronomical significance – particularly in parts of Scotland, when I came across two books (both by eminent academics) showing significantly different plans of the layout of the stones at the Druid’s Circle, Penmaenmawr. The main stone in question weighed several tons and so was unlikely to have been moved by a bunch of chavs after a night out, but was shown lying differently in the two books. As common in academia, other books followed one or other of these two, and more worryingly, drew conclusions from what was obviously incorrect data! I also knew that very many academics in this field did not have any scientific or engineering training, so I set about trying to do accurate surveys of accessible stone circles. I hoped eventually to publish my plans. Whilst I had an engineering degree, it hadn’t covered surveying so I took a course at Oxford University which was part of their post-grad syllabus for archaeologists. On this course I learnt just how expensive modern surveying equipment was – it made photography look like a cheap hobby!

After some searching I bought a used classic theodolite, a Wild T2 (with care, this can measure to 1” of arc) and tripod, and one of the first laser Distos. The idea of trying to measure distances accurately over bumpy & tufted grass using a tape was not attractive when a laser beam could do it to +/- 2mm over distances up to ~ 100m. I then devised a method of mounting the Disto on the top of the theodolite’s telescope so that I could measure distances along the line of sight. I taught myself basic database theory, CAD and basic programming so that I could record angles and distances, reduce these to a level plane, plot and print my results. I used the first version of MS Access as soon as it was available for recording and reducing my results.

With the help of my partner and youngest daughter (on separate occasions) we surveyed Kerry Circle in mid-Wales, and Cerrig Pryfaid in Snowdonia. My survey of the stone circle at Kerry was submitted as my thesis on another short course at Oxford. Using analysis tools in CAD, my survey of Kerry Circle suggests that the central stone was placed, relative to other major stones, to an accuracy of 6mm, but who knows?

So why didn’t I continue?

Unfortunately, the lecturer at Oxford who had inspired me with his course on Stone Circles, Dr Dick Spicer, died early from adult leukaemia, and academic archaeology was moving to different areas, so had little need for accurate surveys of the traditional type. And if they did… - I was also attending the annual exhibitions for the professional surveying fraternity, and I was amazed at how quickly development was taking place in laser based “cloud point” survey equipment. See PointCloud website - How it's done

Whilst even more expensive than other survey gear, this was ideally suited to surveying several stone circles in a day being flown by helicopter from site to site.

So I now have several idle classic theodolites, tripods, levels, laser Disto, etc. with nowhere to go!