theodolite

[thundercrack]

hi, can anyone tell me where I can get idiots instructions on how to use a theodolite? or does someone know how?
thanks, alf.

[sddsddean]

I know how to do it, but I've found this site which should help with the basics.
http://www.civl.port.ac.uk/projects/survey/the oinfo.htm
Remember to take your time setting it up, as time spent here will save a lot of head scratching later. Need any more advice, then re post here.

[thundercrack]

thanks sddsddean, good info, will be trying to level a site on saturday as a practise, so will no doubt be in touch saturday evening. I have also bought a laser level, so will be able to check accuracy at night fall. ( I hope)
thanks again, alf.

[sddsddean]

If you are using a theo to level a site, it is abit of overkill. A dumpy level or automatic level would be more appropriate. However, if this is just practise don't forget to lock the theo vertical circle at 90 degrees so that it will act as a circle. Try practising taking horizontal angles. I was always taught to take 4 readings to a point.
1) Set angle and read
2) Knock off micrometer and reset and read
3) Knock off micrometer and horizontal lock. Re aim, reset and read
4) knock off micrometer and read

Your actual horizontal angle reading would be the average of these 4 readings. If you 'aim' at something a mile or 2 away (say a tower or something) you will see how over distance the readings can change. Good luck. No doubt be hearing from you Saturday!!

[thundercrack]

hi sddsddean, theo did not arrive til yesterday. with your info and the japanese written instructions I managed to find a level, I used next doors damp course as a datum mark. we then confirmed measurement with a laser leveller ( borrowed it from a builder ) and checked our first measurement was correct. the laser is much easier to use, but is very restricted in distance and can't verify right angles. the theo /dumpy is an excellent piece of kit and the accuracy is millimetres over a kilometre, whereas the laser is 2.5mm out over 15 mtrs.
thanks for the advice
regards, alf.