Home Made Transit

If you have a small video tripod with a center post or removable head you can convert in into a simple transit to make sun azimuth / direction and elevation / altitude measurements. You need a 360 degree 4" diameter protractor and a 4" plastic lid from a coffee or other can. Measure carefully the center of the lid and cut a hole to fit the center post or bolt between the tripod and head. The bolts between the head and tripod are usually 3/8". Carefully cut the center out of the protractor so it will freely rotate within the plastic lid. A coping saw and vice will make cutting the circular protractor easier. Hold the protractor close to the cut. You only need the outside ¾" of plastic. Attach a pointer to the base of the tripod head to point at the numbers on the protractor as you pan the head. This is your azimuth scale. Black out any unused scales. You want the 0 to 360 degree scale moving clockwise as you pan right.

You can attach a clinometer, Abney Level or angle finder (hardware stores, the bigger the better, remove the magnets) to the top of the tripod head to check the altitude / height of the sun. You will need a 90 degree bent shelf bracket and a ¼-20 nut to attach the shelf bracket to the camera screw or quick release shoe. Tape or Velcro the clinometer or angle finder to the shelf bracket so that when the head is level a finder edge is level and reads 0 degrees and as you tilt up it increases toward 90 degrees which is straight up. (The angle finder might be up-side down.) Don't trust a magnetic compass around the steel bracket and other parts of the tripod that might effect it

Azimuth Protractor on Bogan Head

Angle Finder to Measure Elevation

Suunto Tandum

The angle finder or clinometer is your elevation scale and the pointer and protractor your azimuth scale. Be sure to level the tripod. Point the angle finder/clinometer in a known direction and adjust the protractor opposite that known direction. Now the transit is aligned to true north.

© Copyright 1999-2004 Ron Dexter. All Rights Reserved.