For orientation of a plane table with three points A, B and C, Bessel's drill is

• Align b through a and draw a ray towards c, align a through b and draw a ray towards c, finally align c through the point of intersection of the previously drawn rays
• Align c through a and draw a ray towards b, align a through c and draw a ray towards b, finally align b through the point of intersection of the previously drawn rays
• Align c through b and draw a ray towards a, align b through c and draw a ray towards a, finally align a, through the point of intersection of the previously, drawn rays
• In the first two steps any two of the points may be used and a ray drawn towards the third point, which is sighted through the point of intersection of previously drawn rays in the final step.