DDM200 user manual - hardware
Created by: MPuchner 01.2020
version: 9600024A
Original user manual
page 21 of 66
printed: 25.02.2020
North-South marking on foundation
This chapter describes how to mark the north-south direction on your concrete foundation.
A very simple and accurate method is to use the sun like on a sundial.
Therefor find out when it is solar noon at your location. At solar noon the sun is exactly on the meridian
(imaginary line between N and S).
This is normally not exactly at 12:00
.
You can look that up on websites like:
https://www.timeanddate.com/sun/
Enter your location and choose the current date in the table and look for Solar Noon - Time.
Another option is to look for the sun position in your planetary software like TheSky, Skychart,…
The marking should be made exactly at solar noon!
Place a plummet at the edge of your concrete foundation. Now the sun throws a shadow onto the concrete
surface. Place the plummet so that the shadow line crosses the center of the pillar (or the desired center of the
telescope base plate). Draw a line along the shadow line.
Figure 13 - make north-south marking
