The planned Force the Level measurements did not take place on March 9th and 10th due to concerns regarding the weather. The observation site is at 5431 ft (1655m) elevation near Denver, Colorado, US. Many locations at 39° north are saying goodbye to sub freezing temperature but the higher altitude has lower temperatures for the latitude at any time of the year.
Trying to get excellent measurements for 10 hours a day in sub freezing temperatures would most likely waste our window of opportunity. Therefore FECORE has decided to postpone the Force the Level measurements until May 2019.
The greatest effort now is to be sure that the procedure of the readings and the calculations of the data will accurately answer our objective of testing the shape of the geoid in this location.
The observation as currently planned will require readings of rods at 83 different locations. 83 spikes have been placed in a nearly straight line 40 meters apart. That makes the total length 3.28 km or 2 miles. There are 4 rods which will be held plumb by a tripod over the spike locations. The rods will be set in a group of 4. The first of the 4 locations is designated as rod A1 and then B1, C1 and D1. The DAL (digital auto level) is placed between rods A and B. The placement of the DAL between A and B is designated as Position 1. Readings of all 4 rods are made from this position. The DAL is then moved between rods C and D designated Position 3 and readings are taken. Lastly the DAL is moved between B and C to Position 2 and readings are taken.
Each rod location is 40 meters apart. After the readings at Position 2 the rod at location A1 will then be moved past the other three rods to the next location down the line. This makes the rod B1 now the A2 rod so this is the 4 rod group number 2, A2 thru D2.
The many hours of effort by the principle researchers on this project is greatly appreciated.
The weather observation equipment has it’s own cart so refraction effects can be accurately calculated for each reading.