How To Aim Control Points

Tools Needed

• Long Fabric Tape Measure
• Painters Tape
• 1 or 2 Laser levels on a tripod

Measurement Procedure and Point Placement

1. Tape the fabric tape measure to the bottom edge of the screen. Be sure to cover its entire length and note the total measured length of the curve.
2. To find the placement of evenly spaced points, we need to divide the total range into equal intervals. Decide how many points you want to place. The number of spaces between the points is always one less than the total number of points. For Example, if you have 5 points, there are only 4 gaps between them.
3. Divide the total measured length of the curve by the number of gaps. For Example, a length of 10 divided by 4 gaps will give you a spacing of 2.5. Starting at point 0.0 (the bottom-left corner of the screen), visually mark the measured points.
   EXAMPLE 1. 5 POINT MEASUREMENT
   Length of Curve: 10
   Number of Points: 5 (4 Gaps)
   Point Spacing: 10/4 = 2.5
   Point Placement: 0.0, 2.5, 5.0, 7.5, 10.0
   

   Do not measure one section at a time. Each time the tape measure is moved, a compounding error will occur.

    
4. If you only need a top and bottom row of points, place a laser level to line up the marked points at the base of the screen to the top of the screen, and place those points.
5. If you need to find a center row of points, place one laser level and a tripod at the midpoint height. This will be the angular midpoint between the top/bottom angles inputted on the Screens Panel. Place a second laser level and a tripod at the center of the dome's curvature. Accurately finding the center is important.
6. Once the second laser level is centered, rotate it so it is lined up with the points measured at the bottom of the screen. The intersection of the lasers is where the center row of points are aimed.