Radius and Sag Calculations              
     
     
Spherometer Ball diameter mm    
  Distance from ball to gauge mm (or semi-diameter)    
     
Calculate sag Radius of optic mm (enter negative number for concave radius)  
  Sagitta - convex mm inches    
           
     
     
     
     
 
     
     
     
     
     
Graph is for reference only, in an actual spherometer there are 3 balls spaced at 120 degrees.  
     
 
 
Calculate radius Sagitta mm 0.01243 inches  
  Radius of optic -convex mm      
           
 
 
 
 
 
 
 
 
 
 
 
Graph is for reference only, in an actual spherometer there are 3 balls spaced at 120 degrees.