A spherometer is often used to precisely measure the radius of curvature of a spherical surface. It can also measure the vertex radius of a more complex surface such as an off-axis parabola (OAP). This paper provides a reliable algorithm to find the vertex radius of an OAP by solving a few equations based on the test geometry. This algorithm can also be easily expanded to any conic surface with high-order aspheric coefficients. The algorithm was verified by measuring an 8-inch diameter OAP and comparing the results with its known prescription. Results show good agreement. An example of measuring the vertex radius of a 4-m diameter OAP is also presented. In addition to this, a calculation was done to show that the coma and astigmatism are independent of the clocking of the spherometer on the optic. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/623276 |
| Date | 23 December 2016 |
| Creators | Dominguez, Margaret Z., Li, Jianxin, Zhou, Ping, Burge, James H. |
| Contributors | Univ Arizona, Coll Opt Sci, University of Arizona, College of Optical Sciences, 1630 East University Boulevard, Tucson, Arizona 85721, United States, Nanjing University of Science and Technology, School of Electronics and Optical Engineering, Nanjing Shi, Jiangsu Sheng 210014, China, University of Arizona, College of Optical Sciences, 1630 East University Boulevard, Tucson, Arizona 85721, United States, University of Arizona, College of Optical Sciences, 1630 East University Boulevard, Tucson, Arizona 85721, United States |
| Publisher | SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | © 2016 Society of Photo-Optical Instrumentation Engineers |
| Relation | http://opticalengineering.spiedigitallibrary.org/article.aspx?doi=10.1117/1.OE.55.12.124107 |
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