Angle comparison using an autocollimator

Results of a bilateral key comparison between PTB and METAS on the calibration of an autocollimator are reported. Due to a technical problem, METAS had to withdraw measurement results from the preceding key comparison EURAMET.L-K3.2009, therefore a bilateral follow-up comparison based the same protocol using the same type of instrument was carried out. PTB provided the autocollimator, made stability measurements, collected the results and made a first analysis. METAS drafted the technical protocol, analysed the results and wrote the report. PTB provides the link to the preceding comparison. In this regard PTB's results are considered as reference results, in particular since it declares considerably smaller uncertainties than METAS and its results were consistent with the key comparison reference values of EURAMET.LK3.2009. The measurements included the range of ±1000" in steps of 10" and ±10" in steps of 0.1". The results for the smaller range were entirely satisfactory, the results of the larger range were mostly satisfactory but showed some not yet explained instabilities of the METAS measurements. KEY WORDS FOR SEARCH Angle calibration, autocollimator Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).