AAVSO: American Association of Variable Star Observers

Photometric Accuracy of CMOS and CCD Cameras (Preliminary Results) (Abstract)

Volume 47 number 2 (2019)

Kenneth T. Menzies
318A Potter Road, Framingham, MA 01701; kenmenstar@gmail.com


(Abstract only) Photometrists regularly ask the question as to how accurate their magnitudes are. Methods are described that will help you evaluate your accuracy by imaging standard fields in multiple filters, using vphot to conduct photometry, and using excel/pivot tables to reduce the data and compare the accuracy of measured magnitudes compared across different cameras and compared to Landolt Standards (SA101). Specific examples of data from BSM cameras, including a CMOS camera and three CCD cameras, are compared. Based on preliminary results, it has been determined that: (1) Landolt standard fields provide effective analysis of accuracy of photometric systems;, (2) vphot and excel/pivot table tools facilitate analysis; (3) Differences between CMOS and CCD camera magnitudes are negligible / within experimental error (if SNR > 50); (4) Differences between known and measured magnitudes are negligible / within experimental error (if SNR>50); and (5) As expected, selection of proper comp SNR and photometric aperture, as well as image quality, impacts experimental error and bias.