TY - JOUR
T1 - On-sky demonstration of precision photometry with Bayer color filter arrays
AU - Gee, Wilfred
AU - Guyon, Olivier
AU - Jovanovic, Nemanja
AU - Schwab, Christian
AU - Coutts, David
AU - Walawender, Josh
AU - Mukherjea, Aru
N1 - Funding Information:
Project PANOPTES was funded in part through NASA’s Universe of Learning (UoL) Program via a subcontract with the Jet Propulsion Laboratory. This material is based upon work supported by NASA under Award Number NNX16AC65A. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Aeronautics and Space Administration. The author would also like to thank the Keck Visiting Scholars Program for funding some of the work related to this manuscript.
Publisher Copyright:
© 2021 Society of Photo-Optical Instrumentation Engineers (SPIE).
PY - 2021/10/1
Y1 - 2021/10/1
N2 - Consumer-level digital single-lens reflex (DSLR) cameras are typically not used in professional astronomy because of the systematic errors present in the data as a result of the strong intra- and interpixel variations associated with each of the three different colors (RGB) of the Bayer color filter array. Nevertheless, because the cost of DSLRs compared with traditional astronomical CCDs is so much lower, they represent a potentially underexplored area of scientific quality astronomical imaging, especially in the area of wide-field transient surveys. We demonstrate an algorithm that can achieve ≈ 1 % level photometry in each of the RGB color channels from a stellar source and discuss the application of this algorithm to a ground-based transiting exoplanet survey. The algorithm primarily takes advantage of the large number of stellar sources available for statistical averaging within a single image, using a "lucky point-spread function"approach to identify sources in the image that exhibit systematic errors consistent with a chosen target from the same image. The selection of the appropriate"lucky"reference stars is accomplished through a comparison of the stellar image morphology as it appears on the Bayer array and the reference stars. These references are linearly combined to form a synthetic comparison star that can be used for differential photometry with the target. One key to the algorithm is that all data are retained at the individual pixel-level until the final differential comparison, which helps to alleviate systematic effects that might otherwise cancel each other out during the flux-summing process. We demonstrate the algorithm on HD 339461, a mV = 8.93 G0-type star on which we achieve single-percent level photometry that approaches the fundamental noise floor possible from a single camera.
AB - Consumer-level digital single-lens reflex (DSLR) cameras are typically not used in professional astronomy because of the systematic errors present in the data as a result of the strong intra- and interpixel variations associated with each of the three different colors (RGB) of the Bayer color filter array. Nevertheless, because the cost of DSLRs compared with traditional astronomical CCDs is so much lower, they represent a potentially underexplored area of scientific quality astronomical imaging, especially in the area of wide-field transient surveys. We demonstrate an algorithm that can achieve ≈ 1 % level photometry in each of the RGB color channels from a stellar source and discuss the application of this algorithm to a ground-based transiting exoplanet survey. The algorithm primarily takes advantage of the large number of stellar sources available for statistical averaging within a single image, using a "lucky point-spread function"approach to identify sources in the image that exhibit systematic errors consistent with a chosen target from the same image. The selection of the appropriate"lucky"reference stars is accomplished through a comparison of the stellar image morphology as it appears on the Bayer array and the reference stars. These references are linearly combined to form a synthetic comparison star that can be used for differential photometry with the target. One key to the algorithm is that all data are retained at the individual pixel-level until the final differential comparison, which helps to alleviate systematic effects that might otherwise cancel each other out during the flux-summing process. We demonstrate the algorithm on HD 339461, a mV = 8.93 G0-type star on which we achieve single-percent level photometry that approaches the fundamental noise floor possible from a single camera.
KW - Bayer
KW - Exoplanet transit
KW - Image processing
KW - Photometry
UR - http://www.scopus.com/inward/record.url?scp=85122616417&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85122616417&partnerID=8YFLogxK
U2 - 10.1117/1.JATIS.7.4.048001
DO - 10.1117/1.JATIS.7.4.048001
M3 - Article
AN - SCOPUS:85122616417
VL - 7
JO - Journal of Astronomical Telescopes, Instruments, and Systems
JF - Journal of Astronomical Telescopes, Instruments, and Systems
SN - 2329-4124
IS - 4
M1 - 048001
ER -