|Title:||A New Approach for Wide Field Time Series Photometry: applications for variable stars and asteroids|
|Speaker:||Prof. Yong-Ik Byun (Yonsei University, Seoul, South Korea)|
|Date:||Thursday, 21 April 2016|
|Time:||11:00 - 12:00|
Early work with YSTAR 0.5m wide field telescopes revealed the presence of variable photmetric trends within the FOV of 2 degrees. Experiments with other wide field survey data also confirmed such trends. We developed a robust and efficient approach to make multi-aperture photometry and remove existing trends for wide field time series observations. The merit of this approach is as follows: we find an optimal aperture for each star with a maximum signal-to-noise ratio and also treat peculiar situations where photometry returns misleading information with a more optimal photometric index. We also adopt photometric de-trending based on a hierarchical clustering method, which is a very useful tool in removing systematics from light curves. Our method removes systematic variations that are shared by light curves of nearby stars, while true variabilities are preserved. I will outline the procedure and examples of new scientific results obtained by this improved procedure, together with our current work with KMTNet observations.