Comet Time Series (CometTS) is an open-source tool that facilitates analysis and visualization of satellite imagery time series. Such analysis can enable population estimation research, change detection methods, or natural disaster monitoring. Historically, analyzing large time series of satellite imagery was achieved using proprietary GIS tools or by time-intensive methods requiring substantial geospatial expertise. CometTS requires only a web browser, Python, and dependent packages to function, obviating the GIS requirement for time series analysis and visualization. CometTS provides a partially automated approach for analyzing a time series of satellite imagery in any user defined area of interest, then calculating relevant statistical quantities (e.g., measures of central tendency and variation), and visualizing their changes over time, all in a matter of seconds. The overall focus of this talk will be on the development and application of CometTS for two analyses: 1) analyzing dynamic population changes over time in Africa and the Middle East and 2) ccreating the first independent estimate of the number of persons without power over time in Puerto Rico following Hurricane Maria.