what is cross correlation used for how to measure pixel offset how to measure lag how to measure lag if the spectral offset is a subpixel is that is accurate why do we use cross correlation what is the best way to measure the lag? how to measure pixel offsets how do cross correlations work what is cross correlation in astrophysics how to measure the lag of a data set what is cross correlation used for? can you measure a subpixel shift? how do we measure the difference in the lag what is the correct way to measure lag how to measure lag what is the measure of lag what is the correct measure of cross correlation how do you measure a lag on an image how does cross-correlation work