Estimation of the Accuracy of Measuring the Position of A Stellar Image by Means of An Array Device

When an array device such as a CCD, Reticon, etc. is used to observe a star, the gravity center of luminosity of the image of the star can be found as the center of the image by means of the information provided by the luminosity readings of the pixels. The estimation of the accuracy of measuring the position of a stellar image by making use of the gravity center method is expounded in this present article by applying the knowledge of probability and mathematical statistics. And a conclusion is drawn from the exposition that the accuracy of the measurement is inversely proportional to the square root of the overall luminosity readings of the pixels of the stellar image.