Advanced exposure-time calculations: Undersampling, dithering, cosmic rays, astrometry, and ellipticities

The familiar tools of Fourier analysis and Fisher matrices are applied to derive the uncertainties on photometric, astrometric, and weak-lensing measurements of stars and galaxies in real astronomical images. Many effects or functions that are ignored in basic exposure-time calculators can be included in this framework: pixels of size comparable to the stellar image, undersampled and dithered exposures, cosmic-ray hits, intrapixel sensitivity variations, and positional and ellipticity errors, as well as photometric errors. I present a formalism and a C++ implementation of these methods. As examples of their use, I answer some commonly arising questions about imaging strategies: What amount of dithering is ideal? What pixel size optimizes the productivity of a camera? Which is more efficient-space-based or ground-based observing?