1. A computer-implemented method for determining celestial coordinates corresponding to an image, comprising: receiving an image comprising a plurality of depicted objects; generating, at a processor, a list of initial coordinates indicating positions, with respect to an origin point for the image, of a plurality of depicted objects in the image; selecting, at the processor, a group of objects from the plurality of depicted objects; generating, at the processor, a test signature based on the initial coordinates of the objects in the selected group; searching a data store for at least one reference signature that matches the generated test signature within a specified tolerance; for at least one reference signature that matches the generated test signature within a specified tolerance: obtaining a celestial position corresponding to the reference signature; determining, from the obtained celestial position corresponding to the reference signature, celestial coordinates for the image; and outputting the determined celestial coordinates at an output device; wherein searching a data store for at least one reference signature that matches the generated test signature within a specified tolerance comprises: for at least a plurality of reference signatures in the data store, performing an affine fit operation to generate a geometric transform representing the relationship between the generated test signature and the reference signature; and identifying at least one reference signature for which the generated geometric transform indicates that the reference signature matches the generated test signature within a specified tolerance.