Astrometry is the precise measurement of the position of celestial objects, such as stars, minor planets (asteroids), supernovae, and comets. In the case of new discoveries, this can be extremely important for orbit determination and for planning follow-up observations. The determination of an accurate orbit for a new object requires multiple precise positions over a period of time. Until the advent of CCD cameras and analysis software, this was a time-consuming and difficult procedure. Now highly accurate measurements can be made quickly and easily.
For performing astrometric measurements, MaxIm DL includes the PinPoint LE Astrometric Engine from DC3 Dreams, SP (http://pinpoint.dc3.com), which integrates seamlessly with MaxIm DL. (Additional capabilities are available with the full version of PinPoint, which is also compatible with MaxIm DL.)
Once PinPoint is set up for the star catalog and the general characteristics of your images (rough image scale, etc.), the analysis is fully automatic. When using the Camera Control and Observatory Control windows, a rough position is added to the FITS header for each image. PinPoint uses this as a starting point. It finds all the stars in the image, matches against catalog positions for stars in that vicinity, and then calculates a mapping between the catalog and the image.
This mapping is stored as World Coordinate System (WCS) values in the FITS header of the image. This WCS header information is standardized, so it is compatible with many other software applications.
Once the WCS information is available, MaxIm DL can provide precise measurements of the position of any object in the image, using the Information window. Under typical observing conditions, the measurements are often accurate and repeatable to a fraction of an arc-second.
For full details on performing astrometric solves in MaxIm DL please see PinPoint Astrometry.