Comet Wirtanen


Dr. Roemer was well known for her prolific "recoveries" of known short period comets (comets that take less than ~20 years to go around the Sun). Unlike today where many short period comets can be followed all the way around the Sun, in the past these comets would be lost once they got too far away. Dr. Roemer would "recover" these comets as they made their way back towards the Sun by searching the area where they were predicted to be, looking for a faint dot moving ever so slightly relative to the background stars. This was often a quite challenging task since it is difficult to predict exactly where or how bright a comet will be, and the longer it has been since a comet was last seen, the harder the task becomes. Without Dr. Roemer's work, many comets may have been lost for decades; her measurements of their brightnesses at large distances are still used by astronomers today.