Next: SLIM: A Program to Simulate the ACS Spectroscopic Modes . ... Previous: On the Fly Bad Pixel Detection for the Chandra X-ray Observatory's Aspect Camera . ... We here present an overview of Celldetect , a source detection program for Chandra. ... Celldetect identifies point sources in the presence of background. ... At each point where a detection is attempted, celldetect uses an appropriately sized cell. ... The background statistics in celldetect change as the cell size increases. ...