SO Colloquia: Searching extended line-emission objects in wide-field surveys: The IPHAS experience

One of the problems we are facing in the study of evolved low- and intermediate-mass stars such as Planetary Nebulae (PNe) is the lack of completeness. Most known PNe belong to the bright or intermediate part of the luminosity function, leaving out those at the faint end. Any global chemical, kinematical, and physical analysis of the PN population is therefore biased. In 2003 the INT Photometric Halpha Survey started scanning the Galactic Plane to look for new emission-line objects of all sort among which new PNe. I have been working on the detection of new low surface-brightness extended nebulae using a mosaicking technique. Various new symbiotic stars, supernova remnants and PNe that had escaped earlier screening were then discovered. I will present the characteristic of IPHAS and the detection methods that were used and how this experience can be used by other imaging and photometric surveys.