The differencing or subtraction of images is a way of finding all of the photometric changes between two images. This can be used to find or characterize objects that are either variable in nature or that are moving. Performing a simplistic subtraction of one image from another seldom works well at all. Subtle changes in focus and the position of the field of view on the detector are enough to fill the results with a myriad of false detections. What is needed is a way to match the optical and sampling differences between the two images. Steve will give an overview of how this is done and display some results of high quality subtractions. Subtractions are commonly used to identify or characterize asteroids, exo-planets, supernovae, AGNs, light echoes, and just about anything else that changes intensity or position on human time scales in the night sky.
Steve Hartung is a recovering electrical and software engineer. After many years working in industry, he returned to graduate school and received a Ph.D. in computational astronomy where he broke ground in the acceleration of image subtraction using massively parallel processing. He is a developer of pipeline software for the International Astronomical Search Collaboration (IASC), and was previously a collaborator in the International Center for Computational Science (ICCS) based at the University of California at Berkeley Space Sciences Lab (SSL) and the Lawrence Berkeley National Lab (LBNL) National Energy Research Scientific Computing Center (NERSC). Steve is also the current president of the Boulder Astronomy & Space Society.
The meeting will be at the IHOP Restaurant, 2040 Ken Pratt Boulevard, Longmont. Please join us for coffee, dinner, or just desert around 6 pm; The general meeting and presentation will begin at 7 pm.