Back to Volume
Paper: The On-The-Fly Imaging Technique
Volume: 217, Imaging at Radio Through Submillimeter Wavelengths
Page: 179
Authors: Mangum, J.; Emerson, D.; Greisen, E.
Abstract: The On The Fly (OTF) observing technique is a well-established and efficient way to obtain images of relatively large astronomical fields. It was used, in fact, for the very first radio-astronomical observations (Jansky 1932) and has been in routine use for spectral-line observations at the NRAO 12-Meter Telescope since April 1994. The primary difficulty in OTF imaging is the very high data rate required to sample the sky properly in an interval shorter than the changes in the instrumental and atmospheric calibration. Hardware limitations at the 12 Meter Telescope lead to a maximum data acquisition rate of 10 samples per second in spectral-line total power observations and 8 samples per second in continuum beam-switched observations (4 per switch setting per second). These data rates appear to be adequate for most imaging experiments at the operational frequencies of the 12 Meter. A number of new programs were added to the AIPS analysis system to support spectral-line OTF data and to implement the Emerson, Klein, and Haslam (1979) algorithm to image beam-switched continuum OTF data.
Back to Volume