Scanning strategies for imaging arrays

摘要

Large-format (sub)millimeter wavelength imaging arrays are best operated in scanning observing modes ratherthan traditional position-switched (chopped) modes. The choice of observing mode is critical for isolating sourcesignals from various types of noise interference, especially for ground-based instrumentation operating undera bright atmosphere. Ideal observing strategies can combat 1/f noise, resist instrumental defects, sensitivelyrecover emission on large scales, and provide an even field coverage – all under feasible requirements of telescopemovement. This work aims to guide the design of observing patterns that maximize scientific returns. Italso compares some of the popular choices of observing modes for (sub)millimeter imaging, such as random,Lissajous, billiard, spiral, On-The-Fly (OTF), DREAM, chopped and stare patterns. Many of the conclusionsare also applicable other imaging applications and imaging in one dimension (e.g. spectroscopic observations).