Pointing effects and their consequences for Spitzer IRAC exoplanet observations

Spitzer observations of exoplanets routinely yield accuracies of better than one part in 10,000. However, there remain a number of issues that limit the attainable precision, particularly for long duration observations. These include initial pointing inaccuracies, pointing wobble, initial target drift, long-term pointing drifts, and low and high frequency jitter. Coupled with small scale, intrapixel sensitivity variations, all of these pointing issues have the potential to produce significant, correlated photometric noise. We examine each of these issues in turn, discussing their suspected causes and consequences, and describing possible and planned mitigation techniques.