Spitzer Documentation & Tools

Purpose: Corrects vertical pinstriping (also known as "jailbars") in IRAC images.

Author: Jason Surace (SSC/IPAC)
Date Contributed: 11 Apr 2006
System Requirements: IDL v5.2 or higher; astrolib IDL library

This software is not considered part of the pipeline and no installation support from IRSA should be expected. We are however very interested in your feedback in order to improve or replace the algorithm and are glad to work with you in test cases and analysis. Questions and comments should be directed to the Helpdesk.

Information and Download

Download jailbar.pro (PRO, 2 KB)

Each IRAC detector has four readout channels, each of which reads a vertical alternating column in the array. As a result, every 4th column in the array may have a slightly different bias level. Under some circumstances these levels may be significantly different, leading to an appearance of vertical stripes in the image. A BCD pipeline module called DARKDRIFT corrects for this. For S13 processing only, this module was turned off for channels 1, 2, and 4.

This IDL routine applies a similar correction to an IRAC image. It computes the median levels of each readout channel, and then applies an additive correction to make them equal to their arithmetic mean.