Spitzer Documentation & Tools

Purpose: IDL procedure to fix the "first-frame" effect for IRAC observations using repeats. Especially for channel 3 BCDs, the first frame correction is not very good for the second and subsequent repeats at a given pointing. If repeats were used in the creating the AOR, the channel 3 images will have a slight residual bias which has a distinct pattern across the image.

Author: Sean Carey
Date Contributed: 1 Sep 2005
System Requirements: IDL v5.3 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 repeat_delta_dark.pro (PRO, 6 KB)

This procedure constructs a "delta-dark" from the difference images of the repeat with the corresponding first BCD in each pointing. The derived delta-dark is then applied to each repeated frame. The algorithm is described in detail in the header comments in the procedure source code.

The software has been tested on Solaris 9 and Mac OS 10.3.9 with IDL versions 5.6 and 6.1.