Calibration programs will monitor COS performance and will provide information needed to calibrate supported observing modes. Each cycle, a set of calibration programs will be assembled and approved by the Director. The following is a table of all the calibration plans.
The summary tables contain the list of all the calibration programs for each cycle. The final calibration plans describe briefly the purpose, accuracies, and resources for each of these programs. The results and status of the calibration programs at the end of each cycle will be documented in the closeout reports.
Calibration Program Summaries
COS Airglow Observations
The COS team has provided high-S/N observations of the geocoronal Lyman-alpha line profile observed with the G130M and G140L gratings in previous calibration cycles. These observations allow users to model and subtract the line wings from their spectra.
These programs were discontinued after Cycle 24 in accordance with the COS 2025 policy, which aims to protect and extend the lifetime of COS in part my severly limiting the instrument's exposure to Lyman-alpha airglow.
We provide a listing of both deliberate and accidental airglow observations on the COS Airglow Web Page. You can also find community generated observational templates for four geocoronal emission lines at the bottom of the page. If you discover any others, please let us know! In addition, we have posted a list of airglow lines observed in FUSE and HUT data which may be present in COS observations.