17.10 Cycle 13 Calibration

The Cycle 13 calibration plan largely continues the routine monitoring programs of Cycle 12. These programs were trimmed in Cycle 12 where the stability of instrument performance and the completeness of prior calibration permitted. Much of the calibration plan is devoted to producing timely darks, biases, flats, sensitivity corrections, and corrections for the steady degradation of charge transfer efficiency (CTE). Testing is under way to apply time-dependent sensitivity corrections to images and to echelle spectra; corrections are already being applied to first-order spectra. Extracted CCD spectra are now being corrected for CTE losses as well as sensitivity changes (see STIS ISR 2003-03), based on a combination of programs to characterize the CTE losses at different signal and background levels and on iterative analysis of sensitivity changes and CTE losses.

New or additional observations are planned in the following areas:

Additional observations are needed to characterize throughput for a few configurations using detector-centered and E1 apertures. More exposures will also be taken to support the production of flats for E1 apertures.

The HITM1 calibration lamp is used to produce wavecals for many configurations, and to illuminate the reference aperture during the STIS target acquisition procedure. After a few instances of late or failed lamp turn-ons in these observing modes, a program was added in Cycle 12 to characterize the performance of the alternate HITM2 calibration lamp. More HITM2 observations will be made in Cycle 13, including MAMA observations as well as additional CCD observations.

A new geometric distortion solution was recently produced for the NUV-MAMA (STIS ISR 2004-01). Observations will be made in Cycle 13 to support the production of new geometric distortion solutions for the FUV-MAMA and the CCD.

4. The effects on spectral images of mis-centering a target in the slit will be investigated. This program will supplement GO observations for a limited set of configurations and calibration program observations of a source placed beyond the edge of the slit.

In Cycle 12, members of the HST European Coordinating Facility (ECF) collaborated with STScI staff to take deep wavecals in the echelle modes to support their production of improved dispersion solutions. In Cycle 13, a GO program will take echelle wavecals at a variety of time intervals to test the stability of the wavelenth scales over periods of days to months. As a supplement to this program, ECF and STScI staff will conduct an echelle wavecal program that samples the sub-orbital time-scale to characterize the effects of bright/shadow transition, thermal cycling, and potential geomagnetic influence.


	If your program requires unique calibrations beyond those that are planned (use the Cycle 7-13 Calibration Programs as a guide) and that are of direct benefit to other STIS users, then you should apply directly for this calibration in your Phase I proposal.

Space Telescope Imaging Spectrograph Instrument Handbook for Cycle 14

17.10 Cycle 13 Calibration