STIS Cycle-29 Calibration Phase-1 Template Last Revised: 05/04/2021 Proposal ID: xxxxx Title: CCD Spectroscopic Dispersion Solutions PI: D. Welty Co-I(s): --------------------------------------------------------------------------- # Orbit estimates are TOTAL for all of cycle-29; assume 53 weeks) Total Prime Orbits: 0 External Parallel Orbits: 0 Internals or no-impact orbits: 3 Comments on orbit estimate: annual monitoring program --------------------------------------------------------------------------- # This section should be written with a GO audience in mind -- use # Calibration plans in WFPC-2 handbook as a guide. Purpose: to monitor the accuracy of the CCD wavelength calibration / dispersion solutions Description: Internal wavecals will be obtained with all 6 gratings (G230LB, G230MB, G430L, G430M, G750L, G750M) supported for use with the CCD, at the representative wavelength settings that have been monitored since cycle 18. All observations will be obtained with the 52x0.1 aperture, which maps to 2 pixels at the CCD. The HITM1 lamp will be used (rather than the LINE lamp), as it has a more favorable spatial illumination pattern, dropping by only a factor of 3 at row 900 (near the E1 pseudo aperture used for faint targets), relative to the peak brightness at row 420. The slight adjustments made in cycle 26 to account for the fading of the calibration lamps are maintained: all exposure times are the same as those used for cycle 26 and all exposures are at a lamp current of 10 mA. Accuracy: 0.2 pixels Comments on Accuracy: While wavelength dispersion relation coefficients are tabulated every 32 rows in the CCD dispersion (_dsp) reference file, the wavelength accuracy goal is for row 900. Exposure times in this program have typically been chosen to yield a S/N ratio of at least 10 per pixel in row 900 after combining 32 rows. This constraint must be satisfied in the left, middle, and right thirds of the image. Existing HITM1 wavecals from the past several cycles (which indicate the current rate of fading of the lamp) were used to set the exposure times. Products: The accuracy of the existing CCD dispersion (_dsp) reference file will be assessed and described in a Cycle 29 close-out report. If necessary, a new reference file will be created and delivered along with a supporting Instrument Science Report (ISR). --------------------------------------------------------------------------- # Link to Cycle 29 Science # Use the GO + GTO Phase 1 exposure listing and derived statistics # posted on WWW. Fraction of science programs supported by this calibration: 16.5% of STIS total exposure time (cycle 28). List categories of science which can't be executed until after this proposal: none why: List categories of science which are best performed contemporaneously with this proposal: none why: calibrations can be applied after the observations --------------------------------------------------------------------------- # THE REST OF THIS FORM IS FOR INTERNAL USE --------------------------------------------------------------------------- Observation summary: Internal wavecals (TARGET=NONE, LAMP=HITM1) will be obtained with all 6 gratings (G230LB, G230MB, G430L, G430M, G750L, G750M) supported for use with the CCD. All observations will be obtained with the 52x0.1 aperture (which maps to 2 pixels at the CCD), at a lamp current of 10 mA. Below is a summary table with information about each exposure in this program: grating (column 1), central wavelength (column 2), exposure time (column 3), and gain (column 4). Grat Wave Exptime GAIN Comment (A) (s) G230LB 2375 2x120. 4 G230MB 1995 3x218. 1 G230MB 2416 2x55. 1 G230MB 2697 25. 1 G230MB 3115 34. 1 G430L 4300 11. 4 G430M 3165 11. 1 G430M 3680 11. 1 G430M 4961 30. 1 G430M 5471 30. 1 G750L 7751 6.2 4 G750M 5734 5.9 4 G750M 6768 3.9 4 G750M 8311 10. 4 G750M 9336 10. 1 Special Requirements or options.........: GAIN=1 or 4 (see table above) Comments: once per year # Exposure list plan at the Phase I level. Be as complete as reasonable. # If possible information should be complete enough to allow easy # submission of a Phase 2 from this form. However, if you have to leave # some of the fields blank below, or want to provide the information # in another format, that is acceptable. (Make sure you do the BOP checking # though, as this is a phase-1 issue.) Table of exposures (copy for each exposure as appropriate/desired): Target or lamp..........................: HITM1 Type of Acquisition.....................: none - internal Detector for observation................: CCD Operating mode .........................: ACCUM Spectral Element........................: G230LB Aperture................................: 52x0.1 Central Wavelength......................: 2375 Exposure Time...........................: 120 S Number of Iterations ...................: 2 BOP Predicted Local Count Rate for MAMA.: n/a BOP Predicted Global Count Rate for MAMA: n/a ETC PID IDs for Count Rates.............: n/a Special Requirements or options.........: GAIN=4 Comments: Target or lamp..........................: HITM1 Type of Acquisition.....................: none - internal Detector for observation................: CCD Operating mode .........................: ACCUM Spectral Element........................: G230MB Aperture................................: 52x0.1 Central Wavelength......................: various (see table above) Exposure Time...........................: various (see table above) Number of Iterations ...................: 1-3 (see table above) BOP Predicted Local Count Rate for MAMA.: n/a BOP Predicted Global Count Rate for MAMA: n/a ETC PID IDs for Count Rates.............: n/a Special Requirements or options.........: GAIN=1 Comments: Target or lamp..........................: HITM1 Type of Acquisition.....................: none - internal Detector for observation................: CCD Operating mode .........................: ACCUM Spectral Element........................: G430L Aperture................................: 52x0.1 Central Wavelength......................: 4300 Exposure Time...........................: 11 S Number of Iterations ...................: 1 BOP Predicted Local Count Rate for MAMA.: n/a BOP Predicted Global Count Rate for MAMA: n/a ETC PID IDs for Count Rates.............: n/a Special Requirements or options.........: GAIN=4 Comments: Target or lamp..........................: HITM1 Type of Acquisition.....................: none - internal Detector for observation................: CCD Operating mode .........................: ACCUM Spectral Element........................: G430M Aperture................................: 52x0.1 Central Wavelength......................: various (see table above) Exposure Time...........................: various (see table above) Number of Iterations ...................: 1 BOP Predicted Local Count Rate for MAMA.: n/a BOP Predicted Global Count Rate for MAMA: n/a ETC PID IDs for Count Rates.............: n/a Special Requirements or options.........: GAIN=1 Comments: Target or lamp..........................: HITM1 Type of Acquisition.....................: none - internal Detector for observation................: CCD Operating mode .........................: ACCUM Spectral Element........................: G750L Aperture................................: 52x0.1 Central Wavelength......................: 7751 Exposure Time...........................: 6.2 S Number of Iterations ...................: 1 BOP Predicted Local Count Rate for MAMA.: n/a BOP Predicted Global Count Rate for MAMA: n/a ETC PID IDs for Count Rates.............: n/a Special Requirements or options.........: GAIN=4 Comments: Target or lamp..........................: HITM1 Type of Acquisition.....................: none - internal Detector for observation................: CCD Operating mode .........................: ACCUM Spectral Element........................: G750M Aperture................................: 52x0.1 Central Wavelength......................: various (see table above) Exposure Time...........................: various (see table above) Number of Iterations ...................: 1 BOP Predicted Local Count Rate for MAMA.: n/a BOP Predicted Global Count Rate for MAMA: n/a ETC PID IDs for Count Rates.............: n/a Special Requirements or options.........: GAIN=1 or GAIN=4 (see table above) Comments: --------------------------------------------------------------------------- # Special needs of this proposal? Scheduling: 2021 Nov-Dec Prerequisites: none PDB update? N On-board table update? N # Special Requirements: Real time? N Special commanding? N Quick Data turnaround? N Special timing required? N Other? N Describe (& justify) special requirements: ------------------------------------------------------------------------- # Analysis Plan Expected FTE weeks for analysis: 2 weeks Required turnaround on analysis (weeks): not critical Data volume needed for analysis (Mb): 400 Mb Special software needed for analysis? (Describe): Custom (or modified) IDL software may be needed to create new dispersion (_dsp) reference files. Description of analysis Plans: Raw wavecal images will be self-calibrated using Calstis software. Existing wavelength solutions will be tested with available software within IRAF and IDL.