This activity monitors NIRCam's distortion and global alignment by visiting the LMC Calibration Field in both imaging and coronagraph imaging. The data will be used to determine the plate scale, orientation, and geometric distortion for each SCA in each NIRCam module over the full wavelength range. These observations use a combination of dithers and mosaics to overlap all SCAs onto the same location within the LMC. 

We use F210M and F335M with FGS in parallel for the overall FGS SIAF alignment.

We observe all NIRCam filters with either MIRI or NIRCam in parallel, which will provide intra-instrument relative alignment.

We use a 2x2 mosaic with a large overlap and no dithers in order to observe the different filters with a minimal change of guiding for each position. 

For coronagraphy we chose one of the brightest star of our previous LMC field (K mag ~10, always saturated) and the aim of Obs 5 is to observe it using the coronagraphic template to check precisely its landing position behind the MASK335R occulter (using all other stars) against the techniques used with a single star (cross correlation with small grid dithers and a grid of PSF models). Obs 6 is using NB filters and CLEAR pupil to acquire that star unsaturated and make sure its position is well know with respect to the other stars. For that we used the 640 subarray.

This is a continuation to Cycle 2 CAL program 4451 (CAL-NIRCAM-215) which aimed at determining the best strategies to use for most high contrast science cases where NIRCam coronagraphy is considered:

• When (not) to use the bar, when to use the small round mask, etc.
• To inform better the community.

The measurements also feed a public and documented PSF library and will be complementary to the GTO 1412: "Characterizing 51 Eridani Exoplanetary System" (executed with the LWB NARROW setup only but with other, more pertinent for science, filters). 

The 51 Eri b exoplanet is ideal for this calibration program because it very challenging both in flux and angular separation.

It would be difficult for the community to request it again and very informative and scientifically useful to observe it with different masks in addition to potentially increasing the photometric characterization (better SNR in the redundant filters, when detected). This program should be carried out once all target acquisitions are optimized (TA centroiding algorithm, small angle maneuver repeatability). Having the dual SW/LW will allow in some case to also learn further about the data collected on the non-optimized channel.

Of course, this program also allows to refine and calibrate our simulation tools (pyNRC and PanCAKE) which are used to populate a full parameter space. The ultimate goal is to build an interactive "JIST like" tool for NIRCam Coronagraphs (which can then be expanded to MIRI Coronagraphs.

Program 4451, was executed in September 2023 (obs 1-8, see table 1 below) and February 2024 (obs 9-12). 

As expected, it is extremely challenging to detect the 51 Eri b companion as shown on Figure 1. In fact, so far, in the GTO Program 1412 acquired with the LWB NARROW setup, b is marginally detected only through the F460M filter, one of the most sensitive for young giant exoplanets, a filter our program does not use. Our analysis of the data so far shows an evolution of the bad pixels as well as, still a small but sub-optimal target acquisition centering. In fact, Program 4451 obs 7-8 where used to optimize the TA special requirement offsets for Program 1412 to be successful. Below are the values (dX / dY) by which we “missed” each occulter as determined with Jarron Leisering’s methods (multi-fit with simulations grid representing all small grid dithers). In orange (also in Table 1) the bar observation we suggest to repeat in the CAL-NIRCAM-315.

This program characterizes the NIRCam persistence (latent images) and checks for changes since the Cycle 1 calibration persistence analysis. This is a continuation from Cycle 1 calibration, which is to revisit and observe a rich stellar field, Omega Cen (NGC-5139), with a long enough exposure time to probe a wide range of over-saturation levels. This is followed by a series of darks and a final short dithered sequence in a narrow-band filter to recover the source photometry. 

The illumination exposure is preceded by a series of dark integrations, providing a baseline measure of the dark and noise floor to verify that no persistence from previous observations has been imprinted on the detector. The length of this preliminary dark can be shortened if scheduling can guarantee that the detector has not been exposed in the previous ~10,000 seconds. The dark has to be taken 'on site,' i.e., after the target has been acquired. This is necessary to prevent spurious exposure to bright sources during the telescope slew and target acquisition maneuver.

We request bi-monthly observations of the LMC astrometric field for monitoring of the NIRISS photometric stability and as a quick check on the astrometric stability of the instrument. This is a continuation of Cycle 1 calibration program 1515 and Cycle 2 program 4475.

This program will obtain full frame NIRSpec dark exposures in NRSRAPID and NRSIRS2RAPID readout modes in order to create updated dark and bias reference files. Six epochs (with overlap) are implemented via "between" special requirements, so that darks can be acquired throughout Cycle 3. This is in order to have enough contemporary dark data to create new reference files every 4-6 months, as the hot pixel population is changing over time. Observations can be executed in parallel with no constraints on pointing.

Ideally, IRS2 darks should be scheduled when the detector system is expected to be in IRS2 readout mode, and traditional (TRAD) darks should be scheduled when the detector system is expected to be in traditional readout mode, based on nominal execution of the observation plan. This is to minimize detector/ASIC temperature drifts after switching readout mode that can negatively impact dark data. 

Obtain NIRSpec darks of sufficient integration length in NRSRAPID readout mode for all used subarrays in order to create/update the SUPERBIAS, DARK, and READNOISE reference files (subarray) for NIRSpec.

Estimate the flux contribution of the background in TSO (Time-Series Observations) taken at the celestial pole and celestial equator. NIRISS/SOSS TSO observations of transiting exoplanets obtained during commissioning and Cycle 1 have demonstrated that the background contribution to these observations is significant. 

The aim of this program is to take measurements of the zodiacal light background in the CLEAR/PRISM and F290LP/G395H configurations at two pointings, one near the ecliptic and one near the north ecliptic pole, to determine the level of variability of the background for the S1600A1 aperture for these modes.

This program executes successive rotations of the GWA (grating wheel assembly), one position at a time, with an internal lamp exposure taken at each position (LINE4 for the PRISM, REF for the gratings). The data will enable monitoring of the calibration of the GWA tilt sensors, which is a critical part of the NIRSpec wavelength calibration. This calibration is part of the NIRSpec instrument model, but the tilt sensors are more likely to change with time than the other internal instrument model components and will be monitored more frequently. The monitor will run approximately once every 4 weeks to provide data on the GWA tilt behavior and build up statistics for a full tilt calibration if necessary.  

See APT file proposal description section for more detailed information. This Cycle 3 program is essentially identical to the structure of the Cycle 2 program 4463, which had implemented a new and more efficient scheduling structure that was developed part way through the execution of the Cycle 1 program (1491).

This proposal will redo the observations needed to define the NIRSpec MOS F-Flats, using white dwarf standards for cleaner spectra. We will use a different star for the G140M settings as we need one faint enough that we can get at least 3 unsaturated groups at all wavelengths.

These new observations are needed because of centering problems with the commissioning observations, (OBS 19 of PID 1128), and because the star used for commissioning has been shown to be variable at the ~1% level. It was also a bit too bright for the G140M settings.

This program provides additional data for the MOS S-flat (spectroscopic flat field) reference files. The MOS S-flat is a cube with complete but sparse sampling in wavelength space per pixel. This allows the calibration of MOS spectra, regardless of the location of the MSA shutters used. Data will be obtained through 20 MSA long slit configurations using the CAA internal calibration FLAT lamps to expand the wavelength interpolation of the S-flat. The S-flat is one part of the 3 component NIRSpec flat field: the F-flat traces the field-dependent throughput of the OTE and instrument FORE optics, the S-flat traces the light path from the micro-shutter array up to but not including the FPA and the D-flat consists of the pixel-to-pixel variations of the detector.

This will monitor the flat field of the FGS channels. There is significant structure in the lamp flats, however, these lamp flat fields are good for monitoring trends in the response of the detector over time. The internal calibration lamp shall be used, so Fine Guiding will not be possible, hence ACS will be under coarse control. Exposures will use full frame images. Each exposure is repeated five times for cosmic ray rejection. After the full frame data are obtained, a 1 arcminute telescope offset is to be executed and the imaging sequence is to be repeated to allow for sky-source removal (the FGS has no shutter or opaque element). There will be only one epoch of observations for Cycle 3; this is nominally scheduled for the Sep-Dec 2024 timeframe.

This program obtains observations of A dwarf stars as part of the JWST absolute flux calibration effort. This effort uses all JWST instruments to provide absolute flux calibration for all JWST modes (filters, gratings, etc). The combined nature of this effort is to ensure the highest quality flux calibration internal to and between instruments and to carry out the observations efficiently. This program provides observations of A dwarf stars and companion programs provide observations of hot stars and solar analog observations.  The absolute flux observations will be compared to model predictions of the stars' flux densities to calculate the appropriate calibration factors per instrument mode.

This program obtains repeated observations of two stars as part of the JWST absolute flux calibration effort.  This effort uses all JWST instruments to provide absolute flux calibration for all JWST modes (filters, gratings, etc). The combined nature of this effort is to ensure the highest quality flux calibration internal to and between instruments and to carry out the observations efficiently. This program provides observations of two stars spread throughout the year to measure the repeatability of JWST observations. The aim is to observe in one filter/grating/etc per detector to measure how repeatable an observation is in instrument units. The expectation is that the repeatability is set at the detector level.

This program monitors the full-frame and subarray noise properties by taking dark observations throughout Cycle 2 using the equivalent of every readout pattern. The Darks are set up to characterize the dark current, 1/f noise, IPC, cross-talk, and superbias. We note that the dark current itself is so low (1.9/27 e-/ks for the shortwave/longwave channel) that achieving a good S/N per pixel is prohibitive for the shortwave channel. However, hot pixels are still characterized, and the overall temporal evolution of the dark current can be monitored with the median of the full frame. Dark frames are particularly important for subarrays because of ‘glow’ from the amplifiers, which accumulates each time a pixel is read out. Since subarrays have short frametimes, the glow accumulates much faster than it does in the full frame images. The glow may produce significant structure across subarrays, and is also expected to change if the ASICs are re-tuned. For this activity, the pupil wheels will be set to the “Dark” position. We will obtain 5 epochs of darks, with a similar cadence for the full-frame and subarray darks.

Instead of taking dedicated sky flats during Cycle 2, we will use the deep field GTO data to reconstruct P-flats in a subset of filters. Since we cannot control when the GTO data are obtained, we will also monitor the stability of the sky flats with the F070W and F277W filter pair. We will obtain 6 epochs, which are scheduled in parallel with NIRISS sky flats. Large scale frequency variations in the NIRCam illumination pattern (L-flats) will be measured in CAL-NIRCAM-203, in combination with the data from this program and GTO data.

This activity monitors NIRCam's distortion and global alignment by visiting the LMC Calibration Field in both imaging and coronagraph imaging. The data will be used to determine the plate scale, orientation, and geometric distortion for each SCA in each NIRCam module over the full wavelength range. These observations use a combination of dithers and mosaics to overlap all SCAs onto the same location within the LMC. For all observations, we use a subset of the available filters and observe with FGS in parallel.

The purpose of this activity is to measure count-rate linearity in the FULL frame, and in all science and calibration subarrays. The program requires observations of a rich stellar field that is bright and dense down to the confusion limit. The goal is to probe the linearity of a large sample of pixels across the detector/subarray by exposing in RAPID mode up to saturation. This program will target the LMC calibration field, which is in the CVZ. Observations between the FULL frame and the subarrays are set at the same field point to ensure the same stars are detected at the same spots on the detector.

This program will monitor the calibration of NIRCam's long wavelength (LW) grism, including wavelength calibration and the line-spread function (LSF) characterization. The wavelength solution will be determined by observing a planetary nebula (PN) in the LMC, which has a weak continuum and a rich set of strong spectral lines. The PN is also sufficiently compact to enable the LSF to be measured. The same target was observed both in Commissioning and Cycle 1. We include both grisms in Cycle 2 (GRISMC and GRISMR), on both modules, over the full NIRCam wavelength range.

This program will collect spectra of the sky background in a sparsely populated star field in the ecliptic plane using both NIRCam grisms. By comparing background subtracted versus non-subtracted archival NIRCam transit spectroscopy, we will inform the exoplanet community for the limitations introduced by the sky background at NIRCam wavelengths. The data and results from this program will establish a background calibration reference file and improve the NIRCam observing strategy of future exoplanet observations.

This program aims at determining the best strategies to use for most high contrast science cases where NIRCam coronagraphy is considered:

• When (not) to use the bar, when to use the small round mask, etc.
• To inform better the community.

The measurements will also feed a public and documented PSF library and will be complementary to the GTO 1412: "Characterizing 51 Eridani Exoplanetary System".

The 51 Eri b exoplanet is ideal for this calibration program because it very challenging both in flux and angular separation. It would be difficult for the community to request it again and very informative and scientifically useful to observe it with different masks in addition to potentially increasing the photometric characterization (better SNR in the redundant filters, when detected). This program should be carried out once all target acquisitions are optimized (TA centroiding algorithm, small angle manoeuver repeatability). Having the dual SW/LW will allow in some case to also learn further about the data collected on the non-optimized channel.

Of course, this program will allow to refine and calibrate our simulation tools (pyNRC and PanCAKE) which will be use to populate a full parameter space. The ultimate goal is to build an interactive "JIST like" tool for NIRCam Coronagraphs (which can then be expanded to MIRI Coronagraphs).

An absolute flux standard star will be placed on each subarray to measure any count-rate differences between subarray and full frame read-out modes. In each case, a full frame image is taken at the same field point used for the subarray. Every aperture (subarray and full) used for science or calibration is included.

This program will allow an initial characterization of the throughput, wavelength solution and background structure for the NIRCam Dispersed Hartmann sensor on the SW channel. The aim is to inform future decisions for the detailed implementation of Time-Series spectroscopy using the DHS0 and the LW GRISMR simultaneously. This science enhancement is currently under development with a goal to be offered in future JWST cycles.

Perform an end-to-end test of NIRCam Dual Channel (LW+SW) Coronagraphy (available in late Cycle 1) for each occulting mask to demonstrate basic functionality of the mode, correct commanding of new subarrays, and proper data flow and processing through DMS.

We request time to make deep imaging PSF observations of a bright, isolated star to measure the faint PSF wings. The purpose of the observations is to provide template PSFs for bright, saturated stars to allow profile fitting photometry using only the PSF wings. Such measurements have been valuable for the Spitzer Space Telescope, and in the NIRISS case are needed because most of the stars seen in imaging mode that are in existing photometric catalogues (2MASS or WISE, for example) are saturated even in short NIRISS exposures.

A re-measurement of the NIRISS distortion and offset from the Guider is requested for trending of any possible changes in the astrometric distortion with time. A single epoch observation will be made in all the NIRISS imaging filters using the same pointing in the Large Magelanic Cloud astrometric field as was used for this purpose in commissioning and in Cycle 1 calibration.

This program provides internal lamp flat observations to be carried out during slews. These observations allow a direct comparison with groundbased data taken in the CV3 and OTIS testing to see whether the detector properties have changed. This continues program 1503 from Cycle 1.

Parallel dark current observations are needed for NIRISS in the NISRAPID read-out mode. These are used to produce the dark current reference file and also for general health analysis for the instrument. Analysis of the pixel properties will be used to update the NIRISS bad pixel mask as needed.

Dark exposures are taken in the different science sub-arrays to produce the pipeline reference files for these read-out patterns. There are 4 sets of observations with 3 months between sets.

We request bi-monthly observations of the LMC astrometric field for monitoring of the NIRISS photometric stability and as a quick check on the astrometric stability of the instrument. This is a continuation of Cycle 1 calibration program 1515.

An isolated, bright star will be observed in the NIRISS SOSS mode, but with full frame read-out and with the spectrum offset from the top of the array down to the center so that measurements of the total signal including the far wings of the profile can be made. By comparing the total signal to the signal within the normal spectral extraction aperture, the aperture corrections will be estimated for orders 1 and 2 in the SOSS mode.

We request observations of an isolated reasonably bright star in the NIRISS WFSS mode in order to characterize the higher spectral orders (-1, 3, and 4) that can cause contamination of science spectra. The properties of these higher orders need to specified so that the contamination corrections in the JWST data reduction pipeline can be done accurately. The calibration consists of taking a nomal WFSS observation of the isolated star in different grisms and blocking filters.

Observations of two stars, selected to be single stars, will be made in the AMI mode with the three medium-band filters to test that the star can be positioned consistently at the centre of a pixel allowing for the filter-to-filter offsets that are observed in normal imaging. Having a consistent position for the observations in different filters is helpful in the analysis of the amplitudes and phases of the interference pattern observed through the mask, and should improve the AMI sensitivity.

Observations of the zodiacal light background are requested for 6 pointings, one of which is repeated to give some indication of whether there is a variability to the background from acquisition to acquisition depending on the grism position. Each field is fairly empty by the standards of the SOSS mode with no star bright enough to acquire. Observations are taken without an acquistion in full frame read-out with the GR700XD grism in the beam. No observations in the F277W filter are requested here. Analysis of these observations will allow some evaluation of how much the background may vary from pointing to pointing, and we expect to produce a number of zodiacal background template shapes from these data that can be used in the analysis of SOSS time series.

Observations of four single stars as AMI mode calibration sources are requested. The first two have closely matched brightesses and the third star is of similar spectral type but is a factor of 1.5 fainter. The last star is the same brightness as the third star but of a somewhat different spectral type. Cross-calibrations of these stars with each other will give information to guide the requirements needed for selecting AMI phase calibration sources.

A series of AMI mode observations with sub-pixel offsets are requested of the AB Dor binary system and a single star phase calibration target. This star was previously observed in commissioning. Analysis of these observations compared to the commissioning observations will provide information about the effect of small mis-matches in the calibration source and the science target on the the contrast that can be achieved in the data reduction.

This program will obtain full frame NIRSpec dark exposure in NRSRAPID and NRSIRS2RAPID readout modes in order to create updated dark and bias reference files. Five epochs (with overlap) are implemented vie between special requirements, so that darks can be acquired throughout Cycle 2. This is in order to have enough contemporary dark data to create new reference files every 4-6 months, as the hot pixel population is changing over time. Observations can be executed in parallel with no constraints on pointing. Ideally, IRS2 darks should be scheduled when the detector system is expected to be in IRS2 readout mode, and traditional (TRAD) darks should be scheduled when the DS is expected to be in traditional readout mode, based on nominal execution of the observation plan. This is to minimize detector/ASIC temperature drifts after switching readout mode that can negatively impact dark data.

Obtain NIRSpec darks of sufficient integration length in NRSRAPID readout mode for all used subarrays in order to create/update the SUPERBIAS, DARK, and READNOISE reference files (subarray) for NIRSpec.

This program provides additonal data for the MOS S-flat (spectroscopic flat field) reference files. The MOS S-flat is a cube with complete but sparse sampling in wavelength space per pixel. This allows the calibration of MOS spectra, regardless of the location of the MSA shutters used. Data will be obtained through 20 MSA long slit configurations using the CAA internal calibration FLAT lamps to expand the wavelength interpolation of the Sflat. The S-flat is one part of the 3 component NIRSpec flat field: the F-flat traces the field-dependent throughput of the OTE and instrument FORE optics, the S-flat traces the light path from the micro-shutter array up to but not including the FPA and the D-flat consists of the pixel-to-pixel variations of the detector.

This program will acquire the spectroscopic (lamp) flats for the FS mode using the ALLSLITS subarray. Observations will be acquired for all of the NIRSpec disperser/lamp combinations. These observations are essential for minimizing flat field calibration noise for FS and/or BOTS observations that need improved signal-to-noise. In addition to the commissioning and Cycle 1 flats, these flats will further decrease the noise from flat fielding process for science observation processing. The S-flat is one part of the 3 component NIRSpec flat field in addition to the Fflat and the Dflat.

This program will obtain observations of a spectrophotometric standard star in order to further characterize wavelength dependent throughput variations as a function of position in the slit for FS and IFU modes. Data will be taken for the fixed slit 2-point and 5-point dither patterns and the 21st through 40th points in the IFU cycling pattern and will build on the data already obtained in commissioning (the fixed slit 3-point dither pattern and the first 20 points of the IFU cycling pattern).

Internal lamp observations (executed during slews to minimize impact) are used to monitor the status of NIRSpec MSA shutter operability and hence allow update of MSA operability masks (failed open and failed closed shutters) used in observation planning and pipeline reduction. Undispersed MSA images, illuminated by the internal lamp, are taken through a set of four diagnostic shutter patterns. An ALLCLOSED pattern is used to find all shutters that are “Failed Open” (fail to close when commanded). An ALLOPEN pattern and a pair of checkboards (CHKBD1x1-1, CHKBD1x1-2) are used to recover the best-case and worst-case population of “Failed Closed” shutters (those that fail to open when commanded). Each exposure uses NRSIRS2RAPID readout, with 7 groups x 1 integration. The set of four exposures are acquired every month to monitor trends in operability and keep the map used for planning up-to-date. The observations are executed as slew parallels to maximize efficiency. An additional long exposure (65 groups x 1 integration, 949 s, 1506 s with overhead) through the ALLCLOSED configuration is obtained once per year, to yield a high dynamic-range contrast map.

From a set of internal CAA lamp exposures, this activity, along with the GWA tilt calibration monitor program, will serve to monitor the NIRSpec instrument model during Cycle 2. The instrument model is a parametric model of NIRSpec optical geometry and is used to trace, extract and rectify the spectra and provides WCS information for each pixel in a 2D spectrum. Most model components are expected to remain stable, but a limited monitor will guard against changes not traceable via existing observations.

This calibration program may change in response to the analysis of the Cycle 1 monitoring program (PID 1489).

This program executes successive rotations of the GWA (grating wheel assembly), one position at a time, with an internal lamp exposure taken at each position (LINE4 for the PRISM, REF for the gratings). The data will enable monitoring of the calibration of the GWA tilt sensors, which is a critical part of the NIRSpec wavelength calibration. This calibration is part of the NIRSpec instrument model, but the tilt sensors are more likely to change with time than the other internal instrument model components and will be monitored more frequently. The monitor will run approximately once every 4 weeks to provide data on the GWA tilt behavior and build up statistics for a full tilt calibration if necessary. See APT file proposal description section for more detailed information.

Estimate the flux contribution of the background in TSO (Time-Series Observations) taken at the celestial pole and celestial equator. NIRISS/SOSS TSO observations of transiting exoplanets obtained during commissioning have demonstrated that the background contribution to these observations is significant. The aim of this program is to take measurements of the zodiacal light background in the CLEAR/PRISM and L290LP/G395H configurations at two pointings, one near the ecliptic and one near the north ecliptic pole, to determine the level of variability of the background for the S1600A1 aperture for these modes.

Sample the slit losses for the MSA shutters in the 1x1 and 1x3 shutter case at any given position of the shutter. The observations conducted during commissioning didn’t sufficiently sample the corners of the MSA shutter, thus an accurate and smooth slit loss calibration could not be produced. We will add extra slit losses measurement for MOS at the corners of one shutter.

This activity is needed to verify and trend the behavior of the two NIRSpec wheel mechanisms (FWA and GWA). Pending any unexpected behavior, the GWA characterization will be done twice during Cycle 2 (in August and in October) in order to maintain the agreed bi-weekly cadence. The FWA characterization will only be done once (in October). The procedure collects NIRSpec-focused telemetry data in the HC buffer at each commanded wheel position, and sends them to the ground for inspection after the procedure is completed. A series of mechanism move commands will be issued to step the FWA/GWA one position at a time through all 8 wheel positions, in both the forward and reverse directions. At each position, the HC buffer is armed before a move and then dumped after the move. The procedure acquires internal calibrations with NIRSpec as the prime instrument, and takes approximately 1 hour to execute for each mechanism.

Contingency program for MSA ESD. When a new MSA short appears, if it is detectable in telemetry, ESD should be executed on the relevant MSA Quad in order to locate the short and mask the shutter row/column as necessary. After ESD, diagnostic exposures can also be executed to verify that all associated glow has also been removed.

Contingency program for MSA OSD. When a new MSA short appears, if it is *not* detectable in telemetry, OSD diagnostic exposures should be executed in combination with test short masks in order to locate the short and mask the shutter row/column as necessary.

Program for re-checking previously masked shorts, as the expectation is that some (many?) could have been transient, and the shutters could be resurrected for science operations.

This will monitor the flat field of the FGS channels. There is significant structure in the lamp flats, however, these lamp flat fields are good for monitoring trends in the response of the detector over time. The internal calibration lamp shall be used, so Fine Guiding will not be possible, hence ACS will be under coarse control. Exposures will use full frame images. Each exposure is repeated five times for cosmic ray rejection. After the full frame data are obtained, a 1 arcminute telescope offset is to be executed and the imaging sequence is to be repeated to allow for sky-source removal (the FGS has no shutter or opaque element). Epoch 1 observations should be done Oct-Dec 2023 timeframe. Epoch 2 observations should be done within the Mar-Apr 2024 timeframe.

This proposal monitors the geometric distortion & pixel scale of both FGS Guide channels. The LMC astrometric field is imaged via FGS in calibration mode, obtaining full frame images at 5 different positions within the astrometric field for each of the two channels. The mid-point of the catalog will be placed at the center of the FGS channel being calibrated (the other channel will be guiding). This will ensure that (1) the same stars are used to calibrate FGS1 and FGS2, and (2) we will thus obtain an accurate measure of the relative sensitivity of Guiders 1 & 2. This program is similar to CAR-FGS-011. Epoch 1 observations should be done Sep-Oct 2023. Epoch 2 observations should be done Apr-May 2024.

This program obtains observations of A dwarf stars as part of the JWST absolute flux calibration effort. This effort uses all JWST instruments to provide absolute flux calibration for all JWST modes (filters, gratings, etc). The combined nature of this effort is to ensure the highest quality flux calibration internal to and between instruments and to carry out the observations efficiently. This program provides observations of A dwarf stars and companion programs provide observations of hot stars and solar analog observations. The absolute flux observations will be compared to model predictions of the stars' flux densities to calculate the appropriate calibration factors per instrument mode.

This program obtains observations of hot stars as part of the JWST absolute flux calibration effort. This effort uses all JWST instruments to provide absolute flux calibration for all JWST modes (filters, gratings, etc). The combined nature of this effort is to ensure the highest quality flux calibration internal to and between instruments and to carry out the observations efficiently. This program provides observations of hot stars and companion programs provide observations of A dwarfs and solar analog observations. The absolute flux calibrations will be compared to model predictions of the stars' flux densities to calculate the appropriate calibration factors per instrument mode.

This program obtains observations of solar analogs as part of the JWST absolute flux calibration effort. This effort uses all JWST instruments to provide absolute flux calibration for all JWST modes (filters, gratings, etc). The combined nature of this effort is to ensure the highest quality flux calibration internal to and between instruments and to carry out the observations efficiently. This program provides observations of solar analog stars and companion programs provide observations of hot stars and A dwarfs observations. The absolute flux observations will be compared to model predictions of the stars' flux densities to calculate the appropriate calibration factors per instrument mode.

This program obtains repeated observations of two stars as part of the JWST absolute flux calibration effort. This effort uses all JWST instruments to provide absolute flux calibration for all JWST modes (filters, gratings, etc). The combined nature of this effort is to ensure the highest quality flux calibration internal to and between instruments and to carry out the observations efficiently. This program provides observations of two stars spread throughout the year to measure the repeatability of JWST observations. The aim is to observe in one filter/grating/etc per detector to measure how repeatable an observation is in instrument units. The expectation is that the repeatability is set at the detector level.

This proposal monitors the geometric distortion & pixel scale of both FGS Guide channels. The LMC astrometric field is imaged via FGS in calibration mode, obtaining full frame images at 5 different positions within the astrometric field for each of the two channels. The mid-point of the catalog will be placed at the center of the FGS channel being calibrated (the other channel will be guiding). This will ensure that (1) the same stars are used to calibrate FGS1 and FGS2, and (2) we will thus obtain an accurate measure of the relative sensitivity of Guiders 1 & 2.This program is similar to CAR-FGS-011.

This will monitor the flat field of the FGS channels. There is significant structure in the lamp flats, however, these lamp flat fields are good for monitoring trends in the response of the detector over time. The internal calibration lamp shall be used, so Fine Guiding will not be possible, hence ACS will be under coarse control. Exposures will use full frame images. Each exposure is repeated five times for cosmic ray rejection. After the full frame data are obtained, a 1 arcminute telescope offset is to be executed and the imaging sequence is to be repeated to allow for sky-source removal (the FGS has no shutter or opaque element).

This program obtains observations of A dwarf stars as part of the JWST absolute flux calibration effort. This effort uses all JWST instruments to provide absolute flux calibration for all JWST modes (filters, gratings, etc). The combined nature of this effort is to ensure the highest quality flux calibration internal to and between instruments and to carry out the observations efficiently. This program provides observations of A dwarf stars and companion programs provide observations of white and G dwarf observations. The absolute flux observations will be compared to model predictions of the stars flux densities to calculate the appropriate calibration factors per instrument mode.

This program obtains observations of white dwarf stars as part of the JWST absolute flux calibration effort. This effort uses all JWST instruments to provide absolute flux calibration for all JWST modes (filters, gratings, etc). The combined nature of this effort is to ensure the highest quality flux calibration internal to and between instruments and to carry out the observations efficiently. This program provides observations of white dwarf stars and companion programs provide observations of A and G dwarf observations. The absolute flux observations will be compared to model predictions of the stars flux densities to calculate the appropriate calibration factors per instrument mode.

This program obtains observations of A dwarf stars as part of the JWST absolute flux calibration effort. This effort uses all JWST instruments to provide absolute flux calibration for all JWST modes (filters, gratings, etc). The combined nature of this effort is to ensure the highest quality flux calibration internal to and between instruments and to carry out the observations efficiently. This program provides observations of A dwarf stars and companion programs provide observations of white and G dwarf observations. The absolute flux observations will be compared to model predictions of the stars flux densities to calculate the appropriate calibration factors per instrument mode.

This program obtains repeated observations of two stars as part of the JWST absolute flux calibration effort. This effort uses all JWST instruments to provide absolute flux calibration for all JWST modes (filters, gratings, etc). The combined nature of this effort is to ensure the highest quality flux calibration internal to and between instruments and to carry out the observations efficiently. This program provides observations of two stars spread throughout the year to measure the repeatability of JWST observations. The aim is to observe in one filter/grating/etc per detector to measure how repeatable an observation is in instrument units. The expectation is that the repeatability is set at the detector level.