2017-05-18 TrEX WG Meeting notes

Date

18 May 2017

Time

Item

Who

Notes

Simulated Data

Deadline is May 31st
Need Level1b data
- There is a tool available in the JWST pipeline called create_data that converts FITSWRITER files to DMS level 1b
- Convert FITSWRITER file to DMS level 1b
"Small" data sets in all TSO modes (simple, noise free)
"Medium" data set containing simulated transit with realistic uncertainties
"Large" data set for memory management and archival distribution purposes
Need matching APT files
See below for PDF of required header keywords
Place files on central storage
- /grp/jwst/dms/TSO
Everett presented update on NIRCam simulated data (see slides below)

Bright Target Acquisition (TA)

NIRCam TA uses medium filter (F335M) and NGROUPS=3
Saturation limit is K=7.02
4 GTO targets exceed this limit (HD 189733, HD 209458, HD 149026, GJ 436)
Implementation of a narrow filter for TA improves limit by ~2.5 mag, but won't likely be possible until Cycle 2
Option A: TA on offset target
- Positive: Requires no additional capabilities
- Negative: Limited to < 30" separation, requires both positions be know very precisely, faintness limits
Option B: TA on saturated target
- Positive: No offset uncertainty, better pointing consistency, doesn't require nearby offset star
- Negative: May require changes to flag saturated pixels
- John Stansberry to test how far into saturation we can reasonably go
- Faint offset targets aren't an issue, K=18.5 using DEEP8 and NGROUPS=65
Option C: Add TA through a narrow-band filter to APT and OSS
- Positive: Improves saturation limit to ~K=5.5
- Negatives:
  - Requires changes to APT, PPSDB, OPGS, OSS
  - May require separate 'apertures' to be defined for TA in the 2 filters (calibration issue).
Option D: Allow TA using NGROUPS=1, 2
- Positive: Improves saturation limit by ~1.2 mag
- Negative: Requires bigger changes to OSS than Option C, and APT changes (at least).

Proposal Instructions for JWST

Waiver for exposure limit on MIRI TSO imaging
Implement new Special Requirement "Time Series Observation" for some JWST templates
Sarah Kendrew working on table of TSO modes (mandatory, optional, not available), may include in JDox

JWST Documentation

Many JDox pages are going live tomorrow (May 19th)
Instrument team members should review relevant pages and supply feedback if changes are needed
Still working on TSO landing page that provides a broad overview and directs users to additional pages for more detailed information

Best NIRISS Observing Practices

Loic

Loic recommends using F277 filter to measure position of first order trace (without second order overlap)
Filter/grism combination not currently supported in APT for science observations
Loïc Albert to look into prioritizing this change with respect to other tasks