CIRSGSFC April 2004 dej-1 CIRS Instrument Overview CIRS Team Meeting Observatoire de Paris - Meudon April 26 – CIRS Instrument Group presented by Don Jennings CIRS Instrument Overview

CIRSGSFC April 2004 dej-2 Instrument Operations/Performance Overview

CIRSGSFC April 2004 dej-3 Instrument Operations/Performance Overview  All aspects of instrument performance and functional operations working well – Thermal stability, lasers, interferometers, cooler, arrays  Performance re calibration parameters (response, instrument emission, NESR) essentially same as measured during ground testing in the instrument development phase  Instrument performance was fully checked in 24 hr calibration test Sept Includes array’s performance at 5 focal plane temperatures. Results posted to WEB.  Saturn approach phase C43 sequence covers Feb 20 – April 1, 2004; Saturn angular diameter less than 2.5 mrad

CIRSGSFC April 2004 dej-4 C43 - Optics Assembly Temperatures

CIRSGSFC April 2004 dej-5 C43 – Primary Mirror Temperatures

CIRSGSFC April 2004 dej-6 C43 – OA Operational Heater Powers

CIRSGSFC April 2004 dej-7 C43 - Cooler FPA Temperatures

CIRSGSFC April 2004 dej-8 FP1 Chronological Response Summary - Unapod

CIRSGSFC April 2004 dej-9 FP3_5 Chronological Response Summary - Unapod

CIRSGSFC April 2004 dej-10 FP4_6 Chronological Response Summary - Unapod

CIRSGSFC April 2004 dej-11 Saturn Calibration Status

CIRSGSFC April 2004 dej-12 Saturn – ISS Image 12 Mar 2004

CIRSGSFC April 2004 dej-13 Saturn Calibration – Calibration Data Acquisition Guidelines  FPA Setpoint Temperature: Run at lowest temperature possible for maximum sensitivity of FP3 and FP4 arrays. In approach phase, running mainly at 75.5K, plus occasionally at 76.3K. Need to get through first few orbits for full test of environmental fluxes on cooler before trying to standarize on one base FPA temperature. For reference, Jupiter FPA temps were 76.3, 77.0, 77.7K.  Acquire adequate deep space and shutter calibration data within given science sequences. Essential if instrument is not in full thermal equilibrium due to sun on instrument radiators, etc.

CIRSGSFC April 2004 dej-14 FP3: Avg Response and Instrument Emission for Ten Detectors

CIRSGSFC April 2004 dej-15 FP3: NESRs for Average of All Ten FP3 Detectors

CIRSGSFC April 2004 dej-16 FP4: Avg Response and Instrument Emission for Ten Detectors

CIRSGSFC April 2004 dej-17 FP4: NESRs for Average of All Ten FP4 Detectors

CIRSGSFC April 2004 dej-18 Saturn Calibration – Calibration Datasets Three types of calibration data:  DSCALs – Specific calibration sequences of 3 – 6 hrs duration, obtained during downlinks (usually rolling).  Internal to science sequence – Deep space and shutter closed data obtained within a science sequence.  Shutter closed data only – Serves as a relative monitor of internal optics assembly temperature changes. Can not directly be used in calibration without associated deep space data

CIRSGSFC April 2004 dej-19 Pipeline Status – Changes Needed for “Routine” Automated Calibration  Saturn calibration presently frozen. Need following changes:  S/C Navigation Data – Finish algorithms for automated nav data acquision from JPL, and automated conversion to Vanilla parameters. This data is a prerequisite to calibration; s needed to establish deep space spectra within a science sequence. For Jupiter, the criteria was that all data more than two fov’s from the edge of a target was deep space. This criterion needs to be reviewed for Saturn, rings, Titan, icy satellites. Work is needed to identify the deep space spectra within the rings sequences.  Calibration algorithm for FP3 and FP4 arrays – Modify algorithm in order that calibration is accomplished with science and calibration data obtained with the same FPA temperature, pixel combination, coadd/noadd, RTI. This criterion is most troublesome for 0.5 cm -1 data; may need to go 1-2 months either side of the science data to achieve this. Only part of this was implemented for Jupiter.

CIRSGSFC April 2004 dej-20 Pipeline Status – Changes Needed for “Routine” Automated Calibration (Con’t)  Calibration data blocks – Establish the minimum number of deep space spectra needed for averaging a calibration data block plus the time period needed to acquire this block.  Spikes (8 Hz, 1/2 Hz, others?) – Most relevant to 400 and 224 RTI data. Too many spikes, amplitudes too large, some durations large (3- 5 words). Calibrated spectra not really useable. Lower resolution data may be ok to first order. Spikes preventing us from reaching detector noise level.  Sine wave interference in FP1. Variable in frequency and intensity. Frequency varies with electronics temperature; range is cm -1, usually below 100 cm-1.

CIRSGSFC April 2004 dej-21 Change in Spike Period

CIRSGSFC April 2004 dej-22 Saturn Observed Spectrum FP3_5 – March 2004

CIRSGSFC April 2004 dej-23  Saturn Obs Spec FP3_5 – March 2004, with noise

CIRSGSFC April 2004 dej-24 Saturn Obs Spec FP3_5 – March 2004, with noise

CIRSGSFC April 2004 dej-25 Saturn Ring Spectrum (from Conor Nixon)

CIRSGSFC April 2004 dej-26 Saturn Observed Spectrum FP4 – 14 Feb 2004

CIRSGSFC April 2004 dej-27 Saturn Observed Spectrum FP4_6 – March 2004

CIRSGSFC April 2004 dej-28 Interference in Co-add Interferograms

CIRSGSFC April 2004 dej-29 Interference in No-add Interferograms

CIRSGSFC April 2004 dej-30 Jupiter Calibration Status

CIRSGSFC April 2004 dej-31 Jupiter Calibration Status  Spectral calibration accomplished.  Global calibration of FP1 awaiting pipeline implementation.  Global calibration of FP3 in progress.  Changes in pipeline calibration algorithms were needed for both Jupiter and Saturn. Will now be implemented for Saturn first.  Little to no work on Jupiter calibration in last 3-4 months. Lower priority than tour programming changes in health and safety, tour data handling programming, preparation of approach phase calibration sequences, monitoring of downlinked approach phase data.

CIRSGSFC April 2004 dej-32 Sine Wave Interference  Sine wave was missed during Jupiter encounter. Seen when we examined individual Saturn interferograms.  Originally seen in ICO 1. Always present at some level.  Varies in frequency between 600 and 0 cm -1 ; usually below 100 cm - 1. Drifts with electronics temperature, but cause unknown.  Phase not correlated with ZPD (different from BIU spikes). Amplitude varies somewhat.

CIRSGSFC April 2004 dej-33 Sine Wave Interference (cont’d)  In Jupiter data, phase drift caused cancellation in large averages, so problem was not recognized.  Frequency approaches 0 cm -1 as electronics temperature stabilizes.  Adds spurious structure to cm-1 region.  Ideally, should be removed from individual interferograms in data reduction, possibly by fitting and removing.

CIRSGSFC April 2004 dej-34 Interference in FP1 at Jupiter

CIRSGSFC April 2004 dej-35 Sine Wave Frequency vs Electronics Temp

CIRSGSFC April 2004 dej-36 Electronics Temperature at Jupiter Sine wave Frequency (cm-1)

CIRSGSFC April 2004 dej-37