EIS Calibration and Operation H Hara NAOJ Calibration
EIS Calibration and Operation H. Hara NAOJ
Calibration on the ground • Component-level calibration - Multi-layer mirror reflectance Published in - Multi-layer grating efficiency Seely et al. 2004, App. Opt. , 43, No 7, 1463 - Filter transmissions - CCD camera calibration - FMIR position accuracy for raster scan - CMIR mechanism position accuracy for FOV setting • Instrument-level calibration - Effective area calibration: preliminary one is in SSW - Wavelength calibration - Instrumental width in emission lines short band: 47 m. A long band: 58 m. A - Primary mirror focus check - Grating focus check
On-Orbit Calibration • On-Orbit calibration - Cross-check of effective area by using density insensitive line ratio - Wavelength calibration in an orbit - Estimation of contamination and degradation - Estimation of absorption by Earth’s atmosphere in low-altitude sunsynchronous orbit - Check of MDP compression (DPCM/JPEG) performance using the actual solar spectra/images. - Calibration rocket flight planned (EUNIS) by NASA GSFC group
EIS Science Operation (SO) -Team core science -Initial science targets -Proposal from users Outcome EIS Planning EGSE Observation Planning Science Feedback Preparation for EIS SO Feedback Line selection Exp. duration Compression FOV size etc. Analysis Data rate Compression Instrument CAL Data check Users - Obs. table - S/C CMDs ISACS-PLN Plan approved for EIS operation Check of Obs. Table using PM Data for analysis Level 0 data Data Level 1 data Level 2 data Reformat EGSE Data centers Merging EIS SO in S/C operation JAXA data storage Final S/C plan Uplink station Spacecraft Telemetry Observation in orbit Downlink stations
Summary • Deep understanding of the Calibration Issues and Science Operation leads to good science. For easy analysis knowledge of calibration will be installed in EIS analysis software. • Various observations can be performed with the EIS Sequence structure (EIS observation table).
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EIS Calibration Spectrum 2" slit • Calibration is being carried out with the source used for SOHO CDS calibration (Hollandt et al. , 2002, Lang et al. , 2000) • Source is a secondary standard radiometrically calibrated by PTB, Berlin at the BESSY I electron storage ring • Stable high-current hollow-cathode discharge lamp provides appropriate EUV emission lines • Following EIS calibration, the source will be re-calibrated at BESSY II Al III, Al IV and Ne IV lines
EIS Effective Area
EIS Science Targets Bright Point Limb/beyond the limb Active region/Flares Quiet Sun/ Network brightening Coronal Hole Boundary Coronal Hole Polar Plume
Data Rate CCD 1 CCD 0 CCD readout height Software window (SW) EIS data size to MDP = total sum of software windows = (window width)i * (window height)i Assemble all SWs MDP DPCM EIS data of CCSDS format JPEG Compression ratio = compressed data size/ input data size to MDP Data rate ~ [EIS data size to MDP] * [Compression Ratio] / Cadence
EIS Data Flow CCD Readout Electronics Large hardware CCD window Small spectral window (25 max) EIS ICU 2 Mbps max 1. 3 Mbps control Observation table 1 slit obs. 40 slot obs. 250 slot obs. Spec. width 16 40 250 Spatial width 256 512 256 No. of lines 8 4 4 Compression* 25% 20% Cadence 3 sec 6 sec 20 sec Rate 42. 7 kbps 40 kbps * for 16 bit/pixel data 13 min cadence for 4 4 rastering Data compression DPCM(loss less) or 12 bit-JPEG S/C MDP 260 kbps max for short duration, 45 kbps average Average rate depends on number of downlink station. Telemetry data format
EIS Observation Sequence On-board S/C commands Stop Change SEQ Start OBS 1 Stop OBS 2 OBS 3 Change SEQ Stop Start Stop OBS 4 Start Upload new plan Uplink commands Data rate Time Change SEQ Start OBS 5
EIS Observations An example of 240" FOV 1" slit raster Discontinuous raster 240 " 2" slit raster Wider instrumental width 40" slit raster 266" slit raster (no mirror motion) EUV imaging of less contamination by other lines Contribution of other emission lines
MDP JPEG Compression AR spectrum for 5 sec integration Fe XII 256 pixels Fe XII Fe XXIV Ca XVII 224 pixels Fe XV Fe XIII Fe XVI Fe XIV He II Fe XIV
JPEG compression error X: signal – offset [DN] ; offset~ 500 Y: decomp( Original ) ) – Original [DN] DN 17 nm DN 29 nm
Compression Error for Q=85 Compression ratio = 0. 19 v I original Diff/ I = FWHM original Diff/ v = original Diff/ FWHM =
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