eis calibration and operation
DESCRIPTION
EIS Calibration and Operation. H. Hara NAOJ. Calibration on the ground. Component-level calibration - Multi-layer mirror reflectance - Multi-layer grating efficiency - Filter transmissions - CCD camera calibration - FMIR position accuracy for raster scan - PowerPoint PPT PresentationTRANSCRIPT
EIS Calibration and Operation
H. Hara
NAOJ
Calibration on the ground• Component-level calibration
- Multi-layer mirror reflectance- Multi-layer grating efficiency- 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: 47mA long band: 58mA
- Primary mirror focus check- Grating focus check
Published in Seely et al. 2004, App. Opt., 43, No7,1463
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 sun-synchronous 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)
Science
-Team core science-Initial science targets-Proposal from users
Preparation for EIS SO
Check of Obs. Tableusing PM
Observationin orbit
Downlink stationsJAXA data storage
DataReformat
EGSE
Data check
- Obs. table- S/C CMDs
Analysis
Outcome
ISACS-PLN
Uplink station
Spacecraft
Merging EIS SO in S/C operation
EIS Planning
EGSEFinal S/C plan
ObservationPlanning
Data for analysisLevel0 dataLevel1 dataLevel2 data
Telemetry
Plan approvedfor EIS operation
Data centers
Users
FeedbackLine selectionExp. durationCompressionFOV size etc.
Data rate
Compression
Instrument CAL
Feedback
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).
END
EIS Calibration Spectrum 2" slit
Al III, Al IV and Ne IV lines
• 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
EIS Effective Area
EIS Science Targets
Active region/Flares
Quiet Sun/Network brightening
Limb/beyond the limb
Coronal HoleCoronal Hole Boundary
Bright Point
Polar Plume
Data RateCCD1 CCD0
CCD readout
Software window (SW)
Assemble all SWs EIS data size to MDP= total sum of software windows = (window width)i * (window height)i
height
MDP
JPEG
DPCM
Compression ratio = compressed data size/ input data size to MDP
Data rate ~ [EIS data size to MDP] * [Compression Ratio] / Cadence
EIS data of CCSDS format
EIS Data Flow
2Mbps max1.3 Mbps
CCD Readout Electronics EIS ICU
Large hardware CCD window
S/C MDP
Small spectral window (25 max)
Data compressionDPCM(loss less) or 12bit-JPEG
260 kbps max for short duration, 45 kbps average
Telemetrydata format
Average rate depends on number of downlink station.
1 slit obs. 40 slot obs. 250 slot obs.Spec.width 16 40 250Spatial width 256 512 256No. of lines 8 4 4Compression* 25% 20 % 20%Cadence 3 sec 6 sec 20 secRate 42.7 kbps 42.7 kbps 40 kbps
13 min cadence for 44 rastering
Observation tablecontrol
* for 16 bit/pixel data
EIS Observation Sequence
OBS1 OBS2 OBS3 OBS4 OBS5
StopUpload new plan
Start
On-board S/C commands Stop Change SEQ
Start
Time
Datarate
Uplink commands
StopChange SEQStart Stop Change SEQ
Start
EIS Observations
40" slit raster
2" slit raster
1" slit raster
266" slit raster(no mirror motion)
An example of 240" 240" FOV240 "
240
"
Contribution of other emission lines
Wider instrumental width
EUV imaging of less contaminationby other lines
Discontinuous raster
MDP JPEG Compression
AR spectrum for 5 sec integration
Fe XII
Fe XI
Fe XXIVFe XII
Ca XVII
Fe XII
Fe XII
Fe XIII
Fe XIII
He IIFe XVI
Fe XIV
Fe XIV
Fe XV
224 pixels
256 pixels
JPEG compression errorX: signal – offset [DN] ; offset~ 500Y: decomp( comp( Original ) ) – Original [DN] DN17nm DN29nm
Compression Error for Q=85
Diff/ I Diff/ v Diff/ FWHM
v
original original original
FWHMI
= = =
Compression ratio = 0.19