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