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Instrument Performance and Requirements



Jesper Schou

Stanford University

jschou@solar.stanford.edu

(650) 725-9826



Observing scheme

Instrument requirements

Instrument top level description



Observing Scheme



Observables

Dopplergrams

LOS magnetograms

Vector magnetograms

Intensity images

Etc.

Observables made from filtergrams

Ground processing only

Allows for calibration

Allows for reprocessing, if needed

Low complexity

High data rate



Filtergram properties

Wavelength

Polarization state

Camera, observing mode, exposure time, ...



Framelists

Basic list repeated during normal operations

45s Doppler / 90s magnetic

Data from two cameras not combined

Options for  wavelengths

Options for polarization scheme

1framelist.eps



Instrument Requirements



Observable requirements

              

Filtergram requirements

              

Instrument requirements

Spacecraft requirements















Requirements Traceability



General Requirements


&Angular resolution:&&Angular resolution:&&Aperture: 14cm &

&1.5(1)"&&1.5(1)"&&Jitter: 0.1" &

&&&0.5" pixels&&CCD pixels:&

&Full disk&&FOV: 2000" x 2000"&&4096&

&99 complete 95 time&&99.99 complete 95 time&&Packet loss: 0.01&




Continuum intensity


&Cadence: 50(45)s&&I framelist: 50(45)s&&CCD readout &

&Noise: 0.3&&Intensity noise: 0.3&&Full well: 125ke&

&Pixel to pixel accuracy: 0.1&&Flat field knowledge&&Offset pointing&



Numbers in () are goals. indicates TBD. Most numbers are 1.





Velocity requirements


&Cadence: 50(45)s&&V framelist: 50(45)s&&CCD readout &

&Noise: 25(13)m/s&&Intensity noise: 0.6(0.3)&&Full well: 30(125)ke&

&&&Filter width: 76 m&&Element widths&

&&&Small sidelobes&&7 elements&

&&&&&Element widths&

&Disk averaged&& repeatability: 0.3(0.03)m&&HCM repeatability:&

&noise: 1(0.1)m/s&&&&60(6)"&

&&&Exposure knowledge:&&&

&&&200(20)ppm&&Shutter: 50(5)s&

&&&Each cycle same 's&&Two cameras&

&&&Effective  knowledge:&&Orbit info&

&Absolute: 10m/s&& accuracy: 3m&&HCM accuracy: 10'&

&&&&&Filter uniformity, drift&

&Range: 6.5km/s&&Tuning range: 250m&&3 tuned elements&

&(and 3kG)&&Filtergrams @ 5 or 6 &&CCD readout&




Line of sight field requirements


&Cadence: 50(45)s&&LOS framelist: 50(45)s&&CCD readout &

&&&LCP+RCP each cycle&&LCP+RCP available&

&Noise: 17(10)G&&Intensity noise: 0.5(0.3)&&Full well: 40(125)ke&

&&&High effective Lande g&&FeI 6173 (g=2.5)&

&Zero point: 0.3(0.2)G&& repeatability:&&HCM repeatability:&
&&&0.18(0.12)m&&36(24)" or&
&&&&&No move LCPRCP&

&&&Exposure knowledge:&&&

&&&120(80)ppm&&Shutter: 30(20)s&

&Range: 3(4)kG&&Tuning range: 250m&&3 tuned elements&

&(and 6.5km/s)&&Filtergrams @ 5 or 6 &&CCD readout&




Vector field requirements


&Cadence: 600(90)s&&Vector framelist: 600(90)s&&CCD readout &

&&&4 states each cycle&&4 states available&

&Polarization: 0.3(.22)&&Intensity noise: 0.4(0.3)&&Full well: 70(125)ke&




Instrument Performance Document



Purpose

Capture derivations

Internal tests and calibration

HMI overview

Science and instrument overview

Observables requirements (Doppler, magnetic, ...)

Observables to filtergram flow

Details of derivations

Derived requirements (pixel size, filter width, ...)

Filtergram to instrument flow

Details of derivations

Derived requirements for each subsystem


2filtersc.ps













2optics2.ps