1. Feb 4, 20034th Solar-B Science Meeting1 SOT Scientific Observations & Operations T. Shimizu (National Astronomical Observatory of Japan) Shimizu@solar.mtk.nao.ac.jp Purpose: Look at SOT observational capabilities from operational viewpoints Some slides from Dr. T.Tarbell presented at 3 rd science meeting

2. Feb 4, 20034th Solar-B Science Meeting2 SOT On-board Operations Scientific data are produced by Focal Plane Package (FPP) in SOT Observational sequence is controlled by SOT observation table in MDP FPP as a slave Users update only the SOT observation table for their observations Macro-command (MC) for taking a science data (observable) MDP Observation table (sequence) FPP Observation (observable generation) MC Solar-B

3. Feb 4, 20034th Solar-B Science Meeting3 SOT Observation Table in MDP Consists of FG table and SP table, which work independently each other ProgramTable (Main routine) calls Subroutines which call Sequences which are lists of macro-commands and commands 20 programs Main routine Obs. Program Subroutines 100 sequences Sequence /w repeat # interval /w interval

4. Feb 4, 20034th Solar-B Science Meeting4 Macro-commands For taking a science data (observable) Contain the following parameters which SOT chief observers may set up Compression Parameters - MDP bit compression - MDP JPEG/DPCM compression Operational Parameters FG Extract Region or SP Map Region Parameters - Defining type of data (observable) (ex. Magnetogram,…) - CCD/exposure setup (ex. size, binning, exposure duration) - Wavelength setup (ex.   offset) etc

5. Feb 4, 20034th Solar-B Science Meeting5 Variety of SOT Data SOT Scientific Data (Observables) from FPP Filtergraph (FG) Camera Stokes-Polarimeter (SP) Camera Filtergrams Longitudinal Magnetograms Dopplergrams Stokes I/Q/U/V images Stokes Map Solar-B MC (Macro-command) Issued from MDP observation tables (FG table and SP table) Broadband filter (G band, continuums etc) Narrowband filter (H  ), dark frame etc

6. Feb 4, 20034th Solar-B Science Meeting6 FG Camera Observables: Filtergrams G-band 4305 H  center Solar-B Filtergrams 2-D spatial data (a snapshot image) Size (typical): 2K x 4K pixels (max) 2K x 2K 1K x 1K 0.5K x 0.5K (from combination of FOV size + pixel sum) Full size FOV: Broadband filter 164”x328” Narrowband filter 109”x218” Pixel sum: 1x1(full), 2x2, 4x4

7. Feb 4, 20034th Solar-B Science Meeting7 FG Camera Observables: Filtergrams Solar-B Filtergrams Wavelength (typ.) - Broadband filter (6) CN I 3883, CaII H 3969, CH I 4305, Continuum 4505 Continuum 5551, Continuum 6684 - Narrowband filter various positions in H  6563, HeNe, (and bands including lines mainly used for Magneto/Dopper-grams) - Dark frame scan filtergrams (X x Y pixels) x N (N= # of scan)

8. Filtergrams (NFI & BFI) Shutter open/close always synchronized with Polarization Modulator Exposure times 0.1 - 1.6 sec in NFI,.03 -.8 sec in BFI (longer exposures possible if desired) Full readout in 3.4 sec, 2x2 summing in 1.7 sec, 4x4 summing 0.9 sec Partial readout possible for faster cadence & reduced data volume: several discrete sizes from 192 to 2048 rows Reconfigure time (filterwheels, TF) < ~2.5 sec No onboard processing in FPP, optional data compression in MDP

9. Feb 4, 20034th Solar-B Science Meeting9 FG Camera Observables: Magnetograms Solar-B Longitudinal Magnetograms 2-D spatial data generated on-board from multiple exposures Maps of Stokes V / Stokes I –Using multiple wavelengths reduces errors caused by Doppler shifts –Processing onboard combines many images into two (numerator & denominator) for reduced telemetry requirement

10. Feb 4, 20034th Solar-B Science Meeting10 FG Camera Observables: Magnetograms Solar-B Longitudinal Magnetograms Size (typical): 1K x 2K x N (smart memory limit) 1K x 1K x N 0.5K x 0.5K x N (N= 2 [Magnetogram V and I]) or 1) (from combination of FOV size + pixel sum) Primary lines are Fe I 6302.5 (photosphere) and Mg I 5172.7 (low chromosphere) –5250.2, 5250.6, 5247.1, 6301.5, 6303.8 (umbral) are also available –6302 Mgram with 0.08 arcsec px takes ~21 sec for 8 images (4 wavelengths) with 164x164 arcsec FOV, has rms noise of ~1.E15 Mx on a pixel –With 0.16 arcsec px, takes 12.8 sec and has rms noise ~2.E15 Mx

11. Feb 4, 20034th Solar-B Science Meeting11 FG Camera Observables: Dopplergrams Solar-B Dopplergrams

12. Maps of line-of-sight component of velocity –Baseline is simplified version of algorithm used by MDI instrument on SOHO –Derive central wavelength from 4 images uniformly spaced through the line, F1... F4 –R = (F1 + F2 - F3 - F4) / (F1 - F2 - F3 + F4) –Velocity = V(R), implemented on the ground by lookup-table –Use 2 smart memories to make numerator & denominator –Gain and offset variations of CCD cancel out –MDP performs compression & downlink Best photospheric line is Fe I 5576 (non-magnetic, g=0) –1-sigma noise of 30 m/s with 4 images, 2x2 summing, 0.16 arcsec px, 0.8 sec exposure, 240,000 electrons/px, 12.8 sec total time –1-sigma noise of 45 m/s with 0.08 arcsec px, 1.6 sec exposure Low chromospheric velocity can be measured in core of Mg I 5173 line –Very dark line, but higher velocities expected –1-sigma noise ~ 100 m/s with 0.16 arcsec px, 1.6 sec exposures

13. Feb 4, 20034th Solar-B Science Meeting13 FG Camera Observables: Stokes Solar-B Stokes IQUV A set of 2-4 different images of 2-D spatial data generated on-board from multiple exposures Size (typical): - Shuttered exposures 1K x 1K x N pixels 0.5K x 0.5K x N - Shutterless exposures 1K x 256 x N 1K x 128 x N (N= 4 or 2) (from combination of FOV size + pixel sum) Wavelength (typ.) Mg Ib 5173, Fe I 5247, Fe I 5250, Fe I 5251, Fe I 6302, Fe I 6303, Ti I 6304 Integration # of Exposures Stokes IVStokes IQStokes IU

14. Stokes Parameters Shutterless imaging with FOV restricted by focal plane mask –0.1 sec exposure and readout time: IQUV all measured simultaneously FOV = 5.3 x 164 for 0.08 arcsec pixels, 14.7 x 164 for 0.16, 35 x 164 for 0.32 Processing in smart memories identical to that for SP, to make spatial maps of I, Q, U, and V –0.2 sec exposure and readout time: IQV or IU, measured separately FOV = 10.7 x 164 for 0.08 arcsec pixels, 29 x 164 for 0.16, 70 x 164 for 0.32 Measure I & Q first, then I & U by shifting phase of exposure wrt Pol. Mod. –0.4 sec exposure and readout time: IV only FOV = 21 x 164 for 0.08 arcsec pixels, 58 x 164 for 0.16, or 140 x 164 for 0.32 Stokes Parameters using shutter –Up to 0.4 sec exposures possible for V, up to 0.2 sec for Q & U –Additional noise sources due to time between frames & cross-talk between polarizations will appear

15. Feb 4, 20034th Solar-B Science Meeting15 SP Camera Observables Solar-B Stokes Map Size (typical): One Stokes: 1K x 224 pixels Map: 1K x 224 x 2K pixels 896M bytes (without compression) 135M bytes (15% compression) Integration # of Exposures Map center position and # of slit scan positions Slit scan step size/pixel binning & slit scan summation Tip-tilt mirror (CTM) reset, repeat observation Scanning step (1~2K) IQ UV 1024 (max) 112 or 224 (/w orthogonal) 4 images at one scan position generated from multiple exposures (typically 48) Wavelength Fe I 6302 & 6303

16. Feb 4, 20034th Solar-B Science Meeting16 Spectro-Polarimeter Observing Modes (1 of 2) Normal Observing Mode –Expose/Read/Demodulate for 3 full rotations of waveplate, producing polarimetric accuracy of 0.001 –Optionally, move the slit-scanning mirror one step of 0.16 arcsec in the solar image (this takes 0.1 or 0.2 sec ==> 5.0 sec cycle) –Raw data is 120 x 2 spectral pixels x 1024 spatial pixels x 4 Stokes parameters in 4.8 sec, which is 983 Kpixels or 205 Kpixels/sec –Send to MDP for optional compression and downlink –Maps area 1.6 arcsec wide in 50 sec or 160 arcsec wide in 83 min. Fast Map Mode –Expose/Read/Demodulate for 1 full rotation of waveplate, step the slit 0.16 arcsec, Expose/Read/Demodulate for a 2nd rotation, adding to the previous results –Sum 2 pixels in spatial direction on chip ==> effective pixel size is 0.32 x 0.32 arcsec –Raw data rate is 492 Kpixels in 3.6 sec = 137 Kpixels/sec –Maps area 1.6 arcsec wide in 18 sec, and 160 arcsec in 30 min

17. Feb 4, 20034th Solar-B Science Meeting17 SP Observing Modes (2 of 2) In any mode, Field-of-View and data rate can be restricted by sending to the MDP only spectra from a limited spatial portion of the slit Dynamics Mode –Expose/Read/Demodulate for only 1 full rotation of waveplate –Optionally step the slit by 0.16 arcsec –Must limit spatial FOV to reduce data rate: maybe 32 arcsec typical slit length –Process as before –For 32 arcsec along the slit, raw data rate is 192 Kpixels in 1.6 sec or 120 Kpixels/sec Deep Magnetogram Mode –Expose/Read/Demodulate for many full rotations of waveplate –Goal is to detect weakest polarization signals possible –Ignore wrap-around of intensity and strong polarization signals –Downlink data with no compression to avoid artifacts from wrap-around boundaries

18. Feb 4, 20034th Solar-B Science Meeting18 SW Tools for Observation Planning SOT chief observers need SW tools to make macro- commands & program/sequence tables (or reuse existing ones in the database) to carry out a scientific observation Detailed design/task sharing is under discussion An example for macro-command editor used now in FPP flight-model test

19. Feb 4, 20034th Solar-B Science Meeting19 For editing SP macro-commands

20. Feb 4, 20034th Solar-B Science Meeting20 For FG macro-command