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SoloHI consists of 1 white-light telescope with wide FOV. However, data The image is captured on a mosaic of four 2048x1920 APS detectors that are read out independently. This gives flexibility for image operations: independent exposures, cadences, etc.). Data can be read out either from the whole detector or from well-defined subfields:
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selected subfields.
Typically, SoloHI images will have one of 3 typical FOVs defined below. These are used in the observing programs/modes currently defined but could be changed in-flight if necessary.
| FOV split (radial x transverse) | FOV (radial x transverse) | TM/raw image | compression ratesDownlinked pixels | Typical cadence | Comments | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| SoloHI Full frame image | 3968 (40ºx40º) | 5º to 45º x 40º | 1960 px * 3968 px | 5º-45º x 5º-45º (40ºx40º) | 1960 px | 24-36 min (inner FOV) |
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| SoloHI inner FOV subframe image | 192 px * 512 pximages (3 images of 1.88ºx5º) | 5.8º | -to 7.68º x 5º | (1.88ºx5º)
| -to 15.38º x 5º | -to 20.38º x 5º | 192 px * 512 px (not binned) | 18-36 sec | Subframe images typically only used at and near perihelion (up to 0.36AU) | ||
| Radial Swath subframe image | 3968 px * 512 px | 5º-45º x 5º (40ºx5º) | (40ºx5º) | 5º to 25º x 5º 25º to 45º x 5º | 1960 px * 256 px | 6 min (inner FOV) | Radial swath images typically only used at and near perihelion (up to 0.36AU) |
Observational modes
Main science programs
source: UM excerpt Jan 2015
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SoloHI UM - SSD-DOC-SOLOHI-013 Rev. B draft 5
The SoloHI baseline observing program will be defined to repeat for each occurrence of the same unique orbit (i.e. each orbit of the trajectory within the same resonance with Venus). Therefore, a SoloHI baseline observing program will be defined for each orbit phase in NMP/EMP and will be executed for all orbits within that resonance.
Example of such an orbit plan is below:
| Observing modes - Example plan | Use case | #images / day | Science data volume / day | SoloHI data rate | Observing duration / orbit | ||
|---|---|---|---|---|---|---|---|
| estimate (Gbits) estimate | (kbits/s) | (days) example | |||||
| Perihelion programs: | 0.28-0.29 AU | ||||||
SoloHI Solar Wind Turbulence @perihelion@perih | 1296 | 2.22 | 26.5 | 3 | |||
SoloHI Shock Formation @perihelionFormation @perih |
| 468 | 2.54 | 30.3 | 3 | ||
| Near-Perihelion programs: | 0.29-0.36 AU | ||||||
| SoloHI Near-perihelion Synoptic Program | 348 | 1.69 | 20.3 | 5 | |||
| SoloHI Solar Wind Turbulence Near-perihelion | 750 | 1.94 | 23.2 | 2 | |||
| SoloHI Shock Formation Near-perihelion | 516 | 2.45 | 29.3 | 2 | |||
| Far-Perihelion programs: | 0.36-0.42 AU | ||||||
| SoloHI Far-Perihelion Synoptic Program | 132 | 1.64 | 19.7 | 7 | |||
| Southern Latitude | |||||||
Southern  Out-of-ecliptic programs: | 0.5-0.7 AU | ||||||
| SoloHI Southern Synoptic Program | 104 | 0.84 | 10.3 | 8 |
Probably dependent Dependent on the trajectory
Examples of more-detailed observing program for 1 type of orbit during the mission (source: 04_130904_SoloHI_CDR_ObsProg.ppt):
Based on table above:
- a typical perihelion programme would produce ~25kbps (during 4 days), -> see modelled observations HI_SHOCK_PER (DATARATE=30300 [bits/sec]), HI_TURB_PER (DATARATE=26500 [bits/sec]),
- near-perihelion SoloHI would produce ~20kbps (during 8 days) , -> see modelled observation HI_SYN_PER (DATARATE=20300 [bits/sec])
- ~18.5kbps even further out (during 12 days) and -> see modelled observations HI_SYN_NEAR (DATARATE=19700 [bits/sec])
- in the far-out RSwindow, a datarate around 10 kbps would be reached. -> see modelled observations HI_SYN_FAR (DATARATE=10300 [bits/sec])
(see also SoloHI concept study report Dec 2011)
How to organize SoloHI observations in coordination with the other instruments, i.e. does SoloHI have 'observing modes' to choose from for each solar distance?, is still to be discussed in more detail. Also, while the schema above may be optimal from a science perspective, the varying downlink rate & SSMM storage limits may impose limitations on when which datarate can be used.