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Table 16.

Characteristic requirements of the Metis observing modes.

Mode FoV (a) Binning (pixel) NPOL(b) DIT (c) TACQ(e) TEXP(g) TCAD(h) CR removal (i) CME flag (m) Compression ratio (n) Data volume (o)
(≤2.5°) (> 2.5°)
WIND VL 1.7–5 R⊙ 2 × 2 4 × 4 4 15–20 s =DIT 75–450 s 5–30 min YES ON 21 16.14 Mb
UV 2 × 2 – 1–60 s (d) 1–600 s (f) 5–30 min 5
MAGTOP VL 1.7–5 R⊙ 2 × 2 4 15 s =DIT 75–300 s 5–20 min YES ON 13 26.67 Mb
UV – 1–60 s 1–600 s 5–20 min 3
(≤2.5°) (> 2.5°)
GLOBAL VL 1.7–3 R⊙ 2 × 2 4 × 4 4 15–30 s =DIT 75–450 s 5–30 min YES ON 21 13.73 Mb
(0.28 AU) UV – 1–60 s 1–600 s 5–30 min
(≤2°) (> 2°)
GLOBAL VL 4–7.5 R⊙ 2 × 2 4 × 4 4 15–30 s =DIT 75–450 s 5–30 min YES ON 31 9.21 Mb
(0.7 AU) UV – 1–60 s 1–600 s 5–30 min
LT-CONFIG VL 1.7–3 R⊙ 4 × 4 4 15–30 s =DIT 300–450 s 20–30 min YES ON 51 5.70 Mb
(0.28 AU) UV – 1–60 s 1–600 s 20–30 min
LT-CONFIG VL 4–7.5 R⊙ 4 × 4 4 15–30 s =DIT 300–450 s 20–30 min YES ON 51 5.70 Mb
(0.7 AU) UV – 1–60 s 1–600 s 20–30 min
FLUCTS VL 1.7–3 R⊙ 2 × 2 1 1 s =DIT 1 s 1 s NO OFF 13 5.34 Mb
(0.28 AU)
TBF VL 1.7–3 R⊙ 2 × 2 2 20 s =DIT 20 s 20 s NO OFF 13 5.34 Mb
(0.28 AU)
CMEOBS VL 1.7–9 R⊙ 2 × 2 4 15 s =DIT 15–75 s 1–5 min YES/NO (l) OFF 13 26.67 Mb
UV – 1–60 s 1–600 s 1–5 min 3
COMET VL 1.7–9 R⊙ 2 × 2 4 15–20 s =DIT 75–300 s 5–20 min YES ON 13 26.67 Mb
UV – 1–60 s 1–600 s 5–20 min 3
PROBE VL 1.7–9 R⊙ 2 × 2 4 15–30 s =DIT 75–450 s 5–30 min YES ON 13 22.69 Mb
UV – 1–60 s 1–600 s 5–30 min

Notes.

(a)

The FoV spans over a wide range of heliocentric distances owing to the spacecraft eccentric orbit, although only part of this range is accessible at the same time.

(b)

Number of polarisation angles used (cycled) during the scientific VL measurement.

(c)

Detector Integration Time, representing the actual exposure time of a single read out of the detector frame.

(d)

In Photon Counting mode the typical DIT is 97 ms.

(e)

Acquisition time, the overall integration time corresponding to a single acquisition. The integration values are set in order to get a limited number of spurious events (cosmic rays) to be removed.

(f)

Values valid in Analogue mode only.

(g)

Exposure Time, i.e. the overall time corresponding to a single exposure. Single acquisitions are averaged over the exposure time interval, unless a CME flag occurs. Exposure times are determined considering the count-rate estimated for the Sun at its minimum of activity.

(h)

Cadence, i.e., time required to get a full set of 4 VL science images or 1 UV science image.

(i)

Software procedure to remove CRs and SEPs spurious signals.

(l)

Disabled if the number of acquisitions (NACQ) is equal to 1; it is enabled if NACQ >  1.

(m)

CME detection algorithm.

(n)

Resulting from the combination of the selected binning and masking options with the reduction performed by the compression algorithm, assumed lossless.

(o)

For a full set of 4 VL science images plus 1 UV science image. In the case of the “FLUCTS” and “TBF” modes, 1 VL science image only.

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