The European Solar Telescope (EST)



Design study




EST performances requirements

4.2.1 Field of view 2´x2’ (goal 3´x3’). 3’x3’ Mosaic mode with optimal resolution in 1’x1’ patches NOT CONSIDERED FOR OPTICAL DESIGN (implies moving the telescope FoV)
4.2.2 Total throughput >10% (30% telescope; 30% instruments)
4.2.3 Wavelength coverage 390nm to 2.3μm (goal 350 nm to 2.3μm) with AO correction (Coudé focus) 315 nm to 20 μm without AO (Nasmyth focus)
4.2.4 Light distribution Configurable with different fractions of light going to different instrument channels
4.2.5 Photon flux > 2.106 photon/(pixel·s) instrument detector plane
4.2.6 Polarimetric sensitivity 3.10-5 in S/I, S any stokes parameter
4.2.7 Polarimetric accuracy Accuracy to know crosstalk between Stokes parameters
4.2.8 Scattered light at 500nm < 10 % at 1” distance from the scattered light source on the science focal plane,
< 1% at 5” distance
Coronal observations, flux from the observed line >1 ADU before the background saturates detector
4.2.9 Sky coverage Ecliptic above 10º on the horizon (goal full sky)
4.2.10 Observable radius away from the Sun 200” from the solar limb   >5 º (goal >2º) away from the Sun avoiding solar illumination
4.2.11 Image stability 0.004”/10s (goal 0.003”/10s) with closed loop AO.
0.05arcsec/10s without closed loop AO
4.2.12 Image scanning step Time<0.1s
4.2.13 Image scanning repeatability 0.002´´ Spectrographs 1” (TBC) mosaic mode for BB and NB imagers
4.2.14 mage scanning stability 0.01” over 1 hour
4.2.15 Absolute pointing accuracy <3”
4.2.16 Open loop tracking accuracy <1” /10minutes
4.2.17 Image quality with closed loop MCAO SR500nm=0.3 (TBC) for 1´FoV and SR500nm=0.4 (TBC) for 30”FoV for r0>20cm.
SR500nm=0.15 (TBC) for Ø1´FoV and SR500nm=0.25 (TBC) for Ø30”FoV for r0>10cm
4.2.18 Closed loop MCAO for near-limb observations AO low order mode for observations near the limb, using Hα images. Performances TBD
4.2.19 Image quality without closed loop AO Image quality degradation <10% seeing conditions for good seeing conditions (r0 =20cm at 500 nm)
4.2.20 Data flow Data flux 200GB/sec Data volume 275PB/year
4.2.21 Maximum time between image acquisitions in mosaic mode 2s for contiguous subfields
6s for non contiguous subfields

(Table from L. Cavaller (IAC & GranTeCan) & the EST project)