ESPRESSO (Echelle SPectrograph for Rocky Exoplanet- and Stable Spectroscopic Observations) is a new-generation, high-resolution, fiber-fed and cross-dispersed echelle spectrograph (R = 140,000) for the visible wavelength range (350 nm – 720 nm), for the European Southern Observatory's Very Large Telescope. Its main feature is the spectroscopic stability and the radial velocity precision. With incredible spectroscopic precision, it will be able to detect Earth-like planets. For example, our Earth induces a radial-velocity variation of 9 cm/s on our Sun.[1]
The requirement is to reach 10 cm/s, but the aimed goal is to obtain a precision level of a few cm/s. Installation and commissioning of ESPRESSO at the VLT is foreseen in 2016.[1]
The instrument is capable of operating in 1-UT mode and in 4-UT mode. In 4-UT mode, in which all the four 8-m telescopes are connected incoherently to form a 16-m equivalent telescope the spectrograph will reach extremely faint objects.[1]
Contents |
For example (for G2V type stars):
| ESPRESSO | CODEX | |
|---|---|---|
| Telescope | VLT (8m) | E-ELT (42m) |
| Scope | Rocky Planets | Earth-Like |
| Sky Aperture | 1 arcsec | 0.80 arcsec |
| R | 150000 | 150000 |
| λ Coverage | 350-730 nm | 380-680 nm |
| λ Precision | 5 m/sec | 1 m/sec |
| RV Stability | < 10 cm/s | < 2 cm/s |
| 4-VLT mode (D=16m) with RV=1m/sec |
Ref:[2]