ESPRESSO's Early Commissioning Results and Performance Related to Tests of Fundamental Constant Stability

Understand

ESPRESSO is a new high-resolution ultra-stable spectrograph for the VLT, which had its first light on Telescope on November 27th, 2017.

• The instrument is installed in the Combined Coud\'{e} Laboratory and linked to the 4 Units of Telescope through optical Coud\'{e} Trains, being the first spectrograph able to collect the light from the 4 UTs simultaneously.
• One of the key science goals of the instrument is to test the stability of nature's fundamental couplings with unprecedented resolution and stability.
• ESPRESSO will allow to eliminate current known systematics and test the claim by Webb et al 2012 of a spatial dipole in the variation of the fine-structure constant.