ESO DOI Service

• Leibundgut, Bruno [European Southern Observatory (ESO)]
• Bordelon, Dominic [European Southern Observatory (ESO)]
• Grothkopf, Uta [European Southern Observatory (ESO)]
• Patat, Ferdinando [European Southern Observatory (ESO)]

A statistical analysis of metrics probing the use of VLT instruments yields a perspective on the demand, productivity and impact of individual instruments. The trends in the usage of these instruments provide information that may be useful in determining the timing of potential future instrument upgrades and replacements. We look at the evolution of observing time requests on VLT instruments; this is measured using the number of proposals submitted each semester as well as the requested time. We also look at the publication statistics on all VLT instruments and find that the older workhorse instruments have produced over 1000 publications to date. The most successful VLT instruments produce over 80 publications per year. After an initial increase as they enter operation, most instruments reach a constant rate of publications after between four and eight years and the number of publications and citations only starts to decline after decommissioning. We find that all instruments currently operating show increasing citation counts every year. ESO has regularly upgraded instruments to strengthen their scientific impact.