On-sky measurements of atmospheric dispersion – II. Atmospheric models characterization

Differential atmospheric dispersion is a wavelength-dependent effect introduced by Earth's atmosphere that affects astronomical observations performed using ground-based telescopes. It important, when observing at zenithal angle different from zero, to use an Atmospheric Dispersion Corrector (ADC) compensate this dispersion. The design of ADC based on models that, the best our knowledge, were never tested against on-sky measurements. We present extensive analysis in wavelength range 315-665 nm. method we used was previously described paper I series. cross-dispersion spectrographs determine position centroid spatial profile each spectral order. accuracy 18 mas. At level, are able compare and characterize interest. For better future designs, recommend avoid Zemax model, particular blue spectra, expecting residuals level few tens milli-arcseconds.