  In ground based astronomical observations, atmospheric dispersion shifts the
image of the object at different wavelengths due to the wavelength-dependent
index of refraction of the atmosphere. Thus, using an Atmospheric Dispersion
Corrector (ADC) is mandatory in order to avoid any wavelength dependent losses.
Typical ADC configurations, for high resolution astronomical instruments, are
two counter-rotating prisms, a set of, at least, four prisms paired together.
With the arrival of large telescopes with higher angular magnification, and
spectrographs with higher resolution, the requirements on the dispersion
correction are becoming more critical due to the impact on the produced science
(e.g. radial velocity precision). We developed an ADC optical design tool in
order to select the best set of glasses in terms of residuals, transmission,
resulting image quality, Fresnel losses, taking into account the required
spectral range and typical atmospheric conditions where the ADC will be
working. A demonstration of the capabilities of the tool is presented with the
analysis of the impact of different melt data, the effect of different glass
Sellmeier coefficients between catalog and measured ones, that can create a
difference in the residuals above few tens of milli-arcseconds (mas). The tool
allows the investigation of critical steps on the ADC design phase and speeds
up the glass selection process critical for the harder requirements of the
future instruments/telescopes.
