  Observational solar physics is entering a new era with the advent of new 1.5
m class telescopes with adaptive optics, as well as the Daniel K. Inouye 4 m
telescope which will become operational in 2019. Major outstanding problems in
solar physics all relate to the solar magnetic field. Spectropolarimetry offers
the best, and sometimes only, method for accurate measurements of the magnetic
field. In this paper we highlight how certain atomic transitions can help us
provide both calibration data, as well as diagnostic information on solar
magnetic fields, in the presence of residual image distortions through the
atmosphere close to, but not at the diffraction limits of large and polarizing
telescopes. Particularly useful are spectral lines of neutrals and singly
charged ions of iron and other complex atoms. As a proof-of-concept, we explore
atomic transitions that might be used to study magnetic fields without the need
for an explicit calibration sequence, offering practical solutions to the
difficult challenges of calibrating the next generation of solar
spectropolarimetric telescopes. Suggestions for additional work on atomic
theory and measurements, particularly at infrared wavelengths, are given. There
is some promise for continued symbiotic advances between solar physics and
atomic physics.
