We study visible and infrared spectra, from 310 nm to 5 microns, obtained during the 21st August 2017 eclipse. The instruments were situated at Camp Wyoba (altitude 2402 m) on Casper Mountain, WY.

A short guide to spectroscopy is given, with emphasis upon the elementary physics needed to understand and begin modeling the radiation emerging from astrophysical plasmas using the Sun as a guide, without bias towards a particular region of the Sun's atmosphere.

Jenna Samra and Philip Judge identify two new emission features observed during the 21st August 2017 total solar eclipse by a novel spectrometer, AIR-Spec, flown at 14.3 km altitude aboard the NCAR Gulfstream V aircraft.

Language Summary or Abstract: We present a fast multi-level and multi-atom non-LTE radiative transfer method for dynamically evolving stratified atmospheres, such as the solar atmosphere. The preconditioning method of Rybicki & Hummer (RH92) is adopted.

We study broad red-shifted emission in chromospheric and transition region lines that appears to correspond to a form of post-flare coronal rain.

The variation of the vector magnetic field along structures in the solar corona remains unmeasured. 

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.

We consider the observational basis for the belief that flare ribbons in the chromosphere result from energy transport from the overlying corona. We study ribbons of modest flares using magnetic as well as intensity data from the Hinode, SDO and IRIS missions.

We study UV spectra obtained with the SO82-B slit spectrograph on board SKYLAB to estimate the fine structure splitting of the Cl-like 3p43d4D5/2 and 3p43d4D7/2 levels of Fe X.