Institution(s): 1. University of Colorado
Advanced Spectral Library (ASTRAL) is a Hubble Large Treasury Project, whose aim is to collect high-quality ultraviolet (1150–3100 Å) spectra of bright stars, utilizing the echelle modes of powerful Space Telescope Imaging Spectrograph; with resolution and signal-to-noise rivaling the best that can be achieved at ground-based observatories in the visible. During HST Cycle 18 (2010–2011), ASTRAL was allocated 146 orbits to record eight representative late-type ("cool") stars, including well-known cosmic denizens like Procyon and Betelgeuse. In Cycle 21 (2013–2014), ASTRAL was awarded an additional 230 orbits to extend the project to the hot side of the H-R diagram: 21 targets covering the O–A spectral types, including household favorites Vega and Sirius. The second part of the program was completed in January 2015. I describe the scientific motivations for observing hot and cool stars in the UV; the unique instrumental characteristics of STIS that enabled a broad survey like ASTRAL; progress in the program to date; and prospects for the future.