2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/9068The Sloan Digital Sky Survey has already doubled the number of spectroscopically identified white dwarfs. However, there remains a wealth of white dwarfs in the McCook & Sion catalog for which little or nothing is known. We have thus undertaken a spectroscopic survey of all Northern hemisphere DA white dwarfs from this catalog in order to (1) confirm the spectroscopic classification, and (2) provide measurements of Teff and log g for each star. As part of this project, we have also secured spectroscopic data for all DA stars with high-speed photometric measurements available, in order to study the purity of the ZZ Ceti instability strip, which has recently been challenged, once again.4 pages, 3 figures, 14th European Workshop on White Dwarfs, ASP Conference Series, in pressAstrophysicstext