  Sun-as-a-star observations are very important for the study of the conditions
within the Sun and in particular for the deep interior where higher degree
modes do not penetrate. They are also of significance in this era of dramatic
advances in stellar asteroseismology as they are comparable to those measured
in other stars by asteroseismic missions such as CoRoT, Kepler, and MOST. More
than 17 years of continuous measurements of SoHO and more than 30 years of
BiSON observations provide very long data sets of uninterrupted helioseismic
observations. In this work, we discuss the present status of all these
facilities that continue to provide state- of-the-art measurements and
invaluable data to improve our knowledge of the deepest layers of the Sun and
its structural changes during the activity cycle.

Solar and Stellar Astrophysics