This special issue of Astronomy & Astrophysics
contains a series of scientific articles, which are based on data
obtained with the GREGOR solar telescope in 2014 and 2015. This period
represents the initial phase of scientific use, and was carried out
jointly by all partners of the GREGOR consortium. These articles
demonstrate the potential of the telescope and its instruments at this
early stage of development.
Astronomy & Astrophysics is publishing a special issue
of 28 articles to describe the latest release of data gathered by the
European Space Agency's Planck satellite, which took place between
February and August 2015. This series of papers presents the data
products released and the scientific results extracted from them by the
Planck Collaboration.