Dear colleagues, We are very happy to announce the v4.3 release of the Astropy package, a core Python package for Astronomy: http://www.astropy.org Astropy is a community-driven Python package intended to contain much of the core functionality and common tools needed for astronomy and astrophysics. It is part of the Astropy Project, which aims to foster an ecosystem of interoperable astronomy packages for Python. New and improved major functionality in this release includes: * Transformations to AltAz are now much more precise (and faster) * Improvements in making Astropy thread-safe * Performance improvements to sigma clipping * Changes in the Time and IERS leap second handling * Support for multidimensional and object columns in ECSV * Support for reading and writing tables to QDP format * Append table to existing FITS file * General masked class for Quantity and other ndarray subclasses * Configuration file improvements * Support for different solvers and bracket option in z_at_value In addition, hundreds of smaller improvements and fixes have been made. An overview of the changes is provided at: http://docs.astropy.org/en/stable/whatsnew/4.3.html Instructions for installing Astropy are provided on our website, and extensive documentation can be found at: http://docs.astropy.org If you usually use pip/vanilla Python, you can do: pip install astropy --upgrade Note that this will yield astropy v4.3.1 instead of 4.3, which is expected - a significant bug reported between the 4.3 release and this announcement means that the correct version is indeed 4.3.1. If you make use of the Anaconda Python Distribution, soon you will be able update to Astropy v4.3.1 with: conda update astropy Or if you cannot wait for Anaconda to update their default version, you can use the conda-forge channel: conda update -c conda-forge astropy Please report any issues, or request new features via our GitHub repository: https://github.com/astropy/astropy/issues Over 400 people have contributed code to Astropy so far, and you can find out more about the team behind Astropy here: https://www.astropy.org/team.html The LTS (Long Term Support) version of Astropy at the time of v4.3's release is v4.0 - this version will be maintained until the next LTS release (v5.0, scheduled for Fall 2021). v4.0.6 is the latest version, also just released. Additionally, note that the Astropy 4.x series only supports Python 3. Python 2 users can continue to use the 2.x series but it is no longer supported (as Python 2 itself is no longer supported). For assistance converting Python 2 code to Python 3, see the Python 3 for scientists conversion guide. If you use Astropy directly for your work, or as a dependency to another package, please remember to acknowledge it by citing the appropriate Astropy paper. For the most up-to-date suggestions, see the acknowledgement page, but as of this release the recommendation is: This research made use of Astropy, a community-developed core Python package for Astronomy (Astropy Collaboration, 2013, 2018). We hope that you enjoy using Astropy as much as we enjoyed developing it! Erik Tollerud v4.3 Release Coordinator on behalf of The Astropy Project https://www.astropy.org/announcements/release-4.3.html