Astronomical data are getting bigger and bigger. They’re so big now that it’s completely impractical for researchers to obtain local copies of many important datasets, pushing us into the the age of “science platforms”: instead of running analysis software on local hardware, researchers do their work by interfacing with powerful remote systems. This paradigm shift creates both new opportunities and new challenges. A major challenge has to do with data visualization: existing astronomy data visualization tools are often desktop applications designed for local datasets that are small, in the sense that they must fit in a single computer’s memory. In the age of the science platform, visualization applications need to handle huge datasets, and they need to provide a seamless user experience when such datasets live on remote servers. Fortunately, we have a great software platform for building such applications: the web browser. Modern browsers are tools that power complex, interactive, network-native, multimedia applications, thanks to billions of dollars of industry investment. Indeed, the rise of the science platform is closely tied to the development of JupyterLab, a web-native framework for interactive computing. This tutorial will introduce participants to the tools and concepts that underpin modern, browser-based interactive astronomical visualization software, including aspects relating to the visualization user experience (UX) design. It will do so while working through the steps to visualize very large (gigapixel and beyond) FITS imagery interactively in JupyterLab using new features introduced in the “2022 edition” of AAS WorldWide Telescope (WWT) and its related tooling.

In the Jupyter ecosystem, data visualization is usually done with “widgets” created as notebook cell outputs. While this mechanism works well in some circumstances, it is not well-suited to presenting “ds9-like” interfaces that are long-lived, interactive, and visually rich. Unlike the traditional Jupyter notebook system, the newer JupyterLab application provides a sophisticated extension infrastructure that raises new design possibilities. Here we present a novel user experience (UX) for interactive data visualization in JupyterLab that is based on an “app” that runs alongside the user's notebooks, rather than widgets that are bound inside them. We have implemented this UX for the AAS WorldWide Telescope (WWT) visualization tool and will demonstrate it in operation. JupyterLab's messaging APIs allow the app to smoothly exchange data with multiple computational kernels, allowing users to accomplish tasks that are not possible using the widget framework. While we have developed this UX for WWT, the overall design is portable to other applications and has the potential to unlock a variety of new user activities that aren't currently possible in “science platform” interfaces.