October 5-9, 2014


O7.7 PPA Stack: User Driven Image Stacking for ODI data and beyond via a Highly Customizable Web Interface

Soichi Hayashi (Indiana University)

Arvind Gopu (Indiana University), Michael Young (Indiana University); Ralf Kotulla (University of Wisconsin, Milwaukee)

Astronomical archives have recently shown a general trend towards serving standard calibrated data products for their observers; however, the process of combining those data products into stacked images remains a manual exercise left to the end-user. The benefits of astronomical image stacking are well established, and dither patterns are recommended for almost all observing targets. Some archives attempt to automatically produce stacked science images but don't provide any user or operator control for custom parameter sets, thus severely limiting the scientific usefulness of those stacks. Astronomers usually end up having to dowload large amounts of calibrated image data, and use locally deployed stacking applications and complex configuration files to produce their own stacks. In this paper, we present PPA Stack, a web based stacking framework within the ODI - Portal, Pipeline, and Archive system. PPA Stack offers a highly customizable web user interface combined with built-in heuristics (based on pointing, filter, and other metadata information) to pre-sort a large number of images into a set of likely stacks while still allowing the user complete control over the set of images and parameters in each stack they would like to generate. The user interface, designed using the AngularJS Javascript library and Twitter Bootstrap, provides different views of the same information, all of which are synchronized in real time following any user parameter entry or selection (without having to refresh the page). A backend consisting of Python scripts optimized for ODI data, wrapped around the SWarp stacking software, handles the execution of user or operator requested stacking workflow jobs on Indiana University's Big Red II supercomputer, and the subsequent ingestion of the combined images back into the PPA archive. PPA Stack is designed to seamlessly enable integration of other stacking applications and libraries in the future, so each user can select the most appropriate option for their science.

Mode of presentation: Oral (need to be confirmed by the SOC)

Applicable ADASS XXIV theme category: Web services and APIs