2014/03/06 by Stefan Schröder, S. E. Schröder, S. Mottola +3 · 1 citation
Physics and Astronomy · #Asteroid #Astro and Planetary Science #Astronomy #Computer science #Field of view #Framing (construction) #Geography #Geology #ICARUS #Optics #Physics #Planetary Science and Exploration #Remote sensing #Spacecraft #Stellar, planetary, and galactic studies #Stray light #astro-ph.EP
paper · pdf · doi:10.1016/j.icarus.2014.02.018
published as Icarus Volume 234, 15 May 2014, Pages 99-108 · 20 pages, 10 figures
openalex publication_date 2014/03/06 · openalex created_date 2016/06/24 · arxiv created 2017/01/31 · arxiv updated 2017/02/01 · openalex updated_date 2026/08/05
The NASA Dawn spacecraft acquired thousands of images of asteroid Vesta during its year-long orbital tour, and is now on its way to asteroid Ceres. A method for calibrating images acquired by the onboard Framing Camera was described by Schröder et al. (2013; Icarus 226, 1304). However, their method is only valid for point sources. In this paper we extend the calibration to images of extended sources like Vesta. For this, we devise a first-order correction for in-field stray light, which is known to plague images taken through the narrow band filters, and revise the flat fields that were acquired in an integrating sphere before launch. We used calibrated images of the Vesta surface to construct simple photometric models for all filters, that allow us to study how the spectrum changes with increasing phase angle (phase reddening). In combination with these models, our calibration method can be used to create near-seamless mosaics that are radiometrically accurate to a few percent. Such mosaics are provided in JVesta, the Vesta version of the JMARS geographic information system.