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We present an improved characterization of the so-called " long vs. short " anomaly, a non-linear behavior of the WFPC2 chips which results in a decrease of the measured count rate with decreasing exposure time. We demonstrate that: 1) this non-linearity depends strictly on total counts in a stellar image, and is independent of exposure time; 2) the effect(More)
We present a set of tasks developed to process dithered undersampled images. These procedures allow one to easily determine the offsets between images and then combine the images using Variable-Pixel Linear Reconstruction, otherwise know as " drizzle ". This algorithm, originally developed for the combination of the images in the Hubble Deep Field(Williams(More)
A moon or natural satellite is a celestial body that orbits a planetary body such as a planet, dwarf planet, or an asteroid. Scientists seek understanding the origin and evolution of our solar system by studying moons of these bodies. Additionally, searches for satellites of planetary bodies can be important to protect the safety of a spacecraft as it(More)
We provide some background on pointing ACS, and present the dither and mosaic patterns that will be provided as a convenience for HST Cycle 11 Phase II proposal writers. This report supersedes any previous documents which describe specific ACS dither and mosaic patterns-namely, ACS Instrument Science Report 98-02 by Stiavelli, and the engineering versions(More)
(a) B-band (F435W) mosaic of M51 Abstract In January 2005, the Hubble Heritage Team obtained a large 4-color (B, V, I, and Hα) mosaic image of the Whirlpool Galaxy NGC 5194 (M51), and its companion NGC 5195, with the Advanced Camera for Surveys (ACS) onboard the Hubble Space Telescope (HST). The resulting color composite image was released to the community(More)