SWEEPS ACS/WFC Color Composite

Color composite of ACS/WFC images (V and I band filters) showing one-half of the Hubble Space Telescope field of view in the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS). The stars in the Galactic disk and bulge have a mixture of colors and masses. The field is so crowded with stars because Hubble was looking across 26,000 light-years of space in the direction of the center of our galaxy.

Half of these stars are bright enough for Hubble to monitor for any small, brief and periodic dips in brightness caused by the passage of an exoplanet passing in front of the star, an event called a transit. Hubble took approximately 520 pictures of this field, at red and blue wavelengths, from Feb. 22-29, 2004.

About the colours

This image is a composite of many separate exposures made by the ACS instrument on the Hubble Space Telescope using two different filters. Two filters were used to sample broad wavelength ranges. The color results from assigning different hues (colors) to each monochromatic image. In this case, the assigned colors are: Blue: F606W (V) Green: F606W (V) + F814W (I) Red: F814W (I)

About the data

This image was created from HST data from proposal 9750 : K. Sahu, and H. Bond (STScI), T. Brown (High Altitude Observatory, Boulder), S. Casertano and M. Livio (STScI), D. Minniti (Catholic University of Chile), N. Panagia (STScI), A. Renzini (Astronomical Observatory of Padova, Italy), R. Rich (University of California, Los Angeles), and M. Zoccali (Catholic University of Chile). The science team also includes J. Valenti, E. Smith, T. Brown, W. Clarkson, and S. Lubow (STScI), and N. Piskunov (Uppsala University, Sweden).