Hubble ACS Visible Image of M51
M51, Whirlpool Galaxy
About 31 million light-years (9.6 million parsecs)
This image is 3 arcminutes (20,000 light-years or 6,000 parsecs) wide.
The Hubble image was created from HST data from proposal 10452: S. Beckwith (STScI), R. Kennicutt Jr. (University of Arizona), and H. Bond, C. Christian, L. Frattare, F. Hamilton, Z. Levay, M. Mutchler, K. Noll, and T. Royle (The Hubble Heritage Team, STScI).
Note: High level science products (combined and mosaiced fits files for each filter) are available at: http://archive.stsci.edu/prepds/m51/
F435W (B), F555W (V), F658N (Halpha + [N II]), F814W (I)
This image is a composite of many separate exposures made by the ACS instrument on the Hubble Space Telescope. The color results from assigning different hues (colors) to each monochromatic image. In this case, the assigned colors are:
Blue: F435W (B)
Green: F555W (V)
Red: F658N (Halpha + [N II]) + F814W (I)