The distance to M31 is 2.5 million light-years (0.8 megaparsecs).
The individual images surrounding the variable star are 5 arcseconds (62.5 light-years or 19.2 parsecs) wide.
The Hubble Space Telescope observations of Hubble's Variable M31-V1 were made possible from ground-based data provided by the American Association of Variable Star Observers (AAVSO).
The image was created from Hubble data from proposal 12326: K. Noll (PI), Z. Levay, M. Mutchler, T. Borders, L. Frattare, M. Livio, C. Christian, H. Bond, and D. Soderblom (Hubble Heritage Team/STScI).
F475X (Wide Blue) and F600LP (Long Pass)
December 2010 - January 2011
NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
May 20, 2011
This image is a composite of separate exposures acquired by the WFC3 instrument on HST. Several filters were used to sample broad and narrow wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: