By Gael Mariani
The paper "Modern observations of Hubble's first-discovered Cepheid in M31" has been accepted for publication to PASP, and is now available on arXiv.org.
RS Puppis as imaged with the ESO NTT (from Kervella et al. 2008)
July 16, 2010: An observing campaign is being carried out on M31_V1, the first variable star discovered in M31 by Edwin Hubble. The Hubble Heritage Team, with Dr. Keith Noll, Space Telescope Science Institute (STScI), as Principal Investigator, plans to observe M31_V1 with the Hubble Space Telescope (HST), and needs to know the phase of this Cepheid variable. Although basic parameters are known for this star, no recent photometry exists, so observations are required to generate current phase information.
Distances in the universe are so vast that we do not have a simple way of measuring them. For distances within the solar system we can measure them directly, using radar for example, and some very straightforward trigonometry. But radar is hard to use when it takes light minutes or hours to cross the solar system; and the nearest star is four light years awa