Posted by Richard Miles at 16:42 on 2014 Jan 04
Thanks for this Graham.I must mention that back in 2012 October, Jean Meeus added the following comment to an e-mail note about the opposition brightnesses of Ceres and Vesta:"There is something else that is interesting about Ceres and Vesta.In April 2014, these two asteroids will reach opposition with theSun at a time inteval of less than 48 hours. During almost eightmonths they will stay less than 5 degrees from each other in thesky, and during almost two months at less than 2 degrees.On 2014 July 5 their angular separation will be only 10 arcminutes,their least angular distance since at least the year 1800."Jean MeeusSince we know that Vesta changes colour slightly as it rotates, whereas Ceres does not, it would be useful to verify whether these changes can be detected photometrically. Maybe the easiest way of doing this is to do a time-series of images using a DSLR camera with enough FOV that both objects are on the same frame and then to extract the Red, Green and Blue FITS files and measure the relative B-V, V-R and B-R magnitude of Vesta relative to Ceres vs. time. Vesta rotates in just 5.34 hours so a 6-hr run should follow more than an entire rotation.