The initial images of the far side were limited to a region of the Sun within a heliocentric angle less than about 50 degrees from the antipode of disk center. In 2001, Braun and Lindsey demonstrated in this ApJ Letter how holographic procedures may be employed to produce diffraction limited images of the entire far surface (and poles) of the Sun as shown in the Figure to the left. The top four panels show composite images of the near-side magnetic flux density and far-side acoustic travel-time perturbations for four succesive days, and the bottom panel shows a synoptic magnetogram for the following solar rotation. Here is a nice mpeg, courtesy of Phil Scherrer, showing a sequence which compares full-hemisphere MDI farside images with the previous images.
During 2001, the newly upgraded GONG+ network began returning high resolution images. Using some of the first 24 hours of continuous data available, a comparison of far side images made from GONG+ and MDI was made (see figure to the right). The images are nearly identical, demonstrating the feasibility of continuous montioring of the solar far side using the GONG+ network. See the GONG farside imaging site for the daily image from GONG, as well as more information.
Below are links to some of the press releases and media coverage of far-side imaging as well as graphics and movies prepared for public dissemination. Note that most of the outdated links to the media coverage were removed.
Links to far-side imaging services and related items:
SOI-MDI far-side synoptic maps
spaceweather.com (now includes daily far-side image)
GONG farside imaging site
SWAN far side site (another interesting way to monitor the solar far side)
Links to press releases and media coverage:
Press release on first far-side image from GONG+
ESA release on initiation of routine far-side service
NASA's Space Science Update: press releases and graphics
SOHO Hot Shot
National Science Foundation's press release
MDI-SOI site at Stanford with links to more movies and media coverage
This research uses solar observations obtained primarily from the Solar Oscillations Investigations - Michelson Doppler Imager on SOHO and the Global Oscillations Network Group (GONG), and is funded by the National Science Foundation and the National Aeronautics and Space Administration.