The Planck team has yet to release its data for regions near the north and south galactic poles
because those sectors are incredibly difficult to analyze.
Using the Sliding Anglo-Australian Telescope on Siding Spring Mountain in Australia, the survey examines objects in two large wedges of sky at the north and south galactic poles
. Scheduled to finish in 2001, it has already measured the distances to 75,000 galaxies.
Galactic noise is greatest when the antenna is pointed towards the galactic center and lowest when the antenna is pointed towards the galactic poles
. The brightness temperature of this noise decreases with rising RF frequency.
Conversely, if you were scanning the skies for bright open clusters, you probably wouldn't spend a lot of time looking in the starless deserts lying near the galactic poles
Szalay of Johns Hopkins University in Baltimore and his collaborators initially determined the positions of galaxies along a long, narrow line of sight -- a pencil beam -- in the direction of the Milky Way's north and south galactic poles
. The pencil-beam survey suggested that over a distance of 7 billion light-years, galaxies appear in clumps spaced about 420 million light-years apart (SN:5/5/90, p.287).
In contrast, galaxies seem most concentrated where stars are thinly spread - in the general region of the galactic poles
. Today this distribution makes sense because we know that star clusters and nebulae are generally concentrated toward the midplane of the Milky Way's disk, while dust in the disk blocks our view of other galaxies.