by NoelC » Fri Nov 16, 2007 2:31 pm
The image is actually from fairly old exposures.
The Palomar folks did a very high quality survey of the sky several decades ago, through blue, red, and infrared filters, onto photographic plates. This is called the POSS2 survey. Since then, the Space Telescope Science Institute has scanned these plates and made the data available online. This highly accurate data forms, among other things, the basis of the database used to aim the Hubble Space Telescope.
It's also, with suitable processing, a great source of beautiful deep sky imagery.
There was some light pollution in the exposures, in addition to some satellite trails, all of which I removed digitally when preparing this image.
-Noel
The image is actually from fairly old exposures.
The Palomar folks did a very high quality survey of the sky several decades ago, through blue, red, and infrared filters, onto photographic plates. This is called the POSS2 survey. Since then, the Space Telescope Science Institute has scanned these plates and made the data available online. This highly accurate data forms, among other things, the basis of the database used to aim the Hubble Space Telescope.
It's also, with suitable processing, a great source of beautiful deep sky imagery.
There was some light pollution in the exposures, in addition to some satellite trails, all of which I removed digitally when preparing this image.
-Noel