SDSS Image of 3c273 with standard log scaling. SDSS Image of
3C273 with new LogLog scaling. If you compare an SDSS image
versus one for another optical survey like the DSS, there
usually appears to be a lot less there. However this is mostly
an artifact of the scaling of images. The SDSS images are
derived from CCDs rather than photographic plates. You can get
something much closer to the plate images if you do a
log(log(b)) scaling of the image. Our test version of SkyView
now has a loglog scaling option. We first multiply the each
pixel so that that smallest positive value has the value 1.01.
Then we take the log of each pixel in that image, Finally we
take the log of that result. The ImageJ log function that we use
returns a value of 0 for inputs of 0 or less, so those values
all end up at 0. If you want to really bring out detail in the
image you’ll soon be able to try scaling=loglog. The two images
that start the post show the difference between Log and LogLog
scaling. In the loglog image, the jet is pla