ISON last night
C/2012 S1 ISON @ 2013-11-20
GSO 8" f/4 Refractor + Canon EOS 350D camera (15×25 sec. at ISO 800)
November 20 was the last night to see the comet before dawn in its way to perihelion. At 5 magnitude, to the limit for see it at naked eye. Although not fit in the 1,5º field of image, it shows a long bluish gas tail, inside seems have a narrow
orange band caused by sodium emission that only occurs near the Sun.
José J. Chambó