The Galactic center (l = 0°) is on the right, Cygnus (l=90°) on the left.
Flashing on and off is a false-color map of CO velocity-integrated intensity,
which is proportional to molecular gas column density.
The intense (red-to-white) horizontal lane of CO emission is produced
by inner-Galaxy clouds which are too distant to be seen as dark nebulae.
The optical image is from a panorama produced by A.Mellinger.