Smoothing the Velocity Axis

The task hanning allows you to Hanning smooth the velocity of a cube (regardless of which axis it is) and write out the smoothed data set. Any blanked pixels are treated as zeros.

HANNING
in=ngc253.icln	Input cube
region	Unset for full cube
out=ngc253.icln-hann	Output image
width=3	Standard Hanning smooth

Having produced the smoothed cube, you could then drop every other channel (as they are no longer independent) with imsub. In the example, we assume the velocity axis is the third axis.

IMSUB
in=ngc253.icln-hann	Input cube
out=ngc253.icln-hann-ind	Output image
region	Unset for full cube
incr=1,1,2	Pick out every other pixel on third axis