Spectrograph CCD images should be oriented consistently

[chazshapiro]

Blue edge on LEFT

Same slice on top (L?)

[astronomerdave]

which edge is blue and how do I know which slices are the same?

[chazshapiro]

BIASSEC, CCDSEC, DATASEC also need to be correct in all orientations

[chazshapiro]

I'm showing I-channel in red, R-channel in blue.

For Fe-Ar lamp, I is a bit emptier on the red side and R is a bit emptier on the blue side:

For now, until Matt fixes it, there is "shmutz" between the spatial slices. Some of the shmutz is closer to one slice than to the center slit -- call that SLICE A:

This orientation and headers need to be consistent for all CCD amp modes.

[chazshapiro]

So either R or I needs to be flipped vertically to get the slices in the same order.