filtercode	a0	 a1	  a2	   a3
g		+0.00128 -0.10699 +0.00392 +0.00152
r		-0.00518 -0.03561 +0.02359 -0.00447
i 		+0.00585 -0.01287 +0.00707 -0.00178
z		+0.00144 +0.07379 -0.03366 +0.00765