The standard U (ultraviolet), B (blue), and V (violet) transmittance curves are shown in the graph above. The peak
responses for the suite of standard astronomical filters are given in the following table. The first ones defined were
U, B, V, R (red), and I (infrared). Far-infrared filters were then named by using the letters following I.
| filter |
response |
| U |
360 nm |
| B |
440 nm |
| V |
550 nm |
| R |
700 nm |
| I |
900 nm |
| J |
1.25  m |
| K |
2.2 m |
| L |
3.4 m |
| M |
5.0 m |
| N |
10.2 m |
| Q |
21 m |
