= Infrared photometric band
The traditional near- and thermal-infrared photometric bands in the 1–5 micrometre region are $J,H,K,L,M$, with approximate centers $1.25,1.65,2.2,3.5,4.8$ micrometres. Variants such as $K_s$, $L'$ and $M'$ have different detailed responses. They largely follow <atmospheric windows>; transmission, <sky brightness>, and detector response determine practical band edges. The https://www.eso.org/instruments/isaac/doc/VLT-MAN-ESO-14100-0841_v76.pdf[ISAAC filter documentation] records instrument-specific variants, including an $L$ filter closer to $L'$ near 3.8 micrometres.
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