IRCAL Filter Characteristics

IRCAL Filter Visible-Light Colors

This document described the appearance of the various IRCAL filters to the human eye, and is intended as an aid in not getting things confused when swapping them out. Compiled from notes by Jamie Lloyd and Marshall Perrin

Note that the labelling of filter sides as "Towards Telescope" and "Towards Detector" is arbitrary and merely reflects how they are currently installed. Filters will work properly in either direction.

FilterTowards TelescopeTowards Detector
J green gold pale pink with hint of green
H ? gold/lime
Ks ? magenta
K emerald ?
BrG ? blue-green
H2-2.12 ? green-blue
KCont bright green pale green
CH4_K purple, 3/4" silver green 1/2"
2.2/0.04 slate gray purple-brown
FeII straw yellow emerald
CH4_J transparent! blue-ish transparent! blue-ish
ND2 dark gray dark gray

Elinor Gates
Last modified: Wed Jun 4 11:01:59 PDT 2003