UNIVERSITY OF CALIFORNIA OBSERVATORIES / LICK OBSERVATORY

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.

Filter Towards Telescope Towards 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

Filter	Towards Telescope	Towards 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