Broad band filters

 

Filter

central wave

FWHM

Cut on 5%

Cut on 50%

Cut off 50%

Cut off 5%

Status

Blocking

z

0.903

0.163

0.825

0.827

 0.990

 0.998

in

yes

Y

1.034

0.075

0.988

0.997

1.070

1.079

in

yes

J

1.209

0.247

1.078

1.085

 1.333

1.344

in

yes

Js

1.242

0.163

1.150

 1.161

 1.323

1.334

 

yes

J_low

1.198

0.095

1.141

1.151

1.245

1.254

 

no

J_high

1.302

0.106

1.239

1.249

1.355

1.364

 

no

H

1.648

0.267

1.502

1.515

 1.780

 1.797

in

yes

K'

2.105

0.350

1.905

1.930

 2.277

 2.294

in

no

Ks

2.151

0.304

1.974

2.001

 2.302

 2.313

in

no

K

2.208

0.384

1.977

2.005

 2.387

 2.400

in

no

Methane off

1.579

0.101

1.510

1.531

1.629

1.639

in

yes

Methane on

1.692

0.102

1.621

1.642

1.741

1.752

in

yes

blocking zJ

 

 

 

 

 

 

in

 

blocking HK

 

 

 

 

 

 

in

 

 

 Narrow band filters

 

Filter

central wave

width

Status

Blocking

He I

1.083

1%

 

tbd

Pa g

1.093

1%

 

tbd

continuum

1.206

1%

 

yes

O I

1.238

1%

 

tbd

Fe II

1.256

1%

 

tbd

Pa b

1.281

1%

in

tbd

Fe II

1.644

1%

in

tbd

continuum

1.709

1%

 

no

He I

2.062

1%

in

tbd

H2

2.122

1%

in

no

continuum

2.144

1%

in 

yes

Br g

2.166

1%

in

no

H2

2.249

1%

 

tbd

continuum

2.260

1%

 

tbd

CO

2.295

1%

 

yes

 

All wavelengths are in microns

 

Some filter need an appropriate blocking filter to suppress radiation beyond 2.6 microns. The use of these is coded in the wheel macros by Calar Alto staff and the user need not take care of this if he uses the wheel macros to position the filter wheels.