General specifications
Grating equation

sin α + sin β = mλ/d
λ = wavelengthα, β = angle of incident beam, angle of diffracted beamm = order of the observed diffracted beamd = 1/G grating constantGroove density∆ G ≤ 1 x 10

Blaze wavelength

λB ± 5 %Efficiency anomalies

Efficiency anomalies occur at wavelengths, at which a diffracted beam of a higher order is parallel to the surface. For small
angles (γ < 10°), the following equation is valid:-4

λAN = ± qd (1±sin γ/2)
q = 2/(m-2n)n = order of the gratingdiffracted beam
For autocollimation:
λAN = ± qd (Shown in diagram)
Listed λAN values show minima of the efficiency curve. At the anomalies, the efficiency deviates up to 15 % from the values
shown in the diagrams.
Wavefront aberration
measured at 633 nm (for standard
gratings)

UV/VIS = λ/4
NIR
= λ/2
IR
= 3/2λStraylight

Mechanically ruled ≤ 2 x 10
-5Holographically exposed ≤ 5 x 10

CleanlinessTechnologically caused defects in theruled area (small scratches, small
points etc.) are acceptable, as long as
they are within straylight specificationand do not affect the optical propertiesof the grating.

–42

Plane gratings
Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Holographically, replica
3600 l/mm
250 nm
185 nm1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx90 224

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Holographically, replica
2604 l/mm
230 nm154 und 256 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx90 524

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Holographically, replica
2400 l/mm
230 nm166 und 277 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx90 824

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Holographically, replica
2100 l/mm
230 nm
190 und 317 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx91 024

3

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Holographically, replica
1800 l/mm
230 nm222 und 370 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx91 324

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Holographically, replica
1400 l/mm
250 nm
285 und 476nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx91 824

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Holographically, replica
1302 l/mm
230 nm
307 und 512 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx92 324

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
1302 l/mm
300 nm
307 und 512 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx62 424

4

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
1302 l/mm
400 nm
307 und 512 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx62 524

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
1302 l/mm
480 nm
307 und 512 nm
1.
Unpolarized
Autocollimation
UV-VIS – NIR Spectroscopy
263232xx62 724

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
1302 l/mm
550 nm
307 und 512 nm
1.
Unpolarized
Autocollimation
VIS - NIR Spectroscopy
263232xx62 624

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Holographically, replica
1200 l/mm
225 nm
333 und 555 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx92 824

5

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
1200 l/mm
250 nm
333 und 555 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx12 324

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
1200 l/mm
300 nm
333 und 555 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx12 424

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
1200 l/mm
400 nm
333 und 555 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx12 524

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
1200 l/mm
500 nm
333 und 555 nm
1.
Unpolarized
Autocollimation
VIS - NIR Spectroscopy
263232xx12 624

6

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
1200 l/mm
700 nm
555 nm1.
Unpolarized
Autocollimation
VIS – NIR Spectroscopy
263232xx12 924

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
651 l/mm
300 nm
600 und 1000 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx63 224

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
651 l/mm
420 nm
600 und 1000 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx63 324

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
651 l/mm
480 nm
600 und 1000 nm
1.
Unpolarized
Autocollimation
UV-VIS – NIR Spectroscopy
263232xx63 424

7

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
651 l/mm
550 nm
600 und 1000 nm
1.
Unpolarized
Autocollimation
VIS – NIR Spectroscopy
263232xx63 524

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
651 l/mm
750 nm
600 und 1000 nm
1.
Unpolarized
Autocollimation
VIS – NIR Spectroscopy
263232xx63 724

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
651 l/mm
1000 nm
600 und 1000 nm
1.
Unpolarized
Autocollimation
NIR Spectroscopy
263232xx63 924

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
651 l/mm
1440 nm1000 nm1.
Unpolarized
Autocollimation
NIR Spectroscopy
263232xx64 124

8

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
651 l/mm
1750 nm1000 nm1.
Unpolarized
Autocollimation
NIR Spectroscopy
263232xx64 424

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
610,4 l/mm
1000 nm
600 und 1100 nm
1.
Unpolarized
Autocollimation
NIR Spectroscopy
263232xx73 924

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
600 l/mm
300 nm
660 und 1100 nm
1.
Unpolarized
Autocollimation
UV - VIS Spectroscopy
263232xx13 224

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
600 l/mm
400 nm
660 und 1100 nm
1.
Unpolarized
Autocollimation
UV - VIS Spectroscopy
263232xx13 324

9

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
600 l/mm
500 nm
660 und 1100 nm
1.
Unpolarized
Autocollimation
UV – VIS - NIR Spectroscopy
263232xx13 524

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
600 l/mm
1000 nm
660 und 1100 nm
1.
Unpolarized
Autocollimation
VIS - NIR Spectroscopy
263232xx13 924

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
600 l/mm
1150 nm1100 nm1.
Unpolarized
Autocollimation
NIR Spectroscopy
263232xx13 824

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
600 l/mm
1250 nm1100 nm1.
Unpolarized
Autocollimation
NIR Spectroscopy
263232xx14 024

10

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
600 l/mm
1500 nm1100 nm1.
Unpolarized
Autocollimation
NIR Spectroscopy
263232xx14 124

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
325,5 l/mm
300 nm1230 und 2050 nm
1.
Unpolarized
Autocollimation
UV - VIS Spectroscopy
263232xx65 024

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
325,5 l/mm
430 nm1230 und 2050 nm
1.
Unpolarized
Autocollimation
UV – VIS Spectroscopy
263232xx65 224

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
325,5 l/mm
550 nm1230 und 2050 nm
1.
Unpolarized
Autocollimation
VIS - NIR Spectroscopy
263232xx65 124

11

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
325,5 l/mm
2000 nm1230 und 2050 nm
1.
Unpolarized
Autocollimation
NIR IR Spectroscopy
263232xx65 424

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
300 l/mm
500 nm
1330 und 2220 nm
1.
Unpolarized
Autocollimation
UV-VIS-NIR Spectroscopy
263232xx15 124

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
300 l/mm
1300 nm1330 und 2220 nm
1.
Unpolarized
Autocollimation
NIR Spectroscopy
263232xx14 824

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
300 l/mm
2000 nm1330 und 2200 nm
1.
Unpolarized
Autocollimation
NIR-IR- Spectroscopy
263232xx15 424

12

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
300 l/mm
2850 nm2220 nm1.
Unpolarized
Autocollimation
NIR-IR- Spectroscopy
263232xx15 624

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
300 l/mm
3500 nm2200 nm1.
Unpolarized
Autocollimation
NIR IR Spectroscopy
263232xx15 724

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
162,75 l/mm
200 nm2460 und 4100 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx65 824

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
162,75 l/mm
300 nm2460 und 4100 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx65 924

13

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
162,75 l/mm
500 nm2460 und 4100 nm
1.
Unpolarized
Autocollimation
VIS- Spectroscopy
263232xx66 024

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
162,75 l/mm
4000 nm2460 und 4100 nm
1.
Unpolarized
Autocollimation
NIR-IR Spectroscopy
263232xx66 424

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
150 l/mm
500 nm2660 und 4400nm
1.
Unpolarized
Autocollimation
VIS-NIR- Spectroscopy
263232xx16 024

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
150 l/mm
1250 nm2660 und 4400nm
1.
Unpolarized
Autocollimation
NIR Spectroscopy
263232xx16 224

14

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
150 l/mm
4000 nm2660 und 4400 nm
1.
Unpolarized
Autocollimation
IR Spectroscopy
263232xx16 424

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
150 l/mm
6000 nm2660 und 4400 nm
1.
Unpolarized
Autocollimation
IR Spectroscopy
263232xx16 624

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
130,2 l/mm
6,1 µm
3070 und 5100 nm
1.
Unpolarized
Autocollimation
IR- Spectroscopy
263232xx66 624

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
100 l/mm
800 nm
500 und 833 nm
1.
Unpolarized
Autocollimation
UV-VIS Spectroscopy
263232xx73 724

15

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
75 l/mm
8 µm
5300 und 8900 nm
1.
Unpolarized
Autocollimation
IR Spectroscopy
263232xx17 024

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
81,375 l/mm
8 µm
4900 und 8200nm
1.
Unpolarized
Autocollimation
IR Spectroscopy
263232xx67 424

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
75 l/mm
10 µm
5300 und 8900 nm
1.
Unpolarized
Autocollimation
IR Spectroscopy
263232xx17 124

16

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
75 l/mm
12 µm
5300 und 8900 nm
1.
Unpolarized
Autocollimation
IR- Spectroscopy
263232xx17 224

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
54,2 l/mm
13,8 µm
7350 und 12300 nm
1.
Unpolarized
Autocollimation
IR Spectroscopy
263232xx67 724

TypeGroove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
40,7 l/mm
500 nm9800 und 16400 nm
1.
Unpolarized
Autocollimation
VIS-NIR Spectroscopy
263232xx68 224

Type
Groove density
Blaze
Anomalies λ AN
OrderPolarization
Geometry
Typical application
Part number

Mechanically ruled, replica
24,1 l/mm
32,2 µm
16,6 und 27,7 µm
1.
Unpolarized
Autocollimation
IR Spectroscopy
263232xx69 024

17Laser gratings
Typ:
Groove density
Order
Geometry
Typical application
Part number

Typ:Groove density
Order
Geometry
Typical application
Part number

Holographic sinusoidal grating, replica
2400 l/mm
1.
Autocollimation
Laser reflection grating for Littrow
configuration
263232yy50 824

Typ:Groove density
Order
Geometry
Typical application

Holographic sinusoidal grating, replica
1800 l/mm
1.
Autocollimation
Laser reflection grating for Littrow
configuration
263232yy51 324

Typ:Groove density
Order
Geometry
Typical application

Holographic sinusoidal grating, replica
2100 l/mm
1.
Autocollimation
Laser reflection grating for Littrow
configuration 263232yy51 024

Part number

Part number

Holographic sinusoidal grating, replica
1400 l/mm
1.
Autocollimation
Laser reflection grating for Littrow
configuration
263232yy51 824

18

Typ:
Groove density
Order
Geometry
Typical application
Part number

Typ:Groove density
Blaze wavelength
Anomalies λ AN
Order
Geometry
Typical application
Part number

Holographic sinusoidal grating, replica
1200 l/mm
1.
Autocollimation
Laser reflection grating for Littrow
configuration
263232yy52 824

Mechanically ruled, replica
651 l/mm
700 nm
600 and 1000 nm
1.
Autocollimation
Laser reflection grating for Littrow
configuration
263232yy63 624

Typ:Groove density
Blaze wavelength
Anomalies λ AN
Order
Geometry
Typical application
Part number

Mechanically ruled, replica
130,2 l/mm
10200 nm
3070 and 5100 nm
1.
Autocollimation
Laser reflection grating for Littrow
configuration
263232 5966 725

19Spectrometer gratings
Numberofgrooves
mm-1

Spectral
range

Blaze
Wavelength∆λ nm

λ B nmAngle of
Focal lengthIB
incidence IA
α°

mm

mm

Tipping
angle ofdiode arrayκ°

Dispersion-1

Resolution

Spectrum
lengthDimensions

Activearea

Radius of
blank

nm/mm

∆λ nm

mm

mm²

mm

mm

Part number

2400
185-460
225
28
465
388
*
1.1
0.2
∅ 64x12∅50
393.0
2645102950624
1600
240-440
225
10
150.3
150
-13.0
3.7
0.03
5.5
∅ 25x10∅20149.72645102951924
1400
220-530225
25.0
142.8 152.3
-9.8
4.6
1.3
67.3
∅ 25x10∅20149.72645102952024
1300
790-830810
40.4
108.9 110.4
-6.9
6.4
0.1
6.3
∅ 30x8∅24
109.82645102259825
1220
492-542
500
1.1
163
156.5
-19.2
3.9
0.2
12.8
∅ 50x8∅39
163.1
7920081220
519-568
500
2.1
163
156.5
-19.2
3.8
0.2
12.8
∅ 50x8∅39
163.1
7920081220
560-590
500
-3.7
162
139.3
-26.7
3.4
0.7
8.9
∅ 50x8∅39
163.1
7920081220
200-250
250
23.5
165.3
158
-22.7
4.9
0.47
10.3
∅ 50x8∅39
163.1
7920051220
200-250
250
-3.7
162
164.9
-5.3
4.7
0.51
10.8
∅ 50x8∅39
163.1
7920051220
430-450
250
-3.7
162
154
-18.7
4
0.51
5
∅ 50x8∅39
163.1
792005
1200
230-320
225
-17.4
175
174.4
-2.5
3.9
0.6
24.3
∅ 50x10∅45180.32645102953324
1100
200-500
225
-22.5
175
176.7
-22.1
4.1
0.8
93.1
∅ 50x10∅20
193.62645102953124
1000
190-400
225-6.8
188.5 196.5
-11.3
4.9
0.2
45.1
∅ 50x10∅30
193.62645102952424
950
190-370250-9.6
146.4 151.2
-13.5
6.3
0.67
28.6
∅ 32x7∅26150.7792060845
200-415225
15.4
144.7 133.1
8.4
8.5
1.0
25.4
∅41x10∅35
138.1
2645102952924
845
335-695380
19.1
157.5 128.2
-2.6
9.1
2.5
40
∅41x10∅35
138.1
2645102953024
700
1560-1800
1600
41.0
202.5 201.1
-1.6
6.0
3.0
40
∅90x12∅80
181.5
2645102952724
320
200-800
225
10.0
97.6
122.4
-7.9
25.6
2.0
23.4
∅ 30x8∅26
109.82645102952624
320
200-550
225
-3.8
110
108.1
-18.1
28.8
2.0
12.6
∅ 30x8∅26
109.82645102952724
250
375-750250
0116.3 115.7
-4.7
34
1
11.0
∅ 34x7∅28116.3792004200
190-370
225
-5
182
178
3.1
27.7
1
6.5
∅ 64x10∅50180.32654102950324
200
190-510225-4.5
180.5 178.1
-5.5
27.7
1
11.6
∅ 64x10∅50
180.32645102950324
200
510-830225-2.6
180.5 178.1
-5.5
27.6
1
11.6
∅ 64x10∅50
180.32645102950324
Comments:
Apart from the grating with the groove number of 2400 mm –1 all the other gratings are of the flat field type, making them suitable for use with diode array and CCD
detectorsα

LA Entrance slit
β0
LB

CCD

κ

20

Monochromator gratings
Number ofgrooves
mm-1

Spectral
range

Blaze
Wavelength∆λ nm

λ B nm

1900
1500
1400
1400
1400
1200
1200
1000
1000
651
650
600

250-650
330-850
190-740200-750
250-750
190-740
600-1100
190-850
190-1100
190-850
189-500
200-800

300
450
230
230
400
230
800
230
230
230
230
230

Focal length /mm

LA
219,3
219,3
95
150
150
120
219,3
190
190
219,3
218
120

Dispersion -1

Resolution

LB

nm/mm

∆λ/nm
∆λ

200
200
235
150
150
100
200
189,5
191,9
200
200
97,3

2,3
2,9
2,6
4,1
4,1
7,2
3,6
4,6
4,6
6,6
6,6
14,8

1
1
5
5
5
2
1
2
2
2
1
3

Dimensionsmm∅ 64x12∅ 64x1250x60x1050x60x1050x60x10∅ 30x8∅ 64x12∅ 64x8∅ 50x10∅ 64x10∅ 64x10∅ 30x10

Active area

Radius of blank

mm

mm

∅56
∅56
42x46
42x46
42x46
∅24
∅56
∅50
∅40
∅56
∅56
∅24

207.1
206.4
136.4
149.7
149.7
109.8
204.7
192.7
193.6
214.6
214.6
109.8

Part number

2645102258824
2645102257824
2645102950424
2645102950524
2645102259024
2645102951224
2645102256824
2645102950824
2645102951724
2645102951124
2645102951624
2645102951324

Comments:„22“ in the part number means that the grating grooves have a symmetricl profile. The number “29” indicates a grating with an asymmetric groove
profile.
The angle of deflection ∆ = β−α is always 30°. The angle of reflection β is always larger than the angle of incidence α .
The resolution is valid for the image of the slit center, over a wide area of the spectral range the given resolution is better than the minimum value
specified in the table.

α∆Entrance slit
β

LA
LB
Exit slit

21