Echelle Line Spread Functions

Spectral Purity, Order Confusion, and Peculiarities

Echelle Line Spread Functions

Table 13.39: Spectral Resolution for Echelle Medium-Resolution Modes (E230M, E140M)

Slit

Spectral Resolution (FWHM in pixels)

Point Source

Extended Source

1200

Å

1500

Å

1700

Å

2400

Å

0.1X0.03

0.9

0.9

1.0 ¹,1.6 ²

1.6

~1

0.2X0.2

1.4

1.3

1.11, 2.02

1.9

~6

0.2X0.06

1.3

1.2

1.1 ¹, 1.8 ²

1.7

~2

6X0.2

1.6

1.4

1.2 ¹, 2 ²

1.9

~6

1 FWHM with FUV-MAMA (E140M).

2 FWHM with NUV-MAMA (E230M).

**Table 13.39: Spectral Resolution for Echelle Medium-Resolution Modes (E230M, E140M)**
Slit	Spectral Resolution (FWHM in pixels)
Point Source	Extended Source
1200 Å	1500 Å	1700 Å	2400 Å
0.1X0.03	0.9	0.9	1.0 ¹,1.6 ²	1.6	~1
0.2X0.2	1.4	1.3	1.11, 2.02	1.9	~6
0.2X0.06	1.3	1.2	1.1 ¹, 1.8 ²	1.7	~2
6X0.2	1.6	1.4	1.2 ¹, 2 ²	1.9	~6

Figure 13.88: Echelle Line Spread Functions, E140M (top) and E230M (bottom)

Table 13.40: Spectral Resolution for Echelle High Resolution Modes (E140H, E230H)

Slit

1200

1500

1700

2400

Extended Source

0.1X0.03

0.8

0.8

1 ¹, 1.5 ²

1.5

~1

0.2X0.2

1.3

1.1

11, 1.82

1.7

~6

0.2X0.09

1.2

1.1

1 ¹, 1.7 ²

1.7

~2

6X0.2

1.4

1.2

1.2 ¹, 2 ²

1.8

~5

1 FWHM with FUV-MAMA (E140M).

2 FWHM with NUV-MAMA (E230M).

**Table 13.40: Spectral Resolution for Echelle High Resolution Modes (E140H, E230H)**
Slit	1200	1500	1700	2400	Extended Source
0.1X0.03	0.8	0.8	1 ¹, 1.5 ²	1.5	~1
0.2X0.2	1.3	1.1	11, 1.82	1.7	~6
0.2X0.09	1.2	1.1	1 ¹, 1.7 ²	1.7	~2
6X0.2	1.4	1.2	1.2 ¹, 2 ²	1.8	~5

Figure 13.89: Echelle Line Spread Functions, E140H (top) and E230H (bottom)

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