F25NDQ - FUV-MAMA

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Description

The F25NDQ mode with the FUV-MAMA detector provides broad-band imaging with attenuation factors that vary between 10-1 and 10-4 with respect to the 25MAMA filter. The full field of view is 25 arcsec × 25 arcsec, but the F25NDQ filter is unique in that it is divided into four quadrants, each having a different neutral density factor. Thus, the field of view for each quadrant is 12 arcsec × 12 arcsec. In clockwise order starting from the upper left these are F25NDQ1, F25NDQ2, F25NDQ3, and F25NDQ4, where the number appended to each name is the approximate dex ND factor. The R80 and central pixel flux are unmeasured but assumed to be approximately the same as produced by the F25SRF2 filter. Approximate dimensions of each quadrant and the default target location in each quadrant are given in Table 14.30.

Recommended Uses

This filter is recommended for broad-band imaging of objects that are brighter than the FUV-MAMA BOP limits by factors between 10 and 104.

Special Considerations

If a target violates BOP restrictions in any quadrant of the F25NDQ aperture, the restrictions regarding pointing close to objects violating safety limits discussed in Chapter 7 and STIS ISR 2000-01 apply. This rule renders the F25NDQ4 quadrant rather useless, and the F25NDQ3 quadrant is redundant with the full field F25ND3 aperture. Also the dividing lines between the quadrants are somewhat displaced from the center of the detector and are not quite parallel to the detector edges (see Figure 13.83 for a lamp image taken through this filter), so observers for whom the exact locations of the quadrant boundaries are important should contact the Help Desk.


Table 14.30: NDQ quadrant dimensions and the default locations at which a target is placed in each quadrant

Aperture

Pivot λ (Å)

FWHM (Å)

AB mag zero point

Speak

Bλ

R80 (arcsec)

Flux in central pixel

F25NDQ1

1416.0

384

20.775

8.95e+12

393

0.3

9%

F25NDQ2

1403.9

384

18.580

1.13e+12

394

0.3

9%

F25NDQ3

1407.3

401

15.898

9.68e+10

415

0.3

9%

F25NDQ4

1433.7

391

13.091

7.95e+09

393

0.3

9%



Figure 14.77: Integrated System Throughputs for F25NDQ FUV-MAMA.




Table 14.31: Sensitivities and Throughputs for F25NDQ aperture with FUV-MAMA.


Sensitivities

 

Throughputs (%)

λ

F25NDQ1

F25NDQ2

F25NDQ3

F25NDQ4

 

F25NDQ1

F25NDQ2

F25NDQ3

F25NDQ4

1150

3.97e+11

6.88e+10

5.32e+09

2.05e+08


 

1.49e-02

2.54e-03

2.00e-04

7.71e-06

1200

3.85e+12

6.30e+11

5.34e+10

2.40e+09


 

1.40e-01

2.30e-02

1.95e-03

8.74e-05

1250

6.58e+12

9.94e+12

8.00e+10

4.70e+09


 

2.31e-01

3.49e-02

2.81e-03

1.65e-04

1300

7.76e+12

1.04e+12

8.33e+10

5.91e+09


 

2.58e-01

3.50e-02

2.81e-03

1.99e-04

1350

8.05e+12

1.02e+12

8.54e+10

6.69e+09


 

2.62e-01

3.31e-02

2.78e-03

2.18e-04

1400

7.80e+12

9.76e+11

8.43e+10

6.92e+09


 

2.45e-01

3.06e-02

2.65e-03

2.17e-04

1450

6.97e+12

8.69e+11

7.61e+10

6.36e+09


 

2.11e-01

2.63e-02

2.31e-03

1.93e-04

1500

5.76e+12

7.23e+11

6.38e+10

5.41e+09


 

1.69e-01

2.12e-02

1.87e-03

1.59e-04

1550

4.74e+12

5.95e+11

5.24e+10

4.57e+09


 

1.34e-01

1.69e-02

1.49e-03

1.30e-04

1600

3.83e+12

4.68e+11

4.08e+10

3.70e+09


 

1.05e-01

1.29-02

1.12e-03

1.02e-04

1650

3.15e+12

3.72e+11

3.20e+10

3.02e+09


 

8.40e-02

9.91e-03

8.53e-04

8.05e-05

1700

2.29e+12

2.68e+11

2.28e+10

2.22e+09


 

5.93e-02

6.93e-03

5.90e-04

5.73e-05

1750

1.54e+12

1.86e+11

1.57e+10

1.54e+09


 

3.89e-02

4.66e-03

3.94e-04

3.87e-05

1800

1.03e+12

1.25e+11

1.06e+10

1.03e+09


 

2.50e-02

3.05e-03

2.59e-04

2.52e-05

1850

4.15e+11

4.95e+10

4.28e+09

4.06e+08


 

9.87e-03

1.18e-03

1.02e-04

9.68e-06

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