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SARG
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SARG filters are listed in the following Table . In the table is also indicated the different position on the correspondent filter holder. PS= Preslit Slide; FW= Filter Wheel; FF= Flat Field lamp.
|
Pos. |
Name |
Recipe |
Application |
|
PS3 |
ND
0.5 |
NG4 |
Flux
Calib. |
|
PS4 |
ND
2.0 |
NG9
(1.40) |
Flux
Calib. |
|
PS5 |
ND
3.0 |
NG9
(2.12) |
Flux
Calib. |
|
PS6 |
ND
4.0 |
NG9
(2.83) |
Flux
Calib. |
|
FW2 |
BLUE |
BG40
(1.0) |
Stray
light rejection |
|
FW3 |
GREEN |
KG4
(2.0) |
Stray
light rejection |
|
FW4 |
YELLOW |
GG455
(2.0) |
Order
Sorting |
|
FW5 |
RED |
OG570
(1.0) |
Order
Sorting |
|
FF1 |
FF1 |
UG5(1.2)+NG9(0.3) |
Flats
Balance |
|
FF2 |
FF2 |
BG24(1.0)+BG40(1.5)+UG3(1.0) |
Flats
Balance |
|
FF3 |
FF3 |
BG26(3.0) |
Flats
Balance |
All filters do not affect focus since they are in parallel beam. Image maximum shift on the slit when inserting a filter corresponds to about 0.3 arcsec for a thickness of 3 mm. All filters are tilted by 3 degrees to avoid ghosts.
The neutral density filters are placed in the
Preslit slide (5 positions available). Normal operation of SARG is with Preslit
Slide in position PS1. Filter dimensions are f 12.7 ´ 2 mm. Mechanical dimensions of cell is f 20 ´ 14 mm. Cell mounted in wheel at tilts of 3 degree.
The order sorting and background suppression
filters, as well as custom interference filters, are placed in the Filter Wheel
(12 positions reserved). Normal operation of SARG is with Filter Wheel in
position FW1. Filter dimensions are f 12:7 ´ 2 mm. Mechanical dimensions
of cell is f 20 ´ 14 mm. Cell are mounted in the wheel at tilts of 3
degree.
Each Flat Field calibration lamp is equipped with colored
light balance filters in order to reduce range in intensity due to the poor
output of the lamps in the UV. Each lamp, with its color filter, is intended to
be used in a limited wavelength region with one particular cross disperser. The flat balance filters are mounted in front of the
respective lamps
.
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