Observing Bundles

The SP has six focal stations for science bundles (see Figure 4). However, only three bundles are mounted in the standard configuration. The different SP positions are described in Table 1.

 

code bundle Calibration/Observation SP position

01 void OBS 5

02 void CAL 6

03 sb2 OBS 4

04 void CAL 5

05 sb1 OBS 3

06 sb2 CAL 4

07 sb3 OBS 2

08 sb1 CAL 3

09 void OBS 1

10 sb3 CAL 2

11 void OBS 6

12 void CAL 1

13 ACQ OBS

These bundles were manufactured by the IAC, using Ceramoptec fibres. The bundles sb1 and sb2 use `ultradry special' hydrogen treated fibres. Bundle sb3 uses Optram `UV' fibres. Each is 5.5m long. Their spectral response can be found in figures 7 and 8.

 
Figure 7: Transmission of the fibers (5.5m) used for sb1 and sb2, according to the fiber manufacturer

 
Figure 8: Transmission of the fibers (5.5m) used for sb3, according to the fiber manufacturer

At the focal plane the fibres are arranged in two groups, one forming a rectangle, and the other a ring which is intended for collecting background light (for small-sized objects). Table 2 and Figure 9 show the main characteristics of each bundle.

 

Bundle 1 2 3 4 5 6

sb1 0.45 0.7 205 (175+30) 7.80$$6.40 variable 90

sb2 0.90 1.4 219 (189+30) 16.0$$12.3 4.6 90

sb3 2.70 4.0 135 (115+20) 33.6$$29.4 7.4 90 1 - fibre core diameter (arcsec) 2 - fibre image size on the detector (to be convolved with a 1.4-2.6 pixel PSF) 3 - total number of fibres (rectangle + ring) 4 - spatial coverage of the central rectangle (arcsec $$ arcsec) 5 - distance between adjacent fibre/spectra at the CCD (in pixels) 6 - diameter of the outer ring (arcsec)

For each bundle the fibre correspondence between the focal plane and slit position is given in Appendix 1.

 
Figure 9: Configuration of the fibres of the standard bundles, at the focal plane end.