Quality Control and
Data Processing

The current total number of available fibres is documented here.

The detailed fibre pattern is useful if one needs to identify missing fibres. The following plots shows raw fibre flats displayed such that one can recognize the signal from individual fibres. This is intended to be able to find SKY and SIMCAL fibres on the data, as well as to check for fibres with low or no signal.

Note: The screen shots are not to scale, but compressed strongly in Y direction, in order to enhance the curvature of the spectral format.

Technical remarks: these displays have been created by MIDAS. Use the following batch to construct such a display from an input raw fibre flat frame:

Midas 001> create/display 1 1150,100,0,860
Midas 002> load <input.fits> scale=-2,-50 cuts=0,<high_cut> center=C

Medusa1

a) before 2003-09-25

b) between 2003-09-25 and 2006-05-03:

c) since 2006-05-04:

d) 2011-11-15 until 2011-12-25 (FPS#27 back):

The Medusa1 slit has 137 fibres, five of which are SIMCAL fibres (marked red on the display). They are organized in 13 subgroups, recognized by gaps. The number of fibres per subgroup varies between 13 and 9. The last two fibres (#136 and #137) are outside the CCD, so a Medusa1 raw file records up to 135 fibres.

FPS27 was broken since 2003-09-25, unavailable until 2011-11-15, enabled until 2011-12-25, disabled again afterwards.

FPS49 was not available between 2006-05-04 and 2006-08-10.

FPS81 unavailable since 2012-03-02.

There are no dedicated SKY fibres. Fibre index starts at left. The signal of the SIMCAL fibres can vary strongly.

Medusa2

The Medusa2 slit has the same format as Medusa1. There are 135 fibres.

Until 2006-08-04: all fibres were available.

FPS13: n/a between 2011-04-18 until 2014-11-28

FPS58: n/a between 2006-12-18 and 2010-10-18

FPS109: n/a between 2006-08-04 and now.

IFU1

The IFU1 fibres are displayed here on the same spatial scale as the Medusa fibres. Their diameter is smaller, and the signal on the CCD is more crowded. A total of 320 fibres exists in the slit. They are organized in 15 bundles, each having 20 object fibres and one SKY fibre (coded green). There are also 5 SIMCAL fibres (coded red here).

Two SKY fibre have no signal (#229, #278), fibre #229 since 2008-01. Fibre #192 was unavailable between 2006-10-01 and about 2014-10-01.

Last fibre with complete signal CCD signal is #316.

Some bundles (2, 9, 14) have overall lower sensitivity.

IFU2

The format is the same as for IFU1. In this slit, SKY#278 is present but SKY#192 is not (showing a very low signal not being extracted by the pipeline). As for IFU1, the last fibres are truncated.

Bundle 5 has lower sensitivity. Since October 13, 2004, fibre #303 has no signal.

Argus

The format is similar to the IFUs, with the exception that the fibre index runs right-left, opposite to the other fibre systems. The first three fibres have their signal outside the CCD and are truncated. All other fibres give a signal.