Quality Control and
Data Processing

OzPoz table

All raw data (except for BIAS and DARK frames) have two binary tables in addition to HDU#1 hosting the pixels: HDU#2 is the ozpoz table, HDU#3 is the fibre table.

The OzPoz table relates objects on the sky and fibre buttons in Ozpoz. It is partly defined by the user in the Target Setup File. Check out the FPOSS manual for more information.

Column	Content	Comment
Col 1	OBJECT	Identification (from Target Setup File, col 1)
Col 2	RA	Right Ascension (from Target Setup File, col 2)
Col 3	DEC	Declination (from Target Setup File, col 3)
Col 4	R	Button R (polar coordinate) position (microns)
Col 5	R_ERROR	Error in R (microns)
Col 6	THETA	Button Theta position on plate (radians)
Col 7	THETA_ERROR	Error in Theta (radians)
Col 8	TYPE	Object type (M=Medusa science, I=IFU science, S=sky etc.)
Col 9	BUTTON	OzPoz button number
Col 10	PRIO	Object priority (from Target Setup File, col 5)
Col 11	ORIENT	Button orientation
Col 12	IN_TOL	T or F if positioned or not within tolerance (40 microns = 0.08")
Col 13	MAGNITUDE	Target Magnitude (from Target Setup File, col 6; SCIENCE only)
Col 14	V_R	V-R Colour (Science only)
Col 15	COMMENTS	User comments (from Target Setup File, col 8)

The second binary table attached to raw files is the Fibre Table. It relates the fibre buttons on Ozpoz and the fibre positions in the slits, and also includes lab-measured fibre transmission values. This table is static and is maintained by the Observatory.

The columns have the following content:

Column	Content	Comment
Col 1	SLIT	slit name and plate (Medusa1, Medusa2, IFU1, IFU2, Argus)
Col 2	FPS	Progressive position number of fibre in the slit
Col 3	SSN	Subslit number
Col 4	PSSN	Fibre position in the subslit
Col 5	RETRACTOR	Serial number of the retractor
Col 6	BN	Serial number of the button used in the retractor
Col 7	FBN	Serial Number of the Fibre used for the button
Col 8	RP	Retractor position on the plate. This number corresponds to the fibre number used e.g. in FPOSS (target setup file). All even numbers are Medusa fibres.
Cols 9-17	wave	Fibre Transmission values as measured in the lab (as percentage). Each column has a different wavelength.
Col 18	X	X position of the fibre in the reconstructed image matrix
Col 19	Y	Y position of the fibre in the reconstructed image matrix
Col 20	FPD	fibre position on the detector; for Medusa and IFU identical to FPS, for Argus the order is reversed.

The ARGUS image reconstruction using the X and Y columns for the table gives the image in the standard NE orientation on the sky. If the ARGUS position angle was 0 (ARGPOSAN = 0), N is along the X axis and E along the Y axis. The position angle is counted N to E.

Reconstructed ARGUS image.

This table is attached to each pipeline product, as HDU#2. It combines information from the ozpoz and the fibre tables, and includes added information:

Column	Content	taken from	Comment
Col 1	INDEX	pipeline	index of the fibre signal as found by the pipeline
Col 2	FPS	fibre	Progressive position number of fibre in the slit
Col 3	SSN	fibre	Subslit number
Col 4	PSSN	fibre	Fibre position in the subslit
Col 5	RP	fibre	Retractor position on the plate. This number corresponds to the fibre number used e.g. in FPOSS. All even numbers are Medusa fibres.
[Col 6]	[X]	fibre	X position of the fibre in the reconstructed image matrix [IFU and Argus only]
[Col 7]	[Y]	fibre	Y position of the fibre in the reconstructed image matrix [IFU and Argus only]
Col 8	RETRACTOR	fibre	Serial number of the retractor
Col 9	FPD	fibre	fibre position on the detector; for Medusa and IFU identical to FPS, for Argus the order is reversed.
Col 10	OBJECT	ozpoz	Identification (from Target Setup File, col 1)
Col 11	R	ozpoz	Button R (polar coordinate) position (microns)
Col 12	THETA	ozpoz	Button Theta position on plate (radians)
Col 13	ORIENT	ozpoz	Button orientation
Col 14	TYPE	ozpoz	Object Type
Col 15	RA	ozpoz	Right Ascension (from Target Setup File, col 2)
Col 16	DEC	ozpoz	Declination (from Target Setup File, col 3)
Col 17	MAGNITUDE	ozpoz	Target Magnitude (from Target Setup File, col 6; SCIENCE only)
Col 18	TRANSMISSION	...	Applied relative fibre transmission (if corrected for) (SCIENCE only)
Col 19	WLRES	pipeline	OBJECT,SimCal data only: differential wavelength shifts, applied for differential correction and obtained by the pipeline from the SimCal fibres
Col 20	GCORR	pipeline	OBJECT,SimCal data only: geocentric correction to be applied (in km/s)
Col 21	HCORR	pipeline	like above, heliocentric correction
Col 22	BCORR	pipeline	like above, barycentric correction

The INDEX counts the pipeline-detected fibres. It will always increment by one. The FPS represents the physical index of the fibres. As long as it increments along with INDEX, this means that all fibres (up to the present INDEX have been allocated and extracted. An increment by more than 1 means that at least one fibre has given no signal, either because it could not be allocated (fibre broken), or has not been allocated by the user, or had a signal too low for the pipeline to detect. The last possibility will actually not happen since fibre signal localization is always done on flat field data, and if there a fibre gives too low a signal, it can be considered as not operational.

The number of columns in the product files corresponds to the maximum INDEX. There are no columns for fibres with no signal.

Here is an example how the indexing works:

INDEX	FPS	Comment
1	1
2	2
3	3
4	5	fibre FPS 4 has not been allocated
5	6
6	7
7	10	fibre FPS 8 and 9 have not been allocated
8	11
etc.	etc.