Difference: AAOmegaFileFormat (4 vs. 5)

Revision 52007-04-22 - RonHeald

Line: 1 to 1
	AAOmega File Format (or, which spectrum is which object?)
Line: 29 to 29
	An Important Note on 2dF Fibre-Pivot Number and 2dfdr Fibre Number
Changed:
< <	There are two very important, and very different, numbers which one must understand in order to recover the information on which object each fibres was allocated to. Fibre slit position AND 2dF Fibre-Pivot position. For the most part there is a one-to-one correspondence between these number. Usually the fibre at AAOmega slit position 1 (bottom of the CCD image) will map directly to 2dF Pivot position 1, and 400 will map to 400 (note, 400 is a guide fibre and so maps to a blank space at the top of the CCD image). However, during manufacture or repair of each of the AAOmega slit units, it is some times possible for the order of fibres in each of the AAOmega slits to fall out of synchronization with the 2dF Pivot numbering (2 slit block on each plate currently (April 2007) are like this). It is not practical to mechanically alter either position so each of the two fibre numbers (slit position and Pivot position) are propagated in the binary table extension.
> >	There are two very important, and very different, numbers to understand in order to recover the information on which object each fibres was allocated to: Fibre slit position AND 2dF Fibre-Pivot position. For the most part there is a one-to-one correspondence between these numbers. i.e. the fibre at AAOmega slit position 1 (bottom of the CCD image) will map directly to 2dF Pivot position 1, and fibre 400 will map to Pivot position 400. (Notice 400 is a guide fibre and so maps to a blank space at the top of the CCD image). However, during manufacture or repair of the AAOmega slit units, it is possible for the order of fibres in each of the AAOmega slits to fall out of synchronization with the 2dF Pivot numbering (2 slit blocks on each plate are like this as of April 2007). It is not practical to mechanically alter either position so each of the two fibre numbers (slit position and Pivot position) are propagated in the binary table extension.

Changed:
< <	In the primary image (and also the variance array, stored in the first) the fibre at the bottom of the image, which is the fibre at slit position, corresponds to the first row in the binary table extension (the second FITS). The table contains a column entry, PIVOT, which gives the 2dF pivot position for this fibre. This is the fibre number seen be the Configure software. The very top fibre in a CCD image corresponds to the very last entry in the binary table (which will be an AAOmega guide fibre in the case of a single AAOmega data set). There is ALWAYS a one-to-one correspondence between each spectrum position in the image and the binary table. There is typically a one-to-one correspondence between slit position and 2dF pivot position but with a number of known mismatches and discontinuities which are tracked via the PIVOT column of the binary table.
> >	In the primary image .fits[0] (and also the variance array .fits[1]) the fibre at the bottom of the image, which is the fibre at slit position, corresponds to the first row in the binary table extension .fits[2]). The table contains a column entry, PIVOT, which gives the 2dF pivot position for this fibre. This is the fibre number seen be the Configure software. The very top fibre in a CCD image corresponds to the very last entry in the binary table (which will be an AAOmega guide fibre in the case of a single AAOmega data set). There is ALWAYS a one-to-one correspondence between each spectrum position in the image and the binary table. There is typically a one-to-one correspondence between slit position and 2dF pivot position but with a number of known mismatches and discontinuities which are tracked via the PIVOT column of the binary table.
	Combining Multiple AAOmega Data Sets which contain a Common Subset of Targets
Line: 72 to 69
	How to Access the FITS Binary Table Information
Changed:
< <	This list is not exhaustive. If your favorite option is missing, send an e-mail to Rob Sharp and we'll add it to the list.
> >	This list is not exhaustive. If your favorite option is missing, send an e-mail to Rob Sharp and it will be added to the list.
	With Configure
Changed:
< <	One can save a list file (file menu -> ..list) which contains the allocated 2dF Fibre-Pivot number for each allocated fibre. Note, this is the Pivot number for 2dF NOT the fibre number in the reduced 2D spectra file.
> >	One can save a list file (file menu -> ..list) which contains the allocated 2dF fibre Pivot number for each allocated fibre. Notice this is the Pivot number for 2dF, NOT the fibre number in the reduced 2D spectra file.
	Within 2dfdr

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Difference: AAOmegaFileFormat (4 vs. 5)

Revision 52007-04-22 - RonHeald

AAOmega File Format (or, which spectrum is which object?)

An Important Note on 2dF Fibre-Pivot Number and 2dfdr Fibre Number

Combining Multiple AAOmega Data Sets which contain a Common Subset of Targets

How to Access the FITS Binary Table Information

With Configure

Within 2dfdr