View source for Scanning Beams

===FITS file structure===
The FITS files contain a primary extension with no data and a minimal header, and one BINTABLE extension with data and with a description of the data in the header keywords. 
The BINTABLE extension consist in four columns, each containing the array of one Stokes parameter. 
The columns are called:
* ''Beamdata'' , containing <math>I</math>
* ''BeamdataQ'', containing <math>Q</math>
* ''BeamdataU'', containing <math>U</math>
* ''BeamdataV'', containing <math>V</math>.

Main Beam, Intermediate Beams and Sidelobes are saved with a different data format: 

* Main Beams are projected on the tangent plane to the sphere, and sampled on a grid. The grid include an angular region expressed by the keyword ''angularCut'', and its dimensions are given by the keywords ''Nx'' and ''Ny'', representing the number of columns and rows. Each column of the BINDATA extension contains the sequence of the <math>Nx \times Ny</math> samples of the map in row major order. The keywords ''Xcentre'' and ''Ycentre'' express the coordinates of the beam maximum (i.e. where the sphere intersect the tangent plane).

{| border="1" cellpadding="3" cellspacing="0" align="center" style="text-align:left" width=800px
|+ '''Main Beam file structure''' 

|- bgcolor="ffdead"   
! Column Name || Data Type || Units || Description || Comment
|-
|BEAMDATA || Real*4 || none  || Stokes parameter I || 
|-
|BEAMDATAQ || Real*4 || none || Stokes parameter Q ||
|-
|BEAMDATAU || Real*4 || none || Stokes parameter U ||
|-
|BEAMDATAV || Real*4 || none || Stokes parameter V ||

|- bgcolor="ffdead"   

! Keyword || Data Type || Value || Description || Comment
|-
|Nx ||  Int || 601 || X axis samples number || X axis aligned with the direction of the S arm
|-
|Ny ||  Int || 601 || Y axis samples number || Y axis aligned with the direction of the M arm
|-
|Xcentre ||  Int || 301 || X coordinate of the beam centre ||
|-
|Ycentre ||  Int || 301 || Y coordinate of the beam centre || 
|-
|Xdelta ||  Float ||  || X step in radians || 
|-
|Ydelta ||  Float ||  || Y step in radians || 
|}



 
* Intermediate Beams and Sidelobes are sampled on the sphere. The resolution in <math>\theta</math> and <math>\phi</math> is given by the  keywords "Ntheta" and  "Nphi". The columns of the BINDATA extension contain the sequence of Nphi Stokes parameters for each <math>\theta</math>.

{| border="1" cellpadding="3" cellspacing="0" align="center" style="text-align:left" width=800px
|+ '''Intermediate Beam and Sidelobes file structure''' 

|- bgcolor="ffdead"
! Column Name || Data Type || Units || Description ||Comment
|-
|BEAMDATA || Real*4 || none  || Stokes parameter I || 
|-
|BEAMDATAQ || Real*4 || none || Stokes parameter Q ||
|-
|BEAMDATAU || Real*4 || none || Stokes parameter U ||
|-
|BEAMDATAV || Real*4 || none || Stokes parameter V ||

|- bgcolor="ffdead"   

! Keyword || Data Type || Value || Description || Comment
|-
|Ntheta ||  Int ||  || <math>\theta</math> samples number || colatitude
|-
|Nphi ||  Int ||  || <math>\phi</math> samples number || longitude
|-
|Mintheta ||  Float ||  || Minimum value of <math>\theta</math> ||
|-
|Maxtheta ||  Float ||  || Maximum value of <math>\theta</math> ||
|-
|angularCut ||  Float ||  || Angular cut [deg] ||

|}