# Difference between revisions of "Scanning Beams"

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At the present time, HFI is not releasing the Scanning Beams. | At the present time, HFI is not releasing the Scanning Beams. | ||

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+ | ==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 gexpressed 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 contain 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 | ||

+ | |- | ||

+ | |UNIT || String || || Units of signal || Only HFI, LFI always K<sub>cmb</sub> | ||

+ | |- | ||

+ | |DESTRIPE || 1/0 || || whether timeline is destriped || Only HFI | ||

+ | |- | ||

+ | |OD || Int || || OD covered (as in filename) || | ||

+ | |- | ||

+ | |BEGIDX || Int || || first sample index of given OD || Only HFI | ||

+ | |- | ||

+ | |ENDIDX || Int || || last sample index of given OD || Only HFI | ||

+ | |- | ||

+ | |BEGRING || Int || || first ring in given OD || Only HFI | ||

+ | |- | ||

+ | |ENDRING || Int || || last ring in given OD || Only HFI | ||

+ | |} | ||

+ | |||

+ | |||

+ | |||

+ | |||

+ | * 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 contain the sequence of Nphi Stokes parameters for each <math>\theta</math>. | ||

The stokes map files consist in four columns containing the Stokes parameters for each sample. | The stokes map files consist in four columns containing the Stokes parameters for each sample. | ||

The columns are called "Beamdata" , "BeamdataQ", "BeamdataU" and "BeamdataV", containing respectively <math>I</math>, <math>Q</math>, <math>U</math> and <math>V</math>. | The columns are called "Beamdata" , "BeamdataQ", "BeamdataU" and "BeamdataV", containing respectively <math>I</math>, <math>Q</math>, <math>U</math> and <math>V</math>. | ||

There are differences in the data format between the Main Beam and the near and far Sidelobes. | There are differences in the data format between the Main Beam and the near and far Sidelobes. | ||

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## Revision as of 11:11, 2 February 2015

We released maps of the Stokes parameters of the band-averaged scanning beams. The Stokes parameters maps contain the complete information about the field intensity and polarization properties. Main Beam, Intermediate Beam, and Sidelobes are released separately.

## File Names[edit]

The file names are of the form:

*LFI_ScanBeam-{mb,ib,sl}_{fff}-{rrr}_R2.{nn}.stokes*

where

*fff*denotes the frequency- mb denotes the Main Beams
- ib denotes the Intermediate Beam
- sl denotes the Sidelobes
*rrr*denotes the radiometer- R2.nn is the version.

At the present time, HFI is not releasing the Scanning Beams.

## FITS file structure[edit]

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*BeamdataQ*, containing*BeamdataU*, containing*BeamdataV*, containing .

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 gexpressed 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 contain the sequence of the *Xcentre* and *Ycentre* express the coordinates of the beam maximum (i.e. where the sphere intersect the tangent plane).

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 | |

Keyword | Data Type | Value | Description | Comment |

UNIT | String | Units of signal | Only HFI, LFI always K_{cmb} | |

DESTRIPE | 1/0 | whether timeline is destriped | Only HFI | |

OD | Int | OD covered (as in filename) | ||

BEGIDX | Int | first sample index of given OD | Only HFI | |

ENDIDX | Int | last sample index of given OD | Only HFI | |

BEGRING | Int | first ring in given OD | Only HFI | |

ENDRING | Int | last ring in given OD | Only HFI |

- Intermediate Beams and Sidelobes are sampled on the sphere. The resolution in and is given by the keywords "Ntheta" and "Nphi". The columns contain the sequence of Nphi Stokes parameters for each .

The stokes map files consist in four columns containing the Stokes parameters for each sample. The columns are called "Beamdata" , "BeamdataQ", "BeamdataU" and "BeamdataV", containing respectively

, , and . There are differences in the data format between the Main Beam and the near and far Sidelobes.(Planck) Low Frequency Instrument

(Planck) High Frequency Instrument

Flexible Image Transfer Specification

Operation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day.