Difference: HifiCalibrationWeb (98 vs. 99)

Revision 992016-04-04 - DavidTeyssier

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META TOPICPARENT name="WebHome"

HIFI instrument and calibration web page


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NEW NEW NEW Latest updates -- 14 December 2015 NEW NEW NEW
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NEW NEW NEW Latest updates -- 4 April 2016 NEW NEW NEW
 
  • HIPE 14.0 has been released
  • Check the important calibration updates and associated improvements expected in the HIPE 14 reprocessed data- this includes in particular updated sideband gain ratio in bands 1 to 4
  • The HIFI products now come with a frequency-dependent intensity calibration uncertainty budget
  • Channel flags for spurs are now populated in all HIFI observations (this was limited to spectral scan up to HIPE 13)
  • Re-organisation of the HIFI quality flags for a better assessement of issues being relevant or not to the end products
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  • Users wishing to import their HIFI data into Gildas/CLASS can now do it directly with the Gildas oct15 release without the need of any previous conversion
 

Observing with HIFI

  • Useful Documentation
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Which data would most benefit from being reprocessed in HIPE 14.0?

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If your data have been processed with the latest bulk reprocessing (13.0), HIPE 12.0 or HIPE 11.1
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If your data have been processed with the latest bulk reprocessing (13.0), HIPE 12.0 or HIPE 11.1
 
  • Intensity calibration uncertainty
    • HIPE 14 introduces a new product providing an estimated breakdown of the intensity calibration uncertainty. The uncertainties are given separately for each component, as well as in a quadratic sum fashion for all statistically independent elements. This sum applies to the calibration of data in the Ta* scale. Further systematic and random error apply for data converted into different intensity scales (e.g. Tmb or Jy). See further details in section 9 of the DRG.
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  • Flags in OFF positions.
    • In HIPE 13 the data used in the OFF positions were already processed up to an equivalent Level 2 calibration (both in intensity and frequency) in order to be directly comparable to the ON-target data. In HIPE 14, those OFF spectra will also hold spur and warning flags that will be propagated from the ON-targert ones. This feature is for example very interesting in order to perform a deconvolution of the OFF spectras in a spectral scan and be able to compare the OFF spectra to the level 2.5 deconvolved products of those observations.
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If your data have been processed with a version earlier than 11.1
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If your data have been processed with a version earlier than 11.1
 
  • Solar System Object ephemerides
    • A bug (see here) was fixed in the calculation of SSO ephemeris positions (ra_centre/dec_centre) that led to offsets of up to ~10". This bug affected users that use cubes in a co-moving frame (including the standard Level 2.5 cubes), use the doOffset task, or make explicit use of ra_centre / dec_centre in their HIPE scripts. The offset is practically constant over a map and could, e.g., make the emission of a comet appear to be off-center when it really isn't. The fixed bug is in the Level 0 pipeline, which users cannot run easily. The issue was fixed in HIPE 11.1.
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If your data have been processed with a version earlier than 10.3
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If your data have been processed with a version earlier than 10.3
 
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  • DBS Observations If you have data processed with < HIPE 10
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  • DBS Observations If you have data processed with < HIPE 10
 
    • A new pipeline step, mkDbsReference, calculates the differences in the chop positions in all DBS observations, and after applying the band-pass correction, stores them in a product in calibration->pipeline-out called ReferenceSpectra. This allows you to check for contamination in chop positions for all types of DBS observations.
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  • Improved pointing reconstruction for observations taken between OD 320 and 761 If you have data processed with < HIPE 9
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  • Improved pointing reconstruction for observations taken between OD 320 and 761 If you have data processed with < HIPE 9
 
    • The pointing information attached to the data for observations taken between OD 320 and OD761 did not use the most accurate representation of the star tracker focal length. This was done for the bulk reprocessing with HIPE 9. As a consequence, some observations will experience a shift in astrometry, that can be as high as 8 arcsec. Details about the consequences for a particular obsid, and recipes to reconstruct the improved pointing yourself can be found at http://herschel.esac.esa.int/twiki/bin/view/Public/HowToUseImprovedPointingProducts as well as in the Level 0 section of the HIFI Data Reduction Guide.
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  • Backfilling of observational parameters If you have data processed with < HIPE 9
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  • Backfilling of observational parameters If you have data processed with < HIPE 9
 
    • From 9.1 onwards, most of the observational parameters that got optimised in HSpot will be propagated into the observation context, under a new product called HifiUplinkProduct (in the auxiliary product branch). Some of these parameters will be used in the pipeline to e.g. estimate the dimension of the cubes in the mapping and have them more representative of how the map was really obtained.
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  • Solar System Object maps If you have data processed with < HIPE 9
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  • Solar System Object maps If you have data processed with < HIPE 9
 
    • Cubes for moving targets are now created in the comoving frames in HIPE 9. In order to benefit from that, you should re-pipeline from Level 0 up to Level 2.5. Note that the hifiPipeline task should be called with the option "Aux=True". Please check the Pipeline chapter of the HIFI Data Reduction Guide for more details about how to do that.
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<!--* Calibration of data in bands 2a, 5a and 5b If you have data processed with < HIPE 8
* Un-balanced sideband gains will apply for some ranges of these bands (see also the calibration section). Reprocessing data from band 2a is recommended if your data are still processed with HIPE 6. Reprocessing data from band 5a and 5b is recommended if your data are processed with HIPE 8.

* Spectral Scan Data in bands 6 and 7 If you have data processed with < HIPE 8
* It is recommended to reprocess spectral scan data taken in band 6 and 7 if they are still processed with HIPE <8. This is not needed in data processed with HIPE 8 onward.
* Reprocessing with HIPE 9 onward will create a new Level 2.5 product containing a deconvolved single-sideband spectrum for each applicable spectrometer

* Maps If you have data processed with < HIPE 8
* Spectral cubes from mapping observations after OD 835 gridded using actual scan line and readout used in observation, earlier maps use a better approximation than in HIPE 7. These improvements are a consequence of changes in the Level 0 pipeline to read in information about how the observation was performed and require the pipeline to be re-run after running the doUplink step:

<verbatim>
from herschel.hifi.pipeline.level0 import DoUplink
doUplink=DoUplink()
backend = "WBS-V"
htp=obs.refs["level1"].product.refs[backend].product
htp1=doUplink(htp=htp.copy(), auxiliary=obs.getAuxiliary())
l1=obs.refs["level1"].product
l1.setProduct(backend,htp1)
obs.setProduct("level1",l1)
obs = hifiPipeline( obs=obs, fromLevel=1, upToLevel=2.5,save=0,apids=[backend])
#
# Now repeat replacing backend with "WBS-H", "HRS-H", "HRS-V"
</verbatim> -->
 
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-- DavidTeyssier , CarolynMcCoey, SylvieFBeaulieu and RengelMiriam - 14 December 2015 -
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-- DavidTeyssier , CarolynMcCoey, SylvieFBeaulieu and RengelMiriam - 4 April 2016 -
 
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