This page (revision-11) was last changed on 07-Dec-2016 14:14 by PeterYoung

This page was created on 14-May-2007 13:16 by Louise Harra

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Version Date Modified Size Author Changes ... Change note
11 07-Dec-2016 14:14 2 KB PeterYoung to previous
10 14-Jun-2010 15:54 3 KB PeterYoung to previous | to last
9 26-Jan-2009 05:53 1 KB David R Williams to previous | to last
8 26-Jan-2009 05:53 1 KB David R Williams to previous | to last Deleted the current-time stamp which gave the wrong date for David's contribution.
7 20-Sep-2007 19:36 2 KB David Pérez-Suárez to previous | to last
6 31-Aug-2007 14:15 888 bytes LouiseHarra to previous | to last
5 31-Aug-2007 14:14 1 KB LouiseHarra to previous | to last
4 14-May-2007 16:45 900 bytes Louise Harra to previous | to last
3 14-May-2007 16:18 828 bytes Louise Harra to previous | to last
2 14-May-2007 13:42 829 bytes Louise Harra to previous | to last
1 14-May-2007 13:16 828 bytes Louise Harra to last

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OrbitalVariationLinePosition
OrbitalVariationLinePosition

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There is a shift of the spectral line position during the orbit. This is due to the thermal changes occuring across the instrument during the orbit and was an expected effect. We are currently collecting data that will allow us to model this accurately for correction. As well as orbital variation, there will be seasonal variation as well. In the meantime, especially when dealing with rasters, you must correct for this. An uncorrected velocity map looks like the attachment, where you can clearly see the change in red and blue shift during the orbit. Software is being produced to correct for this but is not within eis_prep. Following testing it will be released to SSW. In the meantime you can correct for the variation by modelling the line position along the time direction and subtracting that component which is sinusiodal in shape. [Orbitfiles | OrbitalVariationLinePosition/orbital.jpg]
One routine that has been added to SSW to deal with the oribital correction is eis_orbit_correction written by Peter Young.
There is a shift of the spectral line position during the orbit. This is due to the thermal changes occuring across the instrument during the orbit and was an expected effect. We are currently collecting data that will allow us to model this accurately for correction. As well as orbital variation, there will be seasonal variation as well. In the meantime, especially when dealing with rasters, you must correct for this. An uncorrected velocity map looks like the attachment, where you can clearly see the change in red and blue shift during the orbit. Software is being produced to correct for this but is not within eis_prep. It is now released to SSW (eis_orbit_correction). You can correct for the variation by modelling the line position along the time direction and subtracting that component which is sinusiodal in shape. [Orbitfiles | OrbitalVariationLinePosition/orbital.jpg]
This page (revision-11) was last changed on 07-Dec-2016 14:14 by PeterYoungTop