This page (revision-7) was last changed on 07-Dec-2016 14:14 by PeterYoung

This page was created on 07-May-2008 18:05 by PeterYoung

Only authorized users are allowed to rename pages.

Only authorized users are allowed to delete pages.

Page revision history

Version Date Modified Size Author Changes ... Change note
7 07-Dec-2016 14:14 5 KB PeterYoung to previous
6 19-Dec-2008 14:01 5 KB PeterYoung to previous | to last
5 18-Dec-2008 19:58 5 KB PeterYoung to previous | to last
4 18-Dec-2008 19:56 6 KB PeterYoung to previous | to last
3 17-Oct-2008 12:54 4 KB JianSun to previous | to last
2 21-May-2008 17:12 4 KB Gardini to previous | to last
1 07-May-2008 18:05 4 KB PeterYoung to last

Page References

Incoming links Outgoing links
Eis_prep
Eis_prep

Version management

Difference between version and

At line 1 added 2 lines
[{ALLOW edit EISMainUsers}]
[{ALLOW view Anonymous}]
At line 35 added 6 lines
For full CCD spectra, a different approach is used. Sections of the CCD have been identified where there are no (or very weak) emission lines and so it can be assumed that the background here represents a measure of the CCD background. The regions are then averaged to yield the background level which is subtracted from the spectra.
It is to be noted that both of these methods will yield some pixels with negative DN values. For window data it will only be 1 % of pixels because of the method used, but for full CCD spectra it can be up to 50 % of pixels if the raster contains very weak emission (e.g., coronal holes or off-limb spectra). ''The default mode for eis_prep sets pixels with zero or negative DN values to be missing data.'' This is because it is not possible to assign a photon noise error to the data points. (Note that negative DN values are expected since, if there are zero solar counts, then the uncertainty in the CCD counts will be 0 +/- read noise.)
By setting the /RETAIN keyword in eis_prep, pixels with zero or negative DN values will not be flagged as missing. The errors for the pixels will be set to the dark current error estimate (see Step 6).
At line 40 changed 2 lines
Spectrometer (CDS) data-sets (Thompson et al., 1998; Pike
& Harrison, 2000). For CDS data processing it was typical
Spectrometer (CDS) data-sets ([Thompson et al., 1998|http://solar.bnsc.rl.ac.uk/swnotes/cds_swnote_46.pdf]; [Pike
& Harrison, 2000|http://adsabs.harvard.edu/abs/2000A%26A...362L..21P]). For CDS data processing it was typical
At line 69 changed one line
mark the hot and warm pixels as missing data.
mark the hot and warm pixels as missing data. \\
Please also check the post [Top and bottom of hot/warm pixels maps|TopBottomHotWarmMaps] for more details.
At line 87 changed one line
with an error estimate of the dark current of 2.5 DN.
with an error estimate for the dark current. This varies from 2.24 to 2.37 DN for the four CCD quadrants.
This page (revision-7) was last changed on 07-Dec-2016 14:14 by PeterYoungTop