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: http://xmm.vilspa.esa.es/calibration/documentation/CALHB/node560.html
Дата изменения: Tue Sep 20 19:45:20 2011 Дата индексирования: Mon Apr 11 03:11:08 2016 Кодировка: Поисковые слова: helix nebula |
FILTERID1 | FILTERID2 | priority |
B | V | 1 |
U | V | 2 |
UVW1 | V | 3 |
UVW2 | V | 4 |
U | B | 1 |
UVW1 | B | 2 |
UVW2 | B | 3 |
UVW1 | U | 1 |
The colour indices of the correction terms (mag-mag
)
are always defined as (shorter wavelength passband - longer wavelength passband),
e.g. (u-b), (b-v) or (uvw1-u) etc.
A new keyword ALGOID is used in the CCF to associate parameters sets with different algorithm. An ALGOID keyword value of 1 corresponds to the transformation described in this version (2.0 or later) of the calibration handbook. An ALGOID keyword value of 0 corresponds to transformation as described in calibration handbook version 1.1 or earlier.
The CAL provides the following functionality (assuming the keyword ALGOID has a value of 1):
The colour transformation can only be applied when a transformation exists between the specified filters filter1 and filter2 with the colour (mag1-mag2) falling within the validity range of the colour transformation equation and if the specified transformation branch branch is listed in the COLORMAG extension of the CCF ColorTrans component.
The colour in the
instrumental system (mag1-mag2) must fall within
the validity range of the colour transformation:
![]() |
defines the validity range of the colour transformation as defined in the column |
TRAFOLIMIT of the ColorTrans CCF component. | |
mag1-mag2 | the colour index calculated from the two input magnitudes in the instrumental |
system. |
![]() |
value in column BRANCH in the COLORMAG extension of the CCF |
ColorTrans component. | |
branch | value of optional input parameter |
The transformation of the colour term (mag1-mag2)
into a standard system is described by the equation
![]() |
are the parameters stored in the TRAFOP1 column of the ColorTrans CCF |
component. | |
mag1-mag2 | the colour index calculated from the two input magnitudes in the instrumental |
system |
The transformation of the instrumental magnitude mag2
into the magnitude MAG2 of a
standard photometric system is described by the equation:
![]() |
are the parameters stored in the TRAFOP2 column of the |
ColorTrans CCF component. | |
mag1-mag2 | the colour index calculated from the two input magnitudes |
in the instrumental system | |
mag2 | brightness in the instrumental system of filter2 |
MAG2 | brightness in the standard system of filter2 |