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<H3><A NAME="SECTION003511600000000000000">
<TT>TESTC/CCD</TT></A>
</H3>
This command produces an estimate of the bulk charge transfer efficiency
in the horizontal (HCTE) and vertical direction (VCTE) (by the EPER
method (Janesick et al., 1987)).
For the HCTE the command first averages the rows given as the second
parameter. The command uses the number of image pixels, the last
image pixel and the first bias overscan pixel is obtained and
computes the HCTE according to the formula:
<BR><P></P>
<DIV ALIGN="CENTER">
<!-- MATH: \begin{equation}
HCTE = 1 - bc/ic*ni,
\end{equation} -->
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<I>HCTE</I> = 1 - <I>bc</I>/<I>ic</I>*<I>ni</I>,
</TD>
<TD WIDTH=10 ALIGN="RIGHT">
(27.2)</TD></TR>
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</DIV>
<BR CLEAR="ALL"><P></P>
where: <I>bc</I> are the counts above the bias level in the first
overscan pixel in a row; <I>ic</I> are the count above the bias
level in the last image pixel in a row; <I>ni</I> are the number
of image pixels in a row.
The values for the bias offset is extracted from the keyword
<TT>BIASMEAN</TT>, and is computed by the command <TT>TESTB/CCD</TT>.
To determine the image section of the CCD and the overscan regions
one can use the commands <TT>READ/IMAGE</TT>, <TT>PLOT/COLUMN</TT> and
<TT>PLOT/ROW</TT>.
<P>
Note that the last column of a row is often slightly brighter than
the rest of the row (because the pixel is slightly larger).
The vertical charge transfer efficiency is computed in a similar way.
<P>
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<ADDRESS>
<I>Petra Nass</I>
<BR><I>1999-06-15</I>
</ADDRESS>
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