The staring raster mode was a sequence of staring observations (i.e. chopping was not allowed) on a two-dimensional regular grid which consisted of a sequence of spacecraft pointings. The detector setting remained unchanged for all pointings. The orientation of the raster could be chosen either aligned with the spacecraft y-axis orientation and hence the detector array orientation, or with regard to the sky N-direction, i.e. in general independently of the spacecraft orientation. However, in the latter case the observed sky region was not always completely sampled (for example see Figure 3.5).
![\resizebox {12cm}{!}{
\includegraphics*[120,353][450,670]{c200projection.ps}}](img108.gif)
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Studies of point sources on complex backgrounds or extended sources (sizes of more than 3 arcmin) were possible with this observing mode. This mode was the only one for mapping with PHT-P.
The maximum number of raster points was 
. The maximum raster
step size was 180
Therefore, the maximum sampling area was
.
In the beginning the minimum raster step size was half the aperture
size and one quarter of the array size. Later in the mission (from
17-Oct-1996, revolution 3363.3) the
minimum raster step size was reduced to `On-target-flag threshold'
plus 
in the case of PHT-P and -S and 
for both
C-arrays. Since the `On-target-flag threshold' was reduced to
in the end, raster step sizes as small as 
were possible, which allowed highly oversampled PHT-P rasters
(for example: Heinrichsen, Walker & Klaas 1998,
[16]).
A special raster mode was the so-called `telescope nodding' allowing
to perform a slow off-on-off-on-off-... modulation similar to
triangular (M= 3, 5, 
) and rectangular (M= 2) chopping.
By selecting a raster step size of 
in between
raster legs (
) and more than 1 raster leg (
)
the telescope performed a nodding observation.