AOT - Astronomical Observation Template: Representation of
an observing mode in the proposal generation software (PGA).
Background: Sky emission towards the direction of the source.
The contributors are: Zodiacal Light, diffuse galactic emission and
local diffuse emission in the vicinity of the source.
Drift: Time evolution of detector response.
Instrument mode: A mode in which the instrument can be
operated.
Exposure: a 32x32 pixel frame obtained after a readout of the
array following an integration of the signal of one elementary
integration time
Exposure time: Time during which the target is observed plus, in
the case of beam-switching observations, the time for measurements at a
reference position.
Image: a 32x32 pixel frame obtained after processing the
exposures of one observation.
Integration time: The time during which the target is observed.
Time for observing a reference field is not included (cf. Exposure
time).
Micro-scan: A scan which involves short spacecraft slews,
within a raster.
Observing mode: An instrument mode dedicated to a specific
type of astronomical observation.The representation of an
observing mode vis-a-vis the observer is an AOT.
Orientation: Angular distance of direction of a scan line.
Counted anticlockwise
from North.
Overhead: Time to prepare the spacecraft and instrument for
an observation, e.g. array stabilization, wheel positioning and spacecraft
slews.
Point spread function: The flux distribution due to diffraction
in the image of an ideal point-like source as seen by the telescope
optics at a specific wavelength.
Pointing: Positioning of spacecraft at a required sky
position.
Proposal Generation Aids - PGA: The ISO software system to
enter proposals in submission phase II. It consists of a data base
management system with a user interface of panels.
Raster: A series of regularly spaced pointed observations,
where at each position the observation is repeated. It is defined by
the centre position and the step sizes in R.A. and Dec.
Readout: One measurement of the current output voltage
before resetting a pixel or after integrating the signal.
Reference beam or Reference field: A position adjacent
to the source usually to determine the background emission.
Scan, Scan line or Scan leg: A series of spacecraft
pointings in one dimension, where the positions between two
spacecraft pointings are obtained by chopping. A scan is defined by
the orientation and the tolerance angle.
Sky bin: A portion of the sky which is 10 by 10 degrees. The
division of the sky in finite bins facilitates the calculation of
visibility of the sky.
Step size: Distance between two points in a raster and
between scan lines to define the size of the raster.
Target dedicated time: The time spent for the observation of
a source in an observing mode including integration time and
overhead times.