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Дата изменения: Fri Feb 23 14:02:50 1996 Дата индексирования: Tue Oct 2 18:57:31 2012 Кодировка: Поисковые слова: comet |
Table shows a table of association rules that has been
created to associate bias exposures with scientific frames.
A column labeled :MJD_LOC has been created in the OST and contains a number
derived from the Modified Julian Date of the exposure.
The graphs of Figure illustrate the association of two dark
exposures with each of two scientific images from our observing run:
susi0006.bdf and susi0009.bdf.
The association process when applying the set of criteria mentioned above will
find two suitable candidates for susi0006.bdf satisfying the ``first choice" set of criteria. No ``first choice" candidates for susi0009.bdf will be found while
five ``second choice" candidates may be selected. Because more importance
is assigned to the time difference (weight=0.8) than to the detector temperature
difference (weight=0.2), the files susi0001.bdf and susi0002.bdf will be
flagged as the ``best" ones. (Note that the differences are computed in the
units involved in the columns involved. In the given example they are degrees
kelvin and days, respectively.)
A table of rules (Table ) for associating flat-field exposures has been created
following the same scheme. One criterion has to be added to the rules
mentioned above:
One has to make sure that one associates only frames obtained
in the same instrument configuration (i.e in this case with the same filter).
Figure
shows that only one flat field can be associated with
the frame susi0006.bdf (for clarity, only the FFs obtained with the same filter
as the scientific image are numbered) while three suitable flat-fields may be
selected for susi0009.bdf
Table: Rules for the association of DARK exposures (cf. Fig. and
)
Table: Rules for the association of FF exposures (cf. Fig. and
)