The orientation of the plot is such that north is up and east is to the left.
NEOCP.stg. This is a plain text file which contains
observation requests for each of the NEOCP objects which are observable in the
current night or will be observable in the coming night (as seen from the specified
observing station). This file can either be directly processed by the
TAO scheduler, or its contents may be
pasted into a larger file containing observation requests in the
appropriate format. In this way, a complex search
campaign can be planned and started in a very short time. A sample
NEOCP.stg file is given below:
U04889; PRH &
PA=38.5 width=3.50 overlap=1.50 dRA=.00465 ddec=-.00106 &
0 0 &
-1 0 &
1 0 &
0 1 &
1 -1 &
-1 1 &
AJ20067; PRH &
PA=343.1 width=3.50 overlap=1.50 dRA=-.05926 ddec=0.22600 &
The above file specifies a 7-field search mosaic for object U04889.
In the observation request for this object, PA specifies the
position angle (in degrees) of the major axis
of the confidence ellipse (PA is measured from north through east,
from 0 to 360 deg), width and overlap
have the same values specified in NEOCPMon.cfg, and
dRA and ddec are the offsets of the
center of the confidence ellipse (blue dot) with respect to the nominal NEOCP prediction
(green dot), measured in hours and degrees, respectively. The values of
(i,j) corresponding to the search
fields plotted on the corresponding PostScript plot are also listed.
No uncertainty information was given for DjIB1i on the NEOCP
(since it had already been confirmed on a second night after discovery), so a single field
is requested for this object, centered at the nominal NEOCP ephemeris position.
an uncertainty map which could be covered with a single CCD field; however, for better
centering of the uncertainty map within the CCD field, the field center is offset from
the nominal NEOCP ephemeris by -0.05926 h in right ascension and 0.226 deg in
- If one feels that not all search fields selected by NEOCPMon are
worth searching (or if there is not enough telescope time available to
search all listed fields), the undesired fields can be deleted from
NEOCP.stg. For example, if one does not wish
to image field (1,1)
of the above sample plot for U04889, the last line of the observation request
for U04889 in NEOCP.stg might be removed (along
with the & character on the preceding line).
- Analogously, if one wishes
to search fields which have not been selected by NEOCPMon,
one can either increase the confidence level
in NEOCPMon.cfg and rerun the script to generate new
PostScript plots and a new NEOCP.stg files with more
selected search fields, or add extra fields by hand to
- One important remark to have in mind is that the mosaic of search fields
generated by NEOCPMon moves with the object in consideration: the offset of a
given field in the diagram is to be interpreted as the offset with respect to the
nominal NEOCP ephemeris at the time the field is actually observed. Since NEOCP objects
may move very fast, and it takes a finite amount of time to perform a search campaign,
if one plotted the searched fields on a right ascension vs. declination diagram, the
fields would probably exhibit a configuration which is different from the one in the
PostScript plot. In particular, there might be holes in between the fields. This is
not a defect of the algorithm: a little thought shows that computing the
offsets of the search fields in the above mentioned way is equivalent to a hypothetical
(but impracticable) simultaneous search of all the selected search fields.
- On the other hand, the accuracy of NEOCPMon's mosaic-building algorithm is limited
by the fact that it only uses data from an uncertainty map for a fixed time.
This is chosen to be the time when the object reaches its highest altitude as
seen from the observing station during the current or coming night.
Uncertainty maps change with time, although they usually don't change much over a period
of a few to several hours. For this reason, the search mosaics produced by
NEOCPMon are usually quite accurate even for fast-moving NEOs, especially if
they are observed near the times when they reach their maximum altitudes as seen
from the observing station.