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The Target Form

 

For every requested pointing direction a target form must be filled out.

1. In the Target item every pointing direction must be identified first with a target number, and second with a target name; an alternate name can also be given. Note that the target numbers should run consecutively from 1 to the ``Number of Targets'' entry as specified on the cover page. The target numbers should be assigned in a priority order in such a way that those targets which are most important for success of the proposed research should be enumerated first. If observing time is cut by the national proposal selection committees, an attempt will be made to keep the pointings with higher priority in the target list. The Right Ascension and Declination of the requested pointing position must be specified in coordinates with the equinox 2000 . Note that this position will be used for the actual pointing of the satellite. Principal Investigators should therefore carefully check the requested pointing direction and consider whether positional uncertainties can compromise the desired scientific results. This is particularly relevant for observations with the HRI, which loses sensitivity at rather small off-axis angles. Furthermore note that the actual pointing position may differ from the requested and scheduled pointing position by up to 3 arcminutes (see Chapter 3 ).
2. In the Instrument Configuration item the ``total observing time'' entry denotes the total requested observing time for the specified pointing direction (in kilo-seconds). Note that this number may be changed by the national selection committees. The ``number of observations'' entry determines how many RORs (see § 8.3 ) will be generated from the target form. The ``Additional Constraints'' entry indicates whether special scheduling constraints (i.e., constraints for time-critical observations) apply or not. If this entry is ``Y(es)'', an ``Observational Constraint Form'' must accompany the source form. Note that the number of observations can only be larger than one if additional scheduling constraints exist. The ``WFC Zoom On'' entry requests a small or large WFC field of view (cf., § 5.3  for details); it is strongly suggested to use the ``NOZOOM'' option for all filters unless there are very specific reasons to do otherwise. The requested instrument configuration is determined by assigning an instrument code to each of the three available instruments (HRI, PSPC and WFC) in the following way: The primary instrument is denoted by the entry ``1'', the secondary instrument by the entry ``2'', and the instrument not to be used by the entry ``0''. The various possible combinations are listed in Table 9.1 . Note that Principal Investigators from the US must not select the WFC as primary instrument and that PSPC and HRI are mutually exclusive.

    

   PSPC HRI WFC Comments

   PSPC+WFC 1 0 2

   HRI+WFC 0 1 2

   WFC+PSPC 2 0 1 only non-US proposers

   WFC+HRI 0 2 1 only non-US proposers

   For both the PSPC and the WFC, different filter settings can be chosen (see Chapter 4  and Chapter 5 ). However the number of filter changes during the execution of any ROR is limited to one for the PSPC. WFC filter changes more frequent than about once per 1000 s should not normally be requested; for a limited number of observations a higher frequency may be permitted if judged to be of sufficient scientific merit. The requested filter sequences can be specified in items 4. PSPC Filter Sequence and 5. WFC Filter Sequence below and will be scheduled - if at all possible - in the order as specified by the guest investigator with the percentages (in terms of total requested time) specified in the target form. It is important to note that the specified sequence implies a priority order. If the total time allocated to the proposal is reduced for any reason (for example, by the decision of the selection committee), the observation will be carried out with the times allocated to each filter according to the requested percentages, unless the time implied falls below the minimum time requested. In this case the specific filter will not be selected and the total time will be distributed among the remaining filters according to the percentages specified. Observers who wish not to run the risk of an observation with any particular filter being dropped out should specify a minimum useful time of zero for all filters in the minimum time entry. US proposers (who have no proprietary data rights to the WFC) are encouraged but not requested to fill out the WFC items.

3. In the PSPC Filter Sequence item the requested PSPC Filter sequence is specified; obviously this item needs only to be filled out if PSPC observations are requested either as primary or secondary instrument. Use the Filter identifications ``OPEN'' and ``BORON'' to indicate whether PSPC observations in the OPEN position or with the boron filter are requested. In case no filter change is requested, use the ``OPEN'' filter identification with percentage time set to 100 percent and minimum time set to zero.
4. In the WFC Filter Sequence item the requested WFC filter sequence is specified; US observers may choose to suggest a WFC filter sequence, but it cannot be guaranteed that the specified sequence will be scheduled. Use the Filter identifications ``S1'', ``S2'', ``P1'', ``P2'', and ``OPQ'' (see § 5.1  for details) to indicate the filters of your choice. If only a single filter is desired provide the appropriate filter identification with percentage time set to 100 percent and minimum time set to zero.
5. The Remarks entry provides room for special remarks; note that it cannot be guaranteed that any requests spelled out in this entry will be taken into account.