ASCA: Draft Rules for Targets of Opportunity (TOO)

This page describes the current policy and application procedure for a Target of Opportunity (TOO) with the ASCA Observatory. This policy was started in June 1997 to increase the participation and opportunities for TOOs with ASCA. Prior to this change TOOs had been taken exclusively from the Japanese time allocation, by replacing a Japanese target with the TOO and assigning a Japanese principal investigator (PI). TOOs will utilize the general observatory time, with the PI designated to be the person who first requested the TOO, following the procedure described below. This will allow more flexibility in the scheduling of TOO targets, and broaden the participation in the data analysis.

About 7% of the ASCA observation time is allocated to observatory time which includes not only TOOs, but also for calibration and completing under exposed observations. Of this time typically 250-350 Ksec/yr is available for TOOs. This means the current capability is about 10 TOO observations/year (20-40 ksec). The TOO observations are compensated by Priority-C targets at the end of an AO cycle.

As has been the case for other observatories, the TOO program is designed to provide quick response to observe unexpected events, that could not be anticipated as part of the regular proposal process. For an ASCA TOO request to be approved requires a strong scientific justification and a clear demonstration that it involves a historically rare event that cannot wait to be included in the next AO cycle review.

The TOO observation will be made during the first available opportunity. The operational constraints of ASCA (where uplinked commands can be made during contacts from Japan) mean that this will be at least 3 days after the request is made. The replaced target will be rescheduled in the current observing window if possible, otherwise in the next window typically six months later.

The guidelines to follow when applying for an ASCA TOO are as follows:

If you have any questions concerning the ASCA TOO policy or you wish to apply for a TOO please send e-mail to Fumiaki Nagase (nagase@astro.isas.ac.jp) and/or Nick White (white@adhoc.gsfc.nasa.gov)
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