Caltech-Internal Target of Opportunity (ToO) Policy
Caltech Optical Observatories (COO) supports a Caltech-internal
Target of Opportunity (ToO) program to enable its
researchers to acquire data on unexpected, transient events by
allowing interruption of regularly scheduled programs of Caltech
observers at the Keck telescopes and the Palomar 200-inch
telescope. In such cases, the observer at the telescope is obliged to
set aside his or her program and make specific observations on behalf
of the ToO researcher.
Caltech-Internal ToO Program Policies:
The log of active and past ToO projects, go to
COO ToO Log.
NEW: ToO projects are restricted to Caltech
(and Northwestern -- see below)
researchers as designated by the appropriate selecting official.
Such projects must be among the applicant's highest priority
requests for time on the telescope involved.
NEW: ToO interrupts may be invoked only when a Caltech
(or Northwestern -- see below) is observing with the telescope.
All Caltech observers shall support requested interrupts from
authorized Caltech-Internal ToO program advocates.
NEW: Caltech's Keck Partnership with Northwestern includes Northwestern
participation in Caltech's internal ToO program on Keck Telescopes.
Keck ToO requests from designated Northwestern ToO program advocates
shall be supported by Caltech observers, and Northwestern Keck
observers shall similarly honor authorized Caltech ToO requests
(up to negotiated program limits).
- Each ToO interrupt should be restricted to a reasonable
total time per night so as not to undermine community support. A
maximum of 2 hours per night is suggested except in exceptional
circumstances. Shorter interrupts are the norm.
- There will be no payback time or other compensation for
- Unused time assigned to a ToO program will not be
carried forward to the next semester.
- All PIs who are allocated observing time will be given brief
details of the successful ToO programs from previous
- An override may be activated only when the available equipment
and moonlight conditions are consistent with the TAC
recommendations. Seeing and photometric conditions are not a
condition for any override.
- When a ToO PI wishes to activate her or his program, it
will be sufficient to telephone the observatory and describe the
requirements to the observer. Observers who are
supporting ToO observing must comply with the
request regardless of the state of her or his program after
completing the exposure then in progress and any necessary
calibration exposures that cannot conveniently be completed in
twilight. If the exposure is part of a longer sequence, that
sequence must nevertheless be curtailed.
- Interrupt time is measured from the completion of the regular
observer's exposure and necessary calibration, to the same point for
the ToO override.
The scheduled observer will send an e-mail to the ToO
PI [copies to S. Kulkarni (srk [at] astro.caltech.edu) and A. Boden
(bode [at] astro.caltech.edu)] immediately upon completion of the
observing run, reporting on the time devoted to ToO
observations and other relevant comments. The observer will deliver
the necessary data to the ToO PI. Similarly,
the ToO PI will send an e-mail to A. Boden
(bode [at] astro.caltech.edu) [copy to S. Kulkarni (srk [at] astro.caltech.edu)]
reporting on the time used for each interrupt, with an account of
the status of the ToO project. Finally, the ToO
PI will also report to the Director at the end of each observing
semester with a complete account of the status of
his/her ToO projects, time invoked, etc.
COO ToO Policy / v 0.2
Last updated: 27 February 2018 AFB/RJB/ACM