Comments from the TAC
NOAO Newsletter No. 45, March 1996)
Several years ago the demand for dark time was largely composed of
proposals for observations of faint extragalactic objects, while the
bright time was primarily used for galactic objects and stellar
evolution programs. Since a separation by lunar phase also separated
the overall scientific areas of interest, KPNO convened two committees,
the "Bright" TAC and the "Dark" TAC with different areas of scientific
expertise to reflect this difference in demand.
The development of infrared arrays changed all this. We are now seeing
many proposals in bright time that require expertise in extragalactic
astronomy for proper evaluation. Similarly, the advent of wide field
CCD detectors gave rise to programs in dark time that addressed
problems in stellar populations in our own and nearby galaxies. The
composition of the two committees rapidly changed to reflect this new
demand, and both committees now have expertise in galactic and
extragalactic astronomy. However, the two committees still retain the
"Bright" and "Dark" names, and for the larger aperture telescopes the
proposals seen by each committee are still sorted by lunar phase. This
can cause some problems, particularly when a given program asks for
dark time on one telescope and bright time on another. Moreover, having
both galactic and extragalactic expertise on both committees means that
this expertise must be spread rather thinly if each committee is to be
an optimal size.
We have been aware of these problems caused by the evolution of the TAC
process and have been exploring options for addressing them. An
additional complication arises from the need to consider future demands
on the TAC process, such as inclusion of Gemini programs and review of
programs that may involve time at private observatories. Discussions on
this complex topic have been held at a special AURA workshop last
spring, with the combined KPNO/CTIO Users Committees during their fall
1995 meeting, and with each of the standing KPNO TACs. Options
discussed ranged from maintaining the status quo to establishing many
narrowly focused discipline-specific panels.
The general outcome of these discussions is one of evolutionary change
with an eye to future demands. Thus for the fall 1996 semester there
will again be two KPNO TACs, but they will be named "Galactic" and
"Extragalactic," with expertise concentrated in the appropriate areas.
The division between "Galactic" and "Extragalactic" is not always
clear. In general "Galactic" will include objects in our galaxy and the
Local Group. However, the Galactic committee will have general
expertise in stellar evolution and stellar populations, so proposals
that explore the evolution of stellar populations in distant galaxies,
if done spectroscopically, could go to the "Galactic" TAC. However,
stellar population studies at very high redshift that use wideband
photometry with multiple bandpasses would probably go to the
"Extragalactic" TAC. In order to assist us in sorting the proposals,
the proposal form will be revised to allow you to pick the category in
which you wish your proposal to reside. This change will not only
allow for a better match of expertise to programs for each TAC, it
will also allow one TAC to evaluate completely complex programs that
require several telescopes at different lunar phases.
After the TAC review, the telescopes will be scheduled as before. We
anticipate that the extragalactic programs will still demand most of
the dark time, and that this lunar phase will, for most telescopes, be
more heavily oversubscribed than bright time. Proposals with the
highest TAC grade will be given preference in terms of lunar phase.
We hope this change in the TAC procedure will produce an improved
review process. Please send us your comments on any aspect of our
proposal review program. We will continue to monitor its performance
and will make further changes in response to your comments and to
changes in our users' needs.
David De Young
(Extracted from NOAO Newsletter No. 41, 1 March 1995)
During the last series of telescope Time Allocation Committee meetings it
became clear that some individuals may have forgotten some of the
guidelines that should be followed in submitting observing proposals to
KPNO. As the next proposal submission cycle is approaching, now is an
appropriate time to point out some of these guidelines.
Long Term Status
The rules under which a proposal may be considered by the TAC for long
term status are fairly simple and well defined. In order to qualify for long
term status, a proposal must successfully argue that all of the data must be
obtained before the basic scientific question being posed can be answered.
Simply enlarging a sample for the sake of completeness or better statistics is
not sufficient. Put another way, a long term status project is one in which no
conclusions will be able to be drawn if, say, only half the observations are
made. In its simplest form it is an all or nothing criterion.
This is often a confusing issue. Having access to other facilities does NOT
preclude proposing to KPNO or jeopardize its discussion by the TAC. Many
successful KPNO observers also have access to other facilities. What the
TAC very much wants to see is the reason why observations are also needed
with KPNO telescopes. Such factors could be unique or complementary
instrumentation, darker site, coordinated observations involving other sites,
etc. Problems arise when it is known that the principal investigators or
co-investigators are affiliated with an organization that has access to other
facilities and yet there is no explanation given as to why there is also a need
to use KPNO telescopes. If such an affiliation exists but is not real, due to
internal organizational structure, this should be explained, as the TAC is
usually unaware of these internal restrictions.
The guideline for the length of the scientific justification is one page of
text plus figures. This criterion is often violated, sometimes flagrantly.
Violation of the length guideline may not be beneficial, as it can serve to
reduce the degree of benevolence with which a given TAC member may view a
proposal. Repeated offenses are often remembered. If a scientific program
is well defined and well thought out, a convincing justification can easily be
made to fit on one page and within the print size requirements.
Please be sure to use the current proposal submission form; we are still
receiving the occasional proposal on obsolete forms. Electronic submission,
which is described in an accompanying Newsletter article, works well and is
David De Young
(Extracted from NOAO Newsletter No. 39, 1 September 1994)
The recent KPNO user survey included several questions about the
telescope time allocation process. Responses to this section of the
survey revealed, in some cases, significant misunderstandings about
some aspects of the TAC process. This article is an attempt to clarify
Some respondents believed that the TACs are composed largely of
KPNO scientific staff members. In fact the opposite is the case. Each
TAC has only one member from the KPNO staff; the remaining
members are all from outside institutions. Although the TAC Chair is
filled by a KPNO staff member, the Chair is a non-voting position, and
the Chair does not take part in the discussion of the proposals. The
term of membership for all voting members is now 5 semesters, with
only a minority of the membership changing at any one time in order
to retain a "corporate memory" on the committee. Members are
chosen primarily on the basis of their scientific expertise, but some
familiarity with the KPNO facilities is also desirable. Nominations for
replacement members are solicited from the TAC, members of the
general astronomical community, and NOAO scientific staff.
Candidates are selected by the TAC Chair in consultation with the
NOAO and KPNO Directors. Considerable effort is made to balance
the committee expertise in stellar, galactic and extragalactic astronomy.
Planetary and solar system proposals are sent to two external referees
as well as being reviewed by the committee.
It is important to note that every proposal for every telescope is
discussed in the TAC meetings. Before the TAC meetings grades are
obtained from each TAC member for every proposal to be considered
by that TAC. TAC members are then given the average initial grades
for each proposal, but they are not given the individual grades
submitted by other committee members. After each proposal is
discussed, the committee is asked if any member wishes to change her
or his grade in light of the discussion. If this occurs, a new average
grade is calculated in real time for subsequent use. Because the 4-m
and 2.1-m telescopes are the most heavily oversubscribed, every
proposal for these telescopes is assigned a "lead reviewer". This
person is a TAC member who is responsible for obtaining added
background material about the proposal and who is charged with
leading the discussion of the proposal during the meeting. The lead
reviewer process not only provides focus and direction for the
discussion; it also helps ensure that all the relevant issues concerning
the proposal will be brought forward.
It is likely that this process will be used for the WIYN telescope as
well. After the proposals for a given telescope are discussed and any
regrading is done, the TAC is then asked to recommend the number of
nights a proposal should be given if it can be scheduled. This number
is a recommendation only, and it may be modified as the schedule for
that telescope is developed.
Areas of Concern
Historically, the TAC has focussed on a few major areas of concern,
virtually independent of changes in committee membership. The first
and foremost of these is, of course, scientific merit. Because the
committee is rather small and must cover a wide range of astrophysical
expertise, it is essential that proposals make very clear just what
scientific questions will be addressed by the proposed observations.
The committee often wishes to see these goals placed in a larger
context; i.e., how these questions relate to major unresolved
astrophysical questions. Vague generalities such as "increasing our
understanding" are not sufficient; the committee looks for specific
questions that will be unambiguously addressed by the observations.
Another issue of concern is the description of a clear path from the
taking of the data through the reduction and analysis that will permit
answers to be obtained. Other questions that often arise are whether or
not similar programs have been done or are being done elsewhere, and
if previous observing programs have resulted in the data being
published in a timely manner.
Conflicts of Interest
This is an extremely important and delicate issue, and great care is
exercised to make the TAC discussions as fair and impartial as
possible. Lead reviewers are not given proposals where any PI or Co-I
is located at their home institution. TAC members are not permitted to
grade proposals from their home institution or from any of their
collaborators (and, obviously from themselves). TAC members are
asked to leave the room during discussion of their proposals and
proposals of their collaborators. These procedures are also followed if
any TAC member has any other conflict of interest for any reason.
We hope this description will help clarify the TAC process. The TAC
procedures are continually being scrutinized and modified in an effort
to provide the best system we can devise. We welcome any comments
and suggestions you may have concerning the KPNO telescope time
David De Young