A Canadian Modest Aperture Telescope
Melvin Blake, David Dunlap Observatory
Ovidiu Vaduvescu and Robin Fingerhut, Department of Physics and Astronomy, York University
The Optical-Infrared Astronomy Committee (OIRAC) recently conducted
a series of surveys to determine the needs of the optical infrared community
for future facilities. The surprising outcome of the surveys was a large
number of responses expressing a desire to see more modest aperture telescopes
become available for use by Canadian astronomers. It is encouraging to
find that the Canadian astronomical community is not singularly of the
mind that progress toward exciting new science is taken to be synonymous
with bigger, larger new facilities. While it is obviously necessary to
invest in new large-scale facilities in order to maintain an international
presence, it is economically prudent of us to not lose sight of the fact
that leading-edge science can still be conducted with smaller-scale facilities.
Here we outline just some of the science that would be possible with such
a facility and we justify the economic viability of its construction, operation
Science With Modest Apertures
In the age of 8-10m telescopes and the technological achievements that
have facilitated their construction, it is easy to forget that a modest
aperture telescope can often not only compete with larger telescopes, but
can also make it economically feasible to obtain invaluable supporting
data to augment observations from larger telescopes. The NOAO Newsletter
for March 1997 identifies the following strengths of smaller optical and
Here we include some examples of the sort of science that might be pursued,
which is certainly not complete and is of course subject to our own research
interests and biases.
Support for observations at other wavelengths - radio and from space.
Support for observations made with larger ground based facilities.
Support for survey projects.
Support for observations over long timescales.
Support for coordinated observations by a number of telescopes.
A resource for Astronomy education, including undergraduate programs, public
outreach programs, and student theses research.
A resource for Astronomy faculty in small programs to assist them in conducting
Variable stars of all types are important for understanding many astronomical
problems, from those related to the structure and evolution of stars in
our own Galaxy, to the distances to other galaxies. A 1-2m telescope is
capable of studying such objects to a V-band magnitude of about
21 mag, which would allow studies of variables in globular and open clusters
in addition to variables in Local Group galaxies.
One key project for a modest aperture telescope might be to perform
a study of the structure of the Galactic disk. If equipped with
IR capability, one could observe through the dust in the Galaxy to study
the variable stars in its disk. With good periods for such stars as RR
Lyr stars, Delta Scuti stars, and binary stars, one could obtain a three-dimensional
map of the stellar disk of the Galaxy including the warp in the stellar
disk, which so far is not well studied.
A 1-2m class telescope equipped with both optical and near infrared
capability (NIR) would be a powerful tool in studying nearby
planetary systems. The telescope could be used to take advantage of the
change in the degree of limb-darkening between the optical and NIR to
distinguish between planetary transits and partial eclipses in
binary star systems. The limb-darkening in the NIR can be essentially
neglected. As a result, observations of a shallow eclipse of a binary
star system would be very different in the optical and NIR. The optical
observations would show an eclipse light curve resulting from
two limb-darkened disks passing in front of one another, while that same eclipse in the NIR would show
a light curve of the eclipse of two uniformly illuminated disks.
A planetary transit in the optical shows a light curve of the dark disk of the planet
passing over the limb-darkened atmosphere. A comparison of the
light curves of possible transiting planets in the optical and NIR could
therefore be used to distinguish between true planetary transits and shallow eclipses
in binary star systems. Modest aperture telescopes could be used to search for
nearby planetary systems using these techniques.
SNs, Novae & Transient Targets
A modest aperture telescope would be able to quickly respond to targets
of opportunity such as gamma ray bursts (GRBs), novae and supernovae. In
many cases, early astrometry and photometry of such objects is vital to obtaining
more detailed observations at other sites. This is particularly important
for GRBs, which are visible in the sky for very short periods of time and
therefore require extremely quick response.
Near Earth Asteroids (NEAs)
An impact with an asteroid 0.1-1km in diameter could produce major
global consequences that could happen in the scale of hundreds of
years. Also, an impact with a 10-100m asteroid could
produce local or continental consequences and could happen in the
scale of dozens of years.
As of March 2003, JPL's NEO Program (
includes about 400 known PHAs (Potentially Hazardous Asteroids) and more
than 2000 NEAs (Near Earth Asteroids) from more than 200,000 asteroids
cataloged today by IAU/IMC. These numbers are rapidly increasing with time,
making the potential danger due to the unknown bodies even larger. The recent
close encounter of 2001
YB5 (300m diameter) or the expected one with 1999 AN10 in 2027 are just a
few examples of near encounters. A 1m telescope would be able to track,
recover and discover PHAs and NEAs, and such an effort would be a major
contribution by the Canadian astronomical community to Solar System
research. In fact, all major programs dedicated to this cause use telescopes
between 0.4-1m in a dark site (
Table 1). Therefore, a 1m facility would be perfectly feasible for providing
positional information, which is essential for improving the orbits, and
photometry, which is required to gain physical information. Such a facility
can also be used in nearly real time to recover new objects
http://cfa-www.harvard.edu/iau/NEO/ToConfirm.html) or discover new objects.
Moreover, such a program should get funded easily, due not only to its major
impact for astronomy, but also for the noble aim of guarding the survival of
the human race.
Monitoring of Active Galactic Nuclei (AGNs)
Active galaxies are known to vary on all timescales, but long-term monitoring
is required in order to understand the activity near the centers of such
objects. Larger facilities often cannot commit to long-term (decades) studies,
but smaller facilities can fill the void in this research. The CFHT Legacy
Survey will likely identify many new AGNs, but the priority of the Survey
is to monitor the supernova fields for the lifetime of the project. A small
telescope could continue to monitor the AGNs to expand the timeline of
the CFHT observations.
Despite recent progress in extragalactic studies using 4-10m class
telescopes as well observations from space, many mysteries remain to be
solved about galaxy formation and evolution, from our own extragalactic
neighbourhood to distant clusters. To observe extended sources, a Canadian
1-2m facility equipped with relatively large FOV/instruments (optical and
NIR) in a dark site would have two advantages over a shared larger facility.
First, statistical studies are more feasible on a small facility versus a
shared larger one, where there is a low likelihood of being granted
time-consuming proposals, making it difficult to accommodate a large number
of targets. Second, greater access to a 2m class facility would allow for
deeper observations while still covering a large number of targets.
Training of Astronomy Students
Most of the large new facilities will operate almost exclusively using
service observing. This is required in order to maximize the scientific
return for the considerable financial commitment needed to construct large
telescopes. However, the drawback is that the hands-on experience of the
next generation of young astronomers may be limited to university facilities.
For the majority of universities in Canada, these facilities often lack
the resources for proper maintenance and are located at poor sites, making
it difficult for students to obtain high-quality results and can result
in an uninspiring academic experience. A high quality national telescope
of modest aperture could help address the lack of practical observing opportunities
for both undergraduate and graduate students. A 1-2m class telescope would
provide students with the experience of having to make real-time decisions
related to optimizing their scientific return during their observing run.
One possible educational program for a modest aperture telescope would
be an internship program for graduate students and postdocs in which the
intern would reside at the facility and be responsible for supervising
and conducting service observing for other astronomers. Such a program
would not only train students for service observing, but would also expose
them to the observational requirements of research outside their own specialty.
In addition, the intern would correspond with astronomers in the international
community, enabling them to forge contacts. Student training is an important
consideration when planning the future of astronomy in Canada, and a modest
aperture telescope could play a major part in fulfilling this need.
Cost of a Small Facility
We have obtained the following current cost estimates for the telescope, dome and building
from DFM Engineering. The exact costs for a facility depend strongly
upon the aperture and instrumentation desired, but these may be taken
as good estimate for the construction of a new facility. Estimates here are
given in U.S. funds. For a 1.3m f/4
Cassegrain telescope with a 1.7 degree field, the approximate costs are
$1.2 million for the telescope, $85 000 for the dome and $60 000 for a minimal building.
Mirror handling equipment (without aluminising chamber) is included in these costs.
Detectors make up the majority of the costs; a mosaic camera would cost about
$3 million while a spectrograph would cost several million dollars. The total capital cost would
therefore be roughly $4.2 million U.S., plus $250 000/yr for upkeep. A
2.0m telescope would cost $3 million, and the dome would cost $85 000.
How to proceed?
We must first establish a working group of astronomers interested in obtaining
a modest aperture facility for Canadian astronomers. We would be happy
to hear from all those interested. Since the idea is to provide a facility that is of value to as many
Canadian astronomers as possible, we must first decide on: (1) the telescope
aperture and instrumentation that would be most effective at meeting our
modest-aperture needs; (2) a high-quality as well as accessible site; and
(3) a workable budget. Many questions remain to be
answered, and we will be recording all discussions so that the process
Several possibilities present themselves. We may pursue funding for
the construction of a new modest aperture telescope facility. One idea
is for a Canadian Arctic Observatory (
The option also exists for the construction of two or more modest aperture
telescopes of different sizes or equipped with different instruments, possibly
providing access to both the northern and southern hemisphere skies as
a 'Mini-Gemini' operation.
Another possibility is to pursue re-commissioning of one of the many
modest aperture telescopes that have been phased out at major observatories.
This may be a way of gaining access to a telescope quickly, particularly
if there is a telescope about to be decommissioned which we can immediately
purchase. A situation similar to the University of Toronto Southern Observatory
might be negotiated whereby we obtain the telescope for free and take over
the operating costs in exchange for providing a fraction of time to the
former owner of the telescope. One candidate for such an approach is the
1.0m telescope at La Palma, which is to be decommissioned to free up money
for participation in ESO. A final possibility is to find an international
partner and share a new 1-2m class telescope.
To conclude, we urge the enterprising minds of Canadian astronomers
to consider the value that a modest aperture telescope would add to their
own research as well as to their respective educational programs. We invite
all those interested in this project to contact us at the following address: