on... Site Testing
For a telescope as ambitious as TMT, a great site has to be selected.
The data we are collecting on the astronomy performance of our
candidate sites is now good enough that we are learning a great
deal from it. An internal quarterly review of site testing data,
just conducted, now shows how good our five candidate sites are.
They are all remarkably good, but they are different in significant
Choosing a site for TMT is actually quite complex. We are learning
this as we analyze the data. You might guess that you can specify
in advance how to use the site testing data to rank the sites.
It is not so simple. There are several qualities related to astronomy
observing, and some sites are excellent in some, and offer less
in others. The challenge is to choose a site that will facilitate
all of the kinds of science observations that TMT can perform over
Corner: Our Owners Meet
A great telescope captures the public mind. When I travel and
meet a stranger on an airplane and tell them what I am working
on, the almost invariable reaction is fascination. To look into
the farthest and oldest reaches of the Universe, to spy on the
birth and death of stars, to uncover a hint of a planet around
a distant sun, is high romance and wonder. And to design and build
the giant instrument that makes this possible is an adventure in
Telescopes have been built by private initiative. They have also
been built by public funding. These initiatives have been stimulated
by high public interest and wonder. The public owns the telescope
through its excitement. A great telescope is a public trust.
Nugget—Charting Cosmic Reionization
reionization of the intergalactic medium about 13 billion years
ago was a landmark event in cosmic history. It brought the so-called “Dark Ages” to
a close and rendered space transparent to ultraviolet photons.
Essentially, it marks the beginning of the Universe that appears
familiar to us today.
When did this remarkable event happen? What role did the first
star-forming galaxies play and how did those early systems develop
to become the galaxies we see at later times? These questions represent
the final frontier in understanding the origin of stellar systems
where current facilities are finding it very hard to make further
TMT is just one of several future astronomy facilities that promise
to enable great discoveries at early cosmic times. The successor
to Hubble, the James Webb Space Telescope (JWST), is designed to
image to unprecedented flux limits, and a variety of radio facilities
will chart the spatial distribution of neutral hydrogen using the
redshifted 21-centimeter line. How will TMT interface with such
facilities and what will be its unique role?
Nugget—SODAR: TMT’s Bat in the Night
It’s dark. Too dark to see. And yet as it flies through
the night hunting for its first prey, a bat makes no mistake and
dives with opened jaw right into an unsuspecting moth. If you take
a close look at a bat, it is obvious that the animal does not rely
on its tiny eyes to see in the dark. In some species, the eyes
are even hard to find. What you won’t have problems finding,
however, are its ears. Sometimes several time the size of its head,
a bat’s ears are clearly its main navigation system. As it
flies, a bat emits ultrasounds that reflect off solid surfaces
like trees or insects. Listening to sound reflections, the bat
can build a map of its surrounding without using its eyes.
This amazing technique led to one of the best examples of science
borrowing from nature. In 1906, Lewis Nixon used it to detect icebergs.
Like a bat in the night, it is not possible to see very far through
water and so the SONAR was born. This term, meaning SOund NAvigation
and Ranging, was first coined during World War II when SONARs were
the only way to detect submarines.
with Jerry Nelson
Astronomer Jerry Nelson of the University of California Observatories/Lick
Observatory at UC Santa Cruz is the Project Scientist for the Thirty
brings great experience as the principal designer and project
scientist for the world’s largest optical telescopes, the
twin W. M. Keck telescopes on Mauna Kea, Hawaii, to his job with
TMT, including recent work on Keck’s state-of-the-art adaptive
Jerry received his B.S. in physics from the California Institute
of Technology and his Ph.D. in elementary particle physics from
UC Berkeley. He has earned numerous honors for his work on the
Keck Telescopes. Jerry spoke recently with Warren Skidmore about
the challenges and opportunities of the TMT project.
Download Jerry Nelson interview
[26 min. 24 MB MP3]
Around the Community
European Southern Observatory (ESO) has taken an important step
toward the realization of a new giant telescope for Europe’s
astronomers by creating the ESO Extremely Large Telescope (ELT)
Project Office, headed by Jason Spyromilio, the former director
of La Silla Paranal Observatory.
"We believe that the European Extremely Large Telescope
(E-ELT) is essential if we are to ensure the continued competitiveness
of the astronomical community in ESO’s member-states," said
ESO Director General Catherine Cesarsky, in a July 20 press release.
"This goal can be achieved in a timely manner through ESO and the
community working closely together, and the establishment of the
ELT project office is a significant step in this direction."
The ESO ELT Project Office, part of the ESO Telescope Systems
Division, will work closely with experts from both ESO and the
European scientific community via an ELT science and engineering
working group, and a standing review committee established by the
ESO Council, as well as with other ELT projects, including regular
consultation with the TMT project.
A baseline design for the E-ELT is scheduled to be presented to
the ESO Council at the end of 2006, based on a telescope with a
primary mirror between 30-60 meters in diameter and a financial
envelope of about 750 million Euros.
TMT "In The News"
Recent articles mentioning TMT in the popular media:
the TMT Newscast