Dear all,
First of all, allow
me to wish you a very happy new year
if I haven't already
done so. Let us hope it will bring many new
exciting projects and
ideas into being.
In the middle of
November, Greg and Fred had a discussion of
meeting up with Pierre
Lena to talk about the OHANA (Optical High
Angular Network for
Astronomy) project [for reference, Mariotti et al,
1996, A&AS, 116,
381]. The purpose of this email is to see if we could
organize a first informal
meeting with all the concerned parties
during mid-february,
here in Hawaii, to discuss the linking several
large telescopes on
top of Mauna Kea with optical fibers. Such a
meeting would serve
two main purposes: the first one would be to
determine interests
and motivations within the Mauna Kea community,
and the second one would
be to clearly define the scientific aims and
capabilities of a kilometric
infrared interferometer with 4 to 10
meter telescopes.
The first point
pertains to the fact that, based on IOTA/FLUOR
experience (45 cm telescopes,
no adaptive optics, aging fibers - Guy,
please correct me if
I'm wrong), the limiting magnitude is on the
order of K=5. Simply
taking the aperture area ratio gains 4.5 to 6
magnitudes for 3.6 to
8 meter telescopes respectively. However, there
is one large unknown,
and that is the fiber coupling efficiency. This
is largely a function
of the adaptive optics system and the Strehl
ratio. All three systems,
(Hokupa'a, Keck AO and PUEO deliver Strehl
ratios that should ensure
high efficiencies in K band, but the final
limiting magnitude of
such an interferometer will depend on this
number. A first proposal
would therefore be to bring a fiber to the AO
corrected focus of each
one of the telescopes and measure the coupling
efficiency. The more
long term issue of delay lines would also need to
be touched upon, and
this will depend on interest.
The second point
depends on the first one (i.e. the limiting
magnitude), but is also
much more general: What science could uniquely
be done with large collecting
areas and kilometric baselines? After a
brief discussion with
Guy Perrin, we came to the conclusion that there
are some classes of
objects which may not be in the limelight (such as
aextra-solar planets
- which Keck and VLTI will be able to do much
better), where an instrument
such as OHANA could produce signifiacnt
discoveries. For example,
Ultra-Luminous Infrared Galaxies have K
magnitudes of the order
of 9 (Markarian 231), and which are completely
unresolved at the scale
of 40 mas. Current thoeries suggest that these
are either dust enshrouded
quasars in formation or so-called
"super-starbursts";
whatever the case may be, these objects are unique
in the sense that they
probe the relationship between active nuclei,
quasars and star formation.
More generally
the case of the BLR in AGNs or the structure of
quasars would be difficult
to get to with interferometers such as
CHARA, VLTI, or the
Keck outriggers, which have about 200 meters of
baseline, but with 1.5
to 1.8 meter telescopes. Defining science goals
would help to focus
the direction of the instrument and the
communities we could
depend on (for instance the Keck/Caltech
community has very strong
extragalactic interests) for support and
guidance.
We would therefore
like to propose a date in the first half
of February (but are
open to any suggestions). Please reply to Guy
Perrin, and/or myself,
so we can see how to coordinate such a meeting.
Again, very best wishes for the year 2000,
Olivier
Dear Mauna Kea Ohana
As expected, finding
a date that would staisfy everybody of such
a large and diverse
group turns out to be a difficult task.
After discussion
with various groups, February seems to be ruled
out, and we have to
start looking for a new date for this first meeting
to discuss the OHANA
project. Pierre Lena, and Guy Perrin suggested
sometimes during the
week of Match 13th to 18th; an added advantage of
these dates is that
Steve Ridgeway will be in Hawaii at that period, and
with his excellent expertise
in the field, he could provide some
guidance. (on second
thought, the fact that Steve is in Hawaii also
suggests that there
probably is a Keck interferometry meeting at
the same period...?).
Please let us know
soon what your availabilities are so that we
can try to set a definite
date.
Aloha,
Olivier
Dear Mauna Kea Ohana,
After receiving
positive responses from everyone, we are
converging towards the
dates of thursday march 16th and friday march
17th. We feel that two
days are necessary to effectively cover (or at
least touch upon) most
aspects of this ambitious projects. Of course as
the agenda of the meeting
becomes clearer, some of you who may choose to
attend only the parts
that interest you particularly.
A preliminary agenda
(as passed to me by Guy Perrin might look
as follows:
1. General description
of the project
- Instrumental
expertise and experience
- Astrophysical
niche, goals and aims
2. Consideration of
the main difficulties::
- Delay line(s)
- Beam transport
- Telescope time
and availabilty
3. General discussion
4. Summit tour, with
an estimation of interface work to be made
5. Strategic plan
Of course your input
is highly valued and these are
suggestions. However,
at such an early stage, we can really look in
depth at two aspects:
1/ the astrophysical domain that we can tackle and
that is delimited by
the following observationnal parameters: a limiting
K magnitude around 9
or 10 and a resolution of the order of 3 mas
(GEMINI-CFHT) and 0.5
mas (GEMINI/CFHT-KECK). 2/ The basic instrumental
setup, and the crucial
fiber injection coefficient, which will pinpoint
the limiting magnitude.
Aloha,
Olivier
Dear Ohana,
Here is an outline
of a possible agenda that we are
suggesting. Please let
me know if you are willing to give a little talk
(or at least direct
the discussion) on the subject allocated to you. Of
course, we are leaving
plenty of time for discussion so that you do not
have to fill the allocated
time.
Looking forward to seeing
all of you,
Olivier
NB. Thursday afternoon
will be the site visit for those who want. We
hope to be able to see
the environment in which the fiber injection will
take place on each telescope.
Please let us know if you wish to
participate.
Thursday 16th:
9:00- 9:05 Welcome
- Greg Fahlman
9:05- 9:40 Introductory
Remarks, discussion of Scope - Pierre Lena
9:40-10:15 Introduction
to fiber interferometry - Guy Perrin
Coffe break
10:30-10:45 Keck AO/Interferometry
update - Peter Wizinowich/Fred Chaffee
10:45-11:00 Gemini AO
update - Francois Rigaut/Matt Mountain
11:00-11:15 CFHT AO
update - Olivier Lai
11:15-11:30 UH Interferometry
and AO update - Francois Roddier
12:00-17:00 Summit visit
Friday 17th
9:00- 9:30 description
of project (instrumental) Guy Perrin/Pierre Lena
9:30-10:00 description
of project (astrophysical) Steve Ridgway/Olivier Lai
10:00-10:15 Coffee Break
10:15-10:30 Innovative
solutions (wide field? - Guy Perrin, Delay lines -
Malcom Northcott)
10:30-12:00 description
and discussion of difficulties (delay lines,
beam transport,
telescope time)
12:00-13:00 Lunch
13:00-16:00 Open discussion
16:00-16:45 Choice of
strategy
16:45-17:00 Closing
remarks - Pierre Lena
Dear OHANA,
In preparation
for tomorrow's meeting, and after discussion
with Pierre and Guy,
here is a new, revised agenda, that should help us
to get to the crucial
points in a more structured way. Please let us
know if you have objections
or suggestions. After the agenda, I am
also including detailed
logistics about tomorrow's summit visit. Please
let me know if you have
a change of plan.
Olivier
OHANA Meeting Agenda:
Thursday, March 16th
--------------------
9:00- 9:05 Welcome
- Greg Fahlman
9:05- 9:25 Introductory
remarks, discussion of scope - Pierre Lena
9:25- 9:45 Introduction
to fiber interferometry - Guy Perrin
9:45-10:30 Discussion
& Questions (with Coffee)
10:30-10:45 Keck AO/Interferometry
update - Peter Wizinowich
10:45-11:00 Gemini AO
update - Francois Rigaut/Matt Mountain
11:00-11:15 CFHT AO
update - Olivier Lai
11:15-11:30 UH interferometry/AO
update - Francois Roddier/Olivier Guyon
11:30-12:00 First exchange of views.
12:00-17:00 Summit visit.
12:00-13:00 Drive to
HP
13:00-13:30 Acclimatize,
packed lunch.
13:30-14:00 Drive to
summit
14:00-15:00 Keck visit
15:00-16:00 Gemini visit
16:00-17:00 CFHT visit
Friday, March 17th
------------------
9:00- 9:15 Science
goals and possibilities - Steve Ridgway
9:15- 9:30 Extragalactic
astronomy with OHANA - Olivier Lai
9:30- 9:45 A double
demonstration (short term science goals) Guy Perrin
9:45-10:00 Discussion
10:00-10:30 Injection
AO/fiber coupling
Coffee
10:45-11:15 Transport
and delay lines
11:15-11:45 Recombination
and operating modes
Lunch
13:00-16:00 Open discussion
(Chairman: Steve Ridgway)
- Exrpession
of interest
- Technical issues
- Possible sharing
of tasks
- Budgetary and
manpower issues
- Telescope time
- Schedule
16:00-16:30 Summary
and conclusions
16:30-16:45 Closing
remarks - Pierre Lena
Logistics for Summit
visit:
---------------------------
[...]
Dear CFHT Ohana,
As some of you
may remember, during the Board of Directors, we
heard the concerns of
a Kahuna concerning the summit of Mauna Kea. At
one point, he mentionned
that we should consider linking up all the
telescope on the summit
in one big telescope, as all these teelscopes
form a community, a
family, he actually used the word Ohana. This is
uncanny, because in
the astronomical litterature, we find a description
of a project called
OHANA, (Optical High Angular Network in Astronomy,
By Jean-Marie Mariotti,
1996, A&AS, 116,381) which is exactly that!
Linking up the large
telescopes on Mauna Kea with optical fibers to make
one giant telescope.
Without getting
into too much details, this technique allows to
link up different telescopes
into one such as the Keck Interferometer,
or the VLTI, in Chile.
What it does is to provide the *resolution* of a
telescope that is as
large as the distance between the two indivdual
telescopes, without
having the light collecting area. So for instance by
linking up CFHT and
Gemini, we would be able to see details as small as
what an 800 (!!!) meter
telescope would see, but we would be limited in
brightness to objects
that we can already see now with those
telescopes (and that's
already pretty faint...).
Today and tomorrow,
we are hosting the kick-off meeting for such
a project. Our guests
are from Keck, Gemini, and UH and Paris
Observatory. All familiar
faces, I'm sure, as they all are friends and
neighbours in town and
at the summit. We will try to have as little
impact on operations
as possible, but we have a summit visit planned
this afternoon. We should
come by CFHT at around 4:00 pm.
I just wanted to
let you know about this so that if you meet
some of our larger OHANA,
in a corridor or around the telescope, you can
extend your feelings
of aloha to them.
Olivier
Chere Therese,
comme je l'avais annonce
lors de la journee de prospective HRA du
laboratoire en septembre
dernier, Olivier Lai et moi faisons une
proposition d'Action
Thematique Innovante a l'INSU dont le theme est le
grand interferometre
a fibres du Mauna Kea (suite a l'article Mariotti et
al. de 1996).
En raison du montant
limite attribuable, nous avons cible notre demande sur
la demonstration de
l'injection dans une fibre monomode au foyer du CFHT et
de GEMINI, le but etant
d'etablir la sensibilite du futur interferometre et
de montrer que l'on
peut atteindre les objectifs scientifiques que nous
nous fixons, a savoir
les sources extragalactiques compactes inaccessibles
aux resolutions du Keck
et du VLTI. Cette demonstration sera la base d'un
futur instrument et
les platines d'interface/injection en seront les
premiers maillons.
Suivant les instructions
de l'INSU, notre proposition doit etre envoyee par
mail (la solution la
plus rapide compte-tenu des echeances et de notre
eloignement geographique
actuel). Elle devra etre precedee par une lettre
de validation de votre
part (je suppose qu'une copie e-mail doit etre
acceptable).
Pourriez-vous, si vous
jugez notre proposition valide, nous donner votre
accord (avant lundi)
et faire parvenir a l'INSU votre lettre de validation
(adresse electronique
: ati.insu@cnrs-dir.fr).
Olivier et moi sommes
desoles pour ce bref pre-avis. Cette periode est
extremement chargee
et nous avons fait notre maximum pour pouvoir soumettre
une proposition a temps.
Je me rends la semaine prochaine a Hawai, apres
les observations FLUOR/TISIS,
en compagnie de Pierre Lena, a une reunion
organisee par Olivier
pour discuter du projet global avec des representants
de l'Universite d'Hawai,
du TCFH, du Keck et de Gemini. L'echo semble etre
tres positif la-bas
et il se peut que les choses demarrent rapidement.
Tres respectueusement,
Guy.
Guy Perrin
Département de
Recherche Spatiale
Observatoire de Paris,
section de Meudon
5, place Jules Janssen
F-92190 FRANCE
Tel : +33 1 45 07 79
63
Fax : +33 1 45 07 71
02
From: Therese
Encrenaz <Therese.Encrenaz@obspm.fr>
Subject: soutien
a la demande ATI Lai-Perrin
Date: Fri, 10
Mar 2000 15:27:42 -0700
Chere Genevieve,
Je te confirme par ce
mail que j'apporte tout mon soutien a la demande
d'ATI presentee par
O. Lai et G. Perrin
"Recombinaison interferometrique
des grands telescopes du site de Mauna Kea
a Hawaii".
Bien amicalement,
Therese
Mesdames, Messieurs,
nous vous prions de trouver
ci-joint notre proposition d'action thematique
innovante pour 2000
intitulee :"Recombinaison interferometrique des grands
telescopes du site du
Mauna Kea a Hawai".
Cette proposition beneficie
du soutien de nos directeurs respectifs de
laboratoire (Greg Fahlman/TCFH,
Therese Encrenaz/DESPA/Observatoire de
Paris) exprime par e-mail
par Therese Encrenaz voici quelques jours.
Vous souhaitant bonne
reception, nous nous tenons a votre entiere
disposition pour vous
apporter tout eclaircissement qui vous paraitrait
necessaire.
Olivier Lai
(lai@cfht.hawaii.edu)
Guy Perrin
(guy.perrin@obspm.fr)
Guy Perrin
Département de
Recherche Spatiale
Observatoire de Paris,
section de Meudon
5, place Jules Janssen
F-92190 FRANCE
Tel : +33 1 45 07 79
63
Fax : +33 1 45 07 71
02
In parallel, Greg Fahlman met with Professor Hiroyasu Ando, director of Subaru to discuss the idea.
We look forward to welcoming Subaru into our OHANA.
I do think this is an
important project to move the IRTF into, and
it is certainly consistent
with NASA's intellectual interests in
interferometry. Indeed,
this could be another important argument to
support the IRTF.
 |
Olivier Lai (Chairman) | CFHT |
|
Jun Nishikawa | Subaru |
|
Peter Wizinowich | Keck |
|
Steve Ridgway | NOAO |
|
Alan Tokunaga | IRTF |
|
Francois Rigaut | Gemini |
|
Andy Adamson | UKIRT |
|
Pierre Lena | DESPA (Obs Paris) |
|
Guy Perrin | DESPA (Obs. Paris) |
A distribution list (probably with an email such
as ohana@cfht.hawaii.edu) is currently being set up. We intend to use it
for broadcasting information to everyone involved in OHANA. It will be
running with the majordomo program and here is a preliminary list of the
recipients (As soon as it is set up, I will reconfirm with everyone in
this list).
| CFHT | - Greg Fahlman
- Catherine Dougados - Olivier Lai - Francois Menard - Derrick Salmon - Christian Veillet - (other astros?) |
|
| IfA (UH) | - Francois Roddier
- Claude Roddier - Buzz Graves - Olivier Guyon |
- Malcom Northcott |
| NOAO | - Steve Ridgway | |
| DESPA | - Pierre Lena
- Vinecent Coude du Foresto - Guy Perrin - Daniel Rouan - Julien Woillez |
|
| Keck | - Fred Chaffee
- Peter Wizinowich - James Beletic |
|
| Gemini | - Matt Mountain
- Francois Rigaut |
|
| Subaru | - David Saint Jacques | |
| IRTF | - Alan Tokunaga
- Bob Joseph |
|
| Limoges | - Francois Reynaud |