The Messenger No. 168 - June 2017 - European Southern Observatory
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ELT First Stone ceremony
1st and 2nd generation ESO Public Surveys
Cherenkov Telescope Array
Highlights of the VIPERS survey
The Messenger
No. 168 – June 2017
The Organisation DOI: 10.18727/0722-6691/5018
A Long Expected Party — The First Stone Ceremony
for the Extremely Large Telescope
Tim de Zeeuw1
ePOD/J. P. Astorga
Fernando Comerón1
Roberto Tamai1
1
ESO
The ceremony to seal the time capsule,
signalling the beginning of construction
of the dome and main telescope struc-
ture for the Extremely Large Telescope,
took place at the Paranal Observatory
on 26 May 2017, in the presence of the
President of Chile, Michelle Bachelet
and many international guests. Owing
to high winds, the ceremony could not
take place as planned on the levelled
site on Cerro Armazones, but instead
was held at the Paranal Residencia. A
brief report of the event and its organi-
sation is presented, and the welcome cials from the governments of the latter Figure 1. ELT Project Manager Roberto Tamai illus-
trates to President Bachelet the approximate real
speech by the ESO Director General is two countries.
size of each of the nearly 800 segments that will
included. comprise the ELT primary mirror, in front of a model
The significance of the event in the history reproduction of the telescope and enclosure, flanked
of ESO was symbolised by the p resence by the Director of Operations, Andreas Kaufer (left),
and the Director General, Tim de Zeeuw.
Late May is becoming a time for major of the former Directors General Lodewijk
highlights in the history of the Paranal Woltjer, Harry van der Laan and Catherine
Observatory. On 26 May 2017, over two Cesarsky, as well as the Director General tion works. Despite sustained efforts
hundred guests from Europe, Chile and designate Xavier Barcons (see Figure 8). until the last possible minute, under
the rest of the world gathered at the The leaders of major observatories and nearly heroic conditions that involved
Paranal Residencia to celebrate the First astronomy organisations including the crews staying at Armazones overnight
Stone of the Extremely Large Telescope Atacama Large Millimeter/submillimeter waiting for the winds to abate, the day
(ELT), as well as the connection of the Array (ALMA), the Association of Universi- before the event it was decided to revert
Observatory to the Chilean power grid. ties for Research in Astronomy (AURA), to a backup plan already prepared in
This was exactly 19 years and one day the Carnegie Institution for Science, cooperation with the Presidential team
after Antu, the first Unit Telescope of the Gemini, the Giant Magellan Telescope and to host the ceremony at the Paranal
VLT, saw first light, and one year and (GMT), the Large Synoptic Survey Tele- Residencia. This may well have been a
one day after the signature of the largest scope (LSST), the National Radio Astron- blessing in disguise, as the comfortable
contract in the history of ground-based omy Observatory (NRAO), The University environment of the Residencia made
astronomy, for the construction of the of Tokyo Atacama Observatory (TAO) the ceremony much more interactive
dome and main structure of the ELT. and the International Astronomical Union and protected the attendants from the
(IAU) were also present. Managers of hostile conditions on that day at Cerro
The date of the ceremony was carefully companies that are key to the ELT con- Armazones, although at the cost of
chosen to allow the presence of the struction, most notably Astaldi and reducing the obvious symbolism of a
President of Chile, Michelle Bachelet, SAESA, were among the p articipants as ceremony on the summit where the ELT
who had expressed a strong personal well. Correspondents of numerous will rise.
interest in using this opportunity to pay national and international media covered
her first visit to an ESO site. The support the ceremony, which was featured Upon the arrival of President Bachelet
of the Chilean government to ESO’s around the world. and other senior dignitaries, an informal
activities was made very visible by the welcome reception took place at the
attendance of the Ministers of Economy, The ceremony had been planned to take Residencia which gave ample opportunity
Mining and Energy, and of many other place at the top of Cerro Armazones, for interaction among the participants
Chilean authorities. The ambassadors of where the ELT will be located and where and with the President (Figures 1–3). This
12 of the 15 ESO Member States were a large tent was being erected one week included, as planned, the leadership
present, as well as the Council President, ahead of the event. However, in the days of the Paranal Union, who presented the
Patrick Roche, members of the ESO before the event exceptional conditions, President with a small vase containing soil
governing bodies from the Netherlands, with windspeeds much higher than usual, from the five ESO sites in Chile (Vitacura,
France, Spain and Italy, and higher offi- prevented the completion of the prepara- La Silla, APEX, Paranal and Armazones).
2 The Messenger 168 – June 2017
ePOD/J. P. Astorga
ePOD/J. P. Astorga
Figure 2. President Bachelet is shown posing for Figure 3. Paranal Union leaders pose with President
selfies with children from Taltal during the First Stone Bachelet after presenting her with a vase containing
event in the Paranal Residencia. soil samples from the five ESO sites in Chile.
The formal ceremony started at 13:30 which a vision of a large telescope the country. As President Bachelet noted
with the arrival of President Bachelet and advanced a century and a half ago by in her speech, “With the symbolic start
the ESO Director General in the lower Jules Verne was compared with the real- of this construction work, we are building
area of the Residencia, where the attend- ity of the construction of the ELT. His more than a telescope here: it is one
ees were already waiting. A sequence speech was followed by one from Paolo of the greatest expressions of scientific
of introductory videos was shown about Astaldi, President of the leading partner and technological capabilities and of the
the ELT (Figure 4) and the companies in the ACe Consortium that is building the extraordinary potential of international
Astaldi, Cimolai, REOSC and Schott, dome and the main telescope structure. cooperation”.
which have so far signed large ELT con- Next was a speech by the internationally
tracts. Also included was a video pre- renowned astronomer María Teresa Ruiz, The highlight of the ceremony came with
pared by SAESA, the company that has currently President of the Chilean Acad- the filling and sealing of a time capsule
built the extension of the grid to Paranal emy of Sciences. The closing speech which had been manufactured in the
and Armazones. was given by President Michelle Bachelet, Paranal workshop by Patricio Alarcón
who stressed the importance of astron- and his team. The Director General started
A welcome speech (presented on p. 5) omy for the development of Chile and the by depositing a copy of the ELT Science
was given by the Director General, in great significance that the event had for Case as foreseen in 2011. President
Figure 4. (Left) Roberto
ePOD/J. P. Astorga
ESO/F. Comerón
Tamai, Project Manager
of the ELT; Paolo Astaldi,
President of the Astaldi
construction group; Tim
de Zeeuw, ESO Director
General; Michelle
Bachelet, President of
the Republic of Chile;
and María Teresa Ruiz,
President of the Chilean
Academy of Sciences,
watch the opening video
at the ELT First Stone
ceremony.
Figure 5. (Right) The
glass plate donated by
President Michelle
Bachelet to be included
in the time capsule. The
legend in Spanish reads:
“Opening the sky of
Chile to the questions of
a whole planet”.
The Messenger 168 – June 2017 3
The Organisation de Zeeuw T. et al., The First Stone Ceremony for the Extremely Large Telescope
Figure 7. The ESO ELT
ESO/T. de Zeeuw
ESO/M. Cayrel
Team braving the wind
on Cerro Armazones on
the day after the official
c eremony.
Figure 6. The time capsule that was filled during describing what the observatory means Paranal, until the time when progress on
the ELT First Stone ceremony, manufactured at the
for them. The Press Release1 contains the construction of the dome allows it
Paranal mechanical workshop. The cover includes
a 1:5 scale reproduction of a segment of the ELT more details of the event, with photo- to be encased in one of the walls, where
p rimary mirror, made in Zerodur ®. graphs and videos. its cover will be left visible.
Finally the President deposited a pen Following the ceremony many of the
Bachelet followed by depositing a copy made of Chilean copper and the last item guests paid a visit to the VLT telescopes,
of the lavishly illustrated book, “Atacama”, to be added to the time capsule was an which the President was unfortunately
coauthored by ESO staff member Gerd elegant plate of glass, with the sentence unable to join because of another com-
Hüdepohl. Next, the Director General “Opening the sky of Chile to the ques- mitment. In parallel, the extension of the
unrolled two posters with the pictures tions of a whole planet” written in Spanish, Chilean electrical grid, constructed by
and names of staff working at ESO at the from President Bachelet (Figure 5). The SAESA with the support of the Chilean
time, which were held up by the Director time capsule was then closed with a Government, was celebrated and the
General and the President to be shown cover that contains a 1:5 scale reproduc- Armazones power station, that converts
to the audience, then rolled up again and tion of a segment of the ELT primary mir- the voltage from 66kV to 23kV, was inau-
left inside the capsule. At that point, a ror made in Zerodur®, the same material gurated.
group of six school children from the town of which the actual segments will be
of Taltal, in whose grounds Cerro Paranal made by Schott, with the flags of the ESO The First Stone event was also the occa-
is located, were called upon to join the Member States and Chile engraved and sion to introduce the team of the ELT
President and the Director General to a legend commemorating the ephemeris Project Managers to Paranal colleagues.
place in the time capsule their drawings (Figure 6). The capsule is in storage at The agenda of the four-day ELT Team
visit included: the presentation of the ELT
team and updated status to Paranal col-
leagues; exchanges of experience and
lessons learned, and discussions on sub-
jects of mutual interest; an extensive visit
to the telescopes and technical facilities;
and a visit to Armazones (Figure 7). This
contact will facilitate the assembly, inte-
gration and verification of the ELT and its
smooth integration into the operations of
the Paranal Observatory.
Figure 8. Past, present and future Directors General
of ESO at the Paranal Residence. From left to right:
Lodewijk Woltjer (1974–1987); Harry van der Laan
(1988–1992); Catherine Cesarsky (1999–2007); Tim
de Zeeuw (2007–2017); and Xavier Barcons (2017–).
Regrettably, Riccardo Giacconi (1993–1999) could
not attend the ceremony.
4 The Messenger 168 – June 2017
Figure 9. President Bachelet accom-
panied by most of the Paranal logistics
team who played a major role in
organising the ceremony.
The symbolic laying of the ELT First Acknowledgements Jane Wallace, Priya Hein and María Adriana Arrau,
for handling and coordinating the invitations, confir-
Stone coincided with the signature of
The success of the event and all the concurrent mations and transport schedules of many of the
the Armazones site handover to the ACe activities in the same week at the Paranal Obser guests; and to the production company, Macoffice,
Consortium, following resolution of a vatory owes much more than can be described in which took care of the hardware for the ceremony,
number of technical and legal matters. this article to the Paranal logistics team led by including the tent at Armazones whose installation
Christine Desbordes (pictured in Figure 9); to the was ultimately prevented by the wind. ESO is also
From now on, access to Armazones will
Education and Public Outreach Department led by indebted to the Presidential Avanzada team for their
have to be approved by ACe. In the next Lars Christensen and by Laura Ventura in Chile; to invaluable assistance and advice with the prepara-
few months, the on-site construction the many colleagues working at Paranal who agreed tion of the ceremony.
activities will begin giving shape to the to leave the comfort of their rooms at Paranal for a
couple of nights stay in Antofagasta, thus making
gigantic telescope and change the physi-
it possible for many important guests to stay at the Links
ognomy of Armazones forever. All the Observatory on the nights before or after the First
hard work will eventually lead to another, Stone event; to the executive assistants of the Cabi- 1
ress Release on ELT First Stone: http://www.eso.
P
even bigger, celebration; the First Light of net and the Representation in Chile, Isolde Kreutle, org/public/news/eso1716
the ELT in 2024.
Text of Speech
Welcome It is unfortunate that the unusually inclement in Colorado, in order to be able to see the
weather prevents access to the platform on capsule orbiting the Moon. Verne calculated
Cerro Armazones, so we gather here in the that this needed a telescope with a main
Tim de Zeeuw, ESO Paranal Residence instead. mirror of 4.8 metres diameter, which was fully
two and a half times larger than that of the
Let me start by taking you back about largest telescope at the time, Lord Rosse’s
President Bachelet, Ambassadors, Ministers 150 years. In 1865, Jules Verne published a Leviathan of Parsonstown, Ireland. A bold
Céspedes, Rebolledo and Williams, Members famous book entitled “The Journey to the step! Verne mentions that the telescope tube
of the Congress, Senator Giannini, State Moon”. It turned out to be uncannily prophetic, was 84 metres long and that the entire system
Secretaries, Council President, Council dele- describing an Apollo-sized capsule with three was built in a single year. The site had of
gates, Mr. Astaldi, Messrs Sammartano, persons on board, launched by a monster course to be in the United States for reasons
Marchiori, Diaz and Alliende, former Directors cannon located near Tampa in Florida, very of national pride.
General Woltjer, van der Laan and Cesarsky, close to Cape Canaveral. All at the initiative of
Director General designate Barcons, other an American gun club, with a key role for, yes, It took a century before Borman, Lovell and
distinguished guests, colleagues and friends, a French scientist. Anders orbited the Moon in Apollo 8 in
it is a pleasure to welcome you on this historic December 1968. It took another eighty years
occasion. It is probably less well known that the story before Verne’s giant telescope was built, not
also describes the construction of a giant tele- in Colorado but instead on Mount Palomar in
scope at 4300 metres altitude on Longs Peak California, and with an improved design. This
The Messenger 168 – June 2017 5
The Organisation de Zeeuw T., Text of Speech
is the world-famous 200-inch telescope, often The Chilean government carefully protects because of the enormous scientific return and
referred to as the Big Eye, and inaugurated in the quality of the night skies and realises that ESO’s track record in delivering quality. The
1948. the international observatories provide training key authorisation for construction was granted
and employment for many Chileans: telescope in 2014 under Council President Barcons, who
Only 40 years later, technology had already operators, technicians, engineers, astrono- is now the Director General designate.
advanced sufficiently to gain another factor mers and administrative staff. Chilean univer-
of two in mirror diameter, and today a dozen sities have developed internationally competi- Two other giant telescopes are planned,
fully steerable 8–10-metre-class optical tele- tive astronomy programmes, and some have the Giant Magellan Telescope (GMT) on
scopes are in operation, including the world- started engineering programmes for astro- Las Campanas here in Chile, and the Thirty
leading Very Large Telescope (VLT) here on technology, creating capabilities and know- Meter Telescope (TMT) in the northern hemi-
Paranal. It is a distinct pleasure to recognise how that will benefit Chilean society more sphere. Together with the ELT, these tele-
Lo Woltjer, who initiated the VLT project and generally. ESO is proud to be associated with scopes will open a new era of discovery
got it funded and approved, Harry van der Laan this impressive growth of capabilities, which whose implications may well go beyond
who selected Paranal as the site, placed all the is also reflected in the fact that the President astronomy. The cooperation between these
major contracts and designed the successful of the Chilean Academy of Sciences, María three projects to address technological chal-
collaborative model for instrumentation devel- Teresa Ruiz, who will also speak today, is an lenges is yet another example of international
opment, and Catherine Cesarsky who brought internationally acclaimed astronomer. collaboration for the sake of science. I am
the VLT to full operation. Riccardo Giacconi pleased to acknowledge our colleagues from
had a key role during construction and first Almost exactly a year ago, ESO signed the GMT and TMT present here for this joint
light, but could unfortunately not be here today. largest ever contract in ground-based astron- endeavour, as well as for providing the frame-
omy with the ACe consortium, consisting work of a stimulating and healthy competition
Nearly twenty years have passed since first of Astaldi, Cimolai and the nominated sub- from which we all benefit.
light of the Very Large Telescope. ALMA has contractor EIE Group, for the construction of
meanwhile been constructed on Chajnantor the giant dome and the 3000-tonne telescope The size of the primary mirror of the ELT, and
in Chile by an international partnership structure. Today’s event marks the official start the revolutionary telescope design which
and is operational, and telescope technology of the construction of the telescope structure includes built-in adaptive optics to correct for
has advanced again. Today we officially and dome of the ELT. the turbulence in the atmosphere, will make
start construction of the Extremely Large Tele- the ELT the world’s biggest and sharpest eye
scope (ELT). Its dome will have a diameter Today also marks the connection of Paranal on the sky for the foreseeable future. This
of 85 metres and a height of approximately and Armazones to the Chilean electrical grid. giant leap in capability is as large as that
80 metres, so that Verne’s telescope tube The Chilean Government has helped ESO to experienced by Galileo when he first turned
would fit. However, the ELT has a segmented find a solution for the supply of power to the his telescope to the heavens!
main mirror with a diameter of an astounding Observatory, through the Comisión Nacional
39 metres. This is a jump of a factor four to de Energía, la Superintendencia de Electricidad The goal for its use is not that of Verne, to see
five over any existing telescope! The collecting y Combustibles, and the Ministries of National details on the Moon, or the developments
area of the ELT primary mirror is nearly 1000 Assets and Foreign Affairs and our consultants in the Moon Village proposed by the European
square metres, which is larger than that of from MegaRed. The connection to the central Space Agency, or to watch all of Middle Earth,
all 8–10-metre-class telescopes in the world grid in Paposo is managed by Grupo SAESA, but instead to study the deep Universe, to
combined. Jules Verne would have liked it! and I am very pleased that it is represented resolve the light of nearby galaxies into that of
here today. The grid connection will reduce its constituent stars, and above all to image
A revolutionary telescope needs an excellent costs, provide greater reliability and stability, and characterise the rocky planets that we
site, and the choice of Cerro Armazones and will also reduce the Observatory’s carbon now know orbit most stars. It is in fact possible
was the result of a world-wide site selection footprint. that the ELT will find evidence for life on other
process, chaired by Rene Rutten, who is worlds. It is ironic that this would be done from
here today. The Chilean government gener- It has taken 18 years to get to this point, the magnificent desolation of the Atacama
ously extended the land donated to ESO in thanks to the efforts of many people all over Desert.
1995 towards the east, so that it now contains the world, including former Italian delegate
both Paranal and Armazones, and ESO can Nanni Bignami who unfortunately passed The ELT construction effort is carried out by
operate the ELT as part of the Paranal Obser- away very suddenly two days ago. Roberto a large team with staff from across ESO, led
vatory. The first discussions on this topic were Gilmozzi initiated the precursor 100-metre- by Roberto Tamai who works closely with
with President Bachelet during her previous diameter OWL project, Riccardo Giacconi pro- ESO’s top management. Many team members
term. The process was completed under moted it, Catherine Cesarsky oversaw the are here. Roberto will make sure that the con-
President Piñera, with key preparatory work careful process that resulted in the start of a struction will stay on schedule, so that what
done by Ambassador Rodriguez of the Ministry full design study in early 2007 for what was, was once a dream becomes reality.
of Foreign Affairs and by ESO’s previous rep- by then, a single European project, and Jason
resentative Massimo Tarenghi. Since then Spyromilio led the extended design effort, car- The ELT will no doubt produce discoveries
ICAFAL, also represented here, have prepared ried out with industry in the Member States. that we simply cannot imagine today, and it
the giant platform and a new access road, so will surely inspire numerous people around the
that today we take the next step, again with In the years that followed it was possible to world to think about science, technology and
President Bachelet. I am sure that the location convince the 15 ESO Member States to commit our place in the Universe. This will bring great
of the ELT in Chile is a justified source of significant additional funding for the ELT Pro- benefit to the ESO Member States, to Chile,
national pride, just as in Verne’s story. gramme despite the financial crisis. I am very and the rest of the world. For this reason we
grateful for this support, which was provided seal the ELT time capsule today for all mankind.
6 The Messenger 168 – June 2017
Telescopes and Instrumentation
ESO/E. Vernet
The Deformable Secondary Mirror being hoisted
into its hub, already mounted on the top end of
Unit Telescope 4.
Telescopes and Instrumentation DOI: 10.18727/0722-6691/5019
The Adaptive Optics Facility:
Commissioning Progress and Results
Robin Arsenault1 2017 and the GRAAL ground-layer GRound-layer Adaptive optics Assisted
Pierre-Yves Madec1 adaptive optics mode by the end of the by Lasers (GRAAL) in ground layer adap-
Elise Vernet1 year. tive optics (GLAO) mode is planned by
Wolfgang Hackenberg1 the end of 2017. Then only MUSE with
Paolo La Penna1 GALACSI in Narrow Field Mode (NFM)
Jérome Paufique1 Introduction will remain to be commissioned in 2018.
Harald Kuntschner1
Jean-François Pirard1 Towards the end of 2016, the only miss-
Johann Kolb1 ing pieces of the Adaptive Optics Facility Installation of new M2 unit on UT4
Norbert Hubin1 (AOF) complex (see Arsenault et al., 2010,
2014a and 2016 for previous progress In September 2016, the 14 crates con-
updates) were the new secondary mirror taining the DSM system (Arsenault et al.,
1
ESO (M2) unit — the Deformable Secondary 2013a; Manetti et al., 2014; Briguglio et
Mirror (DSM) — and the Ground Atmos- al., 2014), totalling 9 tonnes and 50 cubic
pheric Layer Adaptive optiCs for Spectro- metres, were unpacked in the New Inte-
All the Adaptive Optics Facility (AOF) scopic Imaging (GALACSI) adaptive gration Hall (NIH) in Paranal. The system
subsystems are now in Paranal and optics (AO) module. The new M2 unit was was re-assembled in the NIH and func-
the project team is working on com installed in October 2016 during a shut- tionalities tested. It was an opportunity
missioning activities on Unit Telescope down of Unit Telescope 4 (UT4 — Yepun) to cross-train our Paranal colleagues
4 (UT4) of the Very Large Telescope. and the whole telescope was recommis- and demonstrate several handling opera-
Excellent progress has been made; the sioned with the new M2 unit by December tions, including the critical thin-shell mir-
new secondary mirror unit, the Deform- 2016. Since then, UT4 has returned to ror handling.
able Secondary Mirror (DSM), was operations and the Paranal telescope
installed in October 2016 and UT4 is and instrument operators (TIOs) and sci- Before proceeding with the removal of
now operating routinely with the DSM in ence support staff have been trained to the old Dornier M2 unit, a laser tracker
non-adaptive optics mode. The other use the telescope with this new second- was installed on the telescope centre-
modules of the AOF, the Ground Atmos- ary mirror in non-adaptive optics mode. piece and used to record reference
pheric Layer Adaptive optiCs for Spec- The AOF team remains in close contact positions of markers on the telescope
troscopic Imaging (GALACSI), the with Paranal staff and closely monitors structure and the M2 hub and spiders.
4 Laser Guide Star Facility (4LGSF) and any errors and issues to provide support Additionally, reference measurements
the GRound-layer Adaptive optics and solutions. were taken to characterise the telescope
Assisted by Lasers (GRAAL), have been optical behaviour and performance,
installed and are being qualified. The At the end of 2016, the GALACSI instru- some of them using the GRAAL Mainte-
coupling with the High Acuity Wide ment was dismounted from the Adaptive nance and Commissioning Mode (MCM)
field K-band Imager (HAWK-I) and the Secondary Simulator and InStrument wavefront sensor. Close-out measure-
Multi Unit Spectroscopic Explorer Testbed (ASSIST) in the Garching integra- ments were also taken for the instru-
(MUSE) has been tested and all ele- tion hall and packed for transport to ments available at UT4 (the Spectrograph
ments are functional and ready to pro- Chile. After reintegration in Paranal, all for INtegral Field Observations in the
ceed with their full commissioning. functionalities were recovered. In late Near Infrared [SINFONI], HAWK-I, MUSE
The goal for the AOF is to complete March 2017, GALACSI was installed on and the VLT Interferometer [VLTI]) with
GALACSI wide-field mode technical UT4 and was then ready to enter the the support of Science Operation. These
commissioning by the end of summer commissioning phase. would later be used to verify that tele-
scope and instrument performance had
The project is now fully involved in not been degraded after the installation
ESO Project Team:
commissioning activities and these will of the new M2 unit.
D. Bonaccini Calia, P. Duhoux, J.-L. Lizon, S. Guisard, continue during 2017 and into part of
P. Lilley, L. Petazzi, P. Hammersley, I. Guidolin, 2018. Commissioning runs are scheduled On 14 October 2016, the first transport
L. Kern, T. Pfrommer, C. Dupuy, R. Guzman, J. almost every month during bright time. took place to UT4 and the DSM hub
Quentin, M. Quattri, R. Hozlöhner, D. Popovic, M.
Comin, S. McClay, S. Lewis, F. Gago, M. Sarazin,
Some of them may be returned to science was brought to the telescope. The next
P. Haguenauer, A. Jost, J. Argomedo, S. Tordo, operations if commissioning progress is day the DSM followed the same route.
R. Donaldson, R. Conzelmann, M. Lelouarn, rapid and if there are no technical prob- Extreme care was taken during the trans-
R. Siebenmorgen, M. Downing, J. Reyes, M. Suarez lems or bad weather. The intention is to port and the load was accompanied on
Valles, S. Stroebele, S. Oberti, P. Gutierrez Cheetam,
M. Kiekebusch, C. Soenke, E. Aller-Carpentier,
complete the commissioning of the Multi foot all the way to monitor the smooth-
P. Jolley, J. Vernet, A. Manescau-Hernandez, L. Unit Spectroscopic Explorer (MUSE) with ness of the ride. The replacement began
Mehrgan, G. Calderone, A. van Kesteren, G. Chiozzi, the GALACSI Wide Field Mode (WFM) at with the removal of the Beryllium M2 mir-
H. Sommers, D. Dorigo, T. Bierwirth, J.-P. Kirchbauer, the end of the summer 2017, with Science ror. Then within one day the Dornier hub
S. Huber, G. Fischer, A. Haimerl, S. Leveque, P.
Amico, G. Hubert, S. Brillant, P. Baksai, J.C. Palacio,
Verification planned for August 2017. was removed and the new M2 hub, with
I. Munoz, E. Fuenteseca, P. Bourget, P. Hibon, F. Commissioning of the High Acuity Wide its DSM dummy weight, installed instead.
Selman, G. Hau, S. Egner, T. Szeifert, J.C. Guerra. field K-band Imager (HAWK-I) and the Three days later the DSM was installed in
8 The Messenger 168 – June 2017
Figure 1. A jubilant team 0.5 arcseconds at the time of the expo-
after the installation of
sure); see Figure 2, right. This measure-
the DSM on UT4.
ment demonstrates that the optical qual-
ity of the DSM in non-adaptive optics
mode allows seeing-limited observation
even under excellent seeing conditions.
The next step consisted of assessing
the changes in the operation of the active
optics. The strategy was to record the
active optics aberration measurements of
the telescope after application of the so-
called “OneCal”, the look-up table for
the primary mirror (M1) modes versus alti-
tude. Comparisons were made between
the Dornier and the DSM. The values
are very similar between both, and the
active optics functionality and operational
its hub (see p. 7). Using the laser tracker, new M2 unit is fully comparable to that aspects are preserved with the DSM as
it was possible to verify that the DSM hub experienced with the old Dornier. well. The secondary chopping was also
ended up, after its installation on the tele- tested and behaved as expected. Only
scope, within 1 mm of the Dornier hub’s The new magnitude zero points for two points remained to be examined —
position, while its longitudinal axis was HAWK-I were found to be identical, within the flexure of the DSM reference body
colinear within 1 arcminute. Calibrated 3 %, to the former values and the emis- and the DSM flattening vector.
mechanical spacers and alignment tools sivity was measured as 25 % for the
allowed this feat, as well as the expertise Dornier and 24 % for the new M2 unit. The trefoil and astigmatism terms evolve
of the optical engineers in Garching and The plate scale change was measured at with altitude as can be seen in Figure 3.
Paranal. The whole operation was led by 1.00047 ± 0.0005 on the Nasmyth B Only the terms along the altitude axis
the Paranal mechanical team under the guide probe, which compares to 1.00067 show a variation. This does not come as
close supervision of the contractor Micro- when measured directly on HAWK-I; a surprise as it was known that the refer-
gate and the Garching DSM team. these results mean that, for all practical ence body of the DSM is subjected to
purposes, the plate scale change is this sort of deformation. At the zenith, the
It is amazing to think that, after such an negligible. reference body is deformed in a threefold
intrusive and major operation on the tele- sag shape (trefoil) because of the system
scope, the first pointing on sky was suc- A series of 10-second J-band images of three supporting points. At the horizon
cessful, with pointing errors of the same were taken of the globular cluster M30 this deformation evolves toward an astig-
magnitude as usual, and the active loop using the new M2 unit. Figure 2 (left) matism. The left plot in Figure 3 shows
was closed successfully after the first shows one of the best images obtained that this variation is seen by the active
iteration! Figure 1 illustrates the effect of with the DSM, with a full width at half optics of the telescope and corrected by
this achievement on the whole team. maximum (FWHM) of the star images of M1. However, the level is quite acceptable
0.37 arcseconds (visual band seeing was and, since the end of the commissioning,
Telescope re-commissioning
During the first nights after installation,
basic tests were carried out to verify
the behaviour of the DSM hexapod. The
focusing motion was as expected and
the three focal planes could be accom-
modated within the DSM focusing range.
The impact of M2 centring on the tele-
scope coma was measured using the
GRAAL MCM wavefront sensor. Excellent
agreement between the centring of the
old Dornier and the new M2 was achieved,
and the GRAAL MCM mode proved
Figure 2. Left: A J-band image taken at a low airmass
extremely useful during all the telescope of part of the globular cluster M30. Right: An analysis
recommissioning phases. It also shows of the point spread function from multiple star
that mechanical flexure introduced by the images; the FWHM is 2 pixels (0.37 arcseconds).
The Messenger 168 – June 2017 9
Telescopes and Instrumentation Arsenault R. et al., The Adaptive Optics Facility
Figure 3. Left: The d ifference in New M2 Unit w.r.t. Dornier Dornier w.r.t. Dornier (different nights)
OneCal residual aberrations 1500 1500
between the DSM and the old
Dornier M2 unit as a function 1000 trefoil 1000
of zenith distance (ZD). Zernike
pairs of orthogonal modes for
Aberration value
Aberration value
500 500
trefoil and astigmatism are
shown. Right: Same as left fig-
ure but for two different sets 0 0
of measurements of the Dornier 0 10 20 30 40 50 60 70 0 10 20 30 40 50 60 70
M2 unit on different nights, –500 –500
showing the typical noise level.
The DSM shows clear trends –1000 astigmatism –1000
of the astigmatism and trefoil
aberrations with altitude (zenith
–1500 –1500
distance). ZD (degrees) ZD (degrees)
the active optics has managed this
HD 49798 Before After
change without issue. Note that the cor-
responding mode amplitude applied in the K
DSM flattening vector has been modified
to ensure that the horizontal axis crosso-
ver occurs at a typical operation airmass.
The same type of analysis reflected a
slightly higher scatter in the higher M1
mode amplitudes. We believe that this is
due to some high-order aberrations in
the DSM flattening vector. After these
measurements a calibration was carried
H+K
out to optimise the DSM flattening vector
and reduce its content in high-order
aberrations.
Finally, a detailed analysis of the field
stabilisation performance took place.
Many small issues were encountered,
resulting from the telescope environment
and the somewhat different control
parameters required by the DSM, but all
were progressively resolved. The final per- H
formance is certainly adequate. The only
remaining issue is poorer performance
when the telescope is facing into a strong
wind. More data need to be recorded
to fully understand the root cause of this
problem before it can be fixed.
An analysis of the field stabilisation
closed-loop rejection transfer function
was performed. For a control frequency
J
of 32 Hz, integration time of 0.01 s and
control parameters of Kp = 0.7, Ki = 1.5
and Koffload = 0.02 and a 3 Hz cutoff fre-
quency, a 6 dB overshoot (> 45° phase
margin) was observed.
Figure 4. PSF samples for the star HD 49798. The
“Before” and “After” columns refer to images obtained
with the Dornier M2 unit and the new DSM M2 unit,
respectively. The external seeing values were similar
in both cases.
10 The Messenger 168 – June 2017UT4 instrument recommissioning 2000 2000 10.0
9.5
To complete the recommissioning
9.0
process, the instrument scientists of 1500 1500
HAWK-I, MUSE, SINFONI and the VLTI 8.5
performed a dedicated set of tests to
Y (pixels)
Y (pixels)
8.0
assess the behaviour of these instruments 1000 1000
7.5
after the new M2 installation. These
tests addressed several aspects of the 7.0
instruments’ performance; we show here 500 500 6.5
only a few excerpts from the recommis- 6.0
sioning reports. Figure 4 shows a sample
0 0 5.5
of S
INFONI PSFs and corresponding 0 500 1000 1500 2000 0 500 1000 1500 2000
Strehl ratios in different bands for the star X (pixels) X (pixels) 5.0
HD 49798. The results are essentially
identical, except in the J-band where high oped for this purpose; it is based on sin- Figure 5. Images of the behaviour of the FWHM
across HAWK-I images in Y-band at airmass 1.0.
spatial frequency residuals can be noticed gle conjugate AO, making use of a 1 kHz
Left: with the Dornier M2 unit; Right: with the DSM.
(static speckles around the diffraction – 40 × 40 subaperture wavefront sensor The scale shows the FWHM in pixels (pixel scale is
limited core); these residuals are due to (WFS) looking at a bright natural guide 0.106 arcseconds) and annuli around the star posi-
the high spatial frequency aberrations star on-axis, therefore fully exploiting the tions indicate measured ellipticity.
of the DSM optical surface. The situation 1172 actuators of the DSM. The tests
was later improved by calibrating and were carried out during a run in February transported to UT4 and installed on the
updating the reference vector position of 2017. Unfortunately, many nights were Nasmyth platform (Figure 7). Precautions
the DSM when in non-AO mode. lost to high humidity and only slightly were taken to protect the MUSE hardware
more than half of the ten nights could be during installation (a special protective
The HAWK-I recommissioning report used for on-sky tests. The result is that fence was designed and manufactured).
also thoroughly reviewed several perfor- less time was available to optimise the First light was obtained on 20 March
mance criteria for the instrument. The performance. In particular, not enough on GALACSI, despite an emergency tele-
Two Micron All Sky Survey (2MASS) time was available to characterise the scope shutdown which delayed the
Touchstone Fields were observed and non-common path aberrations and apply GALACSI installation by one week.
reduced using the new Cambridge an accurate offset for them on the DSM.
Astronomy Survey Unit (CASU) pipeline. Nevertheless, excellent images and per- In April 2017, there was another on-sky
The variation of the FWHM across the formance could be obtained and all the commissioning run during which many
whole field of view was compared and servo-loops and offloads could be vali- technical tests were conducted to reliably
appeared as expected (see Figure 5). dated in this technical mode (this is, how- enable the full adaptive optics correction
The ellipticity of the star images was also ever, not a science observing mode; see performance of the GALACSI WFM,
examined in the different fields. The Figure 6). making use of the DSM and the 4LGSF
report concluded that the installation of (Hackenberg et al., 2014; Bonaccini Calia
the new M2 unit has had no impact et al., 2014; Holzlöhner et al., 2008;
on the overall performance of HAWK-I. First commissioning of the GALACSI Holzlöhner et al., 2010; Holzlöhner et al.,
Wide Field Mode 2012; Amico et al., 2015). The complete
The reports on MUSE and VLTI also automatic acquisition sequence was run
concluded that the behaviour remained On 12 March 2017, following re-integration on numerous occasions and timed. The
similar before and after the installation of and verification in the NIH, the GALACSI acquisition involves presetting the tele-
the new M2 unit. Small differences were module (La Penna et al., 2014; Arsenault scope to the target, acquiring the 4 Laser
observed in behaviour, enough to realise et al., 2013b; Stuik et al., 2012) was Guide Stars within the 5 arcsecond field
that the M2 has been exchanged, but
there was certainly no loss in performance
with respect to the Dornier M2 unit.
Figure 6. Left: K-band
narrow filter image
DSM commissioning with the GRAAL of a double star with
0.2 arcsecond separa-
Maintenance and Commissioning Mode tion, obtained with
GRAAL MCM. Right:
The last step of the new M2 commis A bright star image
sioning was the verification of the per exhibiting 80 % Strehl
ratio (also with K-band
formance of the DSM in AO mode. The narrow filter). The seeing
GRAAL MCM mode (Arsenault et al., was 0.55 arcseconds
2014b; Paufique et al., 2012) was devel- at the time.
The Messenger 168 – June 2017 11Telescopes and Instrumentation Arsenault R. et al., The Adaptive Optics Facility
Figure 7. Left: GALACSI
being hoisted through
the azimuth hatch after
transport from the
Paranal New Integration
Hall to UT4. Right: The
very tight margin to
manoeuver this sensitive
module between the
Nasmyth acquisition
and image rotator unit
and the MUSE fore-
optics can be seen.
of view of the four GALACSI wavefront dation of the optical quality of the images the atmospheric specification (~1.1 arc-
sensors, performing the detection and delivered by GALACSI to MUSE. Figure 8 seconds) and the target was low in the
centering of the tip-tilt natural guide star, shows that, thanks to a rigid design and sky (zenith distance 50°). This is a very
and then closing all the loops. The final good optical alignment, the stability of good first sign that the GALACSI WFM
results are impressive; after a few nights the pupil shift is pretty good from zenith performs as specified. The ratio of turbu-
spent on improving the automatisation down to 35° altitude, meaning that a lence in the first 500 metres above the
of this process, the overhead for the AOF compensation strategy for this misalign- telescope to the total turbulence given
acquisition after the telescope is ready ment may not be needed, thus simplify- by the SLOpe Detection And Ranging
(two active optics cycles) was measured ing the GALACSI operations. (SLODAR) measurement and the internal
to be less than one minute (50 seconds). estimation was ~ 90 % — i.e., quite high
It should be remembered that the specifi- Rejection transfer functions have been — a situation which is best suited to
cation for the overhead was 5 minutes measured for both the high-order correc- ground-layer AO correction (Kuntschner
and the goal 2 minutes. tion loop and the tip-tilt loop. Both look et al., 2012). Figure 9 illustrates this cor-
good and can be fitted nicely by the rection but much better results were
Amongst many performance tests con- model of the dynamic system with respec- obtained later.
ducted, one of them consisted of evalu tively 1.3 ms and 4.3 ms of pure delay.
ating the stability of the registration The results obtained during later nights
between the actuator pattern of the DSM System performance has been finally improved somewhat, and the statistics
and the WFS sub-aperture pattern. Shifts characterised. A gain of 1.5–2 in FWHM showed much better performance. The
with respect to one another are due to at 750 nm was observed between open gain between GLAO and non-GLAO
mechanical flexure in the large distance loop (with telescope field stabilisation) depends strongly on the fraction of turbu-
between them and could lead to a degra- and full closed loop. The seeing matched lence in the lower atmospheric layers.
If a large fraction is concentrated below
30 500 metres, GALACSI will substantially
WFS#1, X shift, 06/04/17
improve the ensquared energy (a gain of
WFS#1, Y shift
four has been obtained). Conversely, if
20 WFS#2, X shift
this fraction falls below ~ 20 %, the gain
Pupil shift (% of sub-aperture)
WFS#2, Y shift will be lower and the observer must
WFS#3, X shift decide whether seeing-limited observa-
10
WFS#3, Y shift tions must be conducted (with shorter
WFS#4, X shift acquisition time and without lasers) or
0 WFS#4, Y shift simply another mode (MUSE NFM) or
WFS#1, X shift, 11/04/17 instrument. This information is provided
WFS#1, Y shift from Multi-Aperture Scintillation Sensor
–10
... (MASS) and D ifferential Image Motion
Figure 8. The shift in pupil Monitor (DIMM) data at the Observatory.
– 20 alignment on the WFS sub- Figures 10 and 11 demonstrate the ens-
aperture in X and Y for all quared energy performance with open
four LGS sensors is plotted
– 30 for two dates (see legend).
and closed loop, allowing a first assess-
30 40 50 60 70 80 90 The shift is expressed in ment of gains, but with limited statistics.
Telescope altitude (degrees) percent of a sub-aperture. From Figure 11, one can determine that
12 The Messenger 168 – June 20173000 Figure 9. The quality of
the image enhancement
2500 by GLAO correction is
illustrated by before
and after images (left)
2000 and profiles through the
Intensity
image centres (right).
1500 See text for full descrip-
tion.
1000
500
0
0 10 20 30 40 50 60
Pixels
30 30
Open loop
25 Closed loop 25
Number of occurences
Number of occurences
20 20
15 15
10 10
5 5
0 0
0 5 10 15 20 25 30 35 0 1 2 3 4
Percentage of ensquared energy in 0.2ೀ spaxel at 750 nm Ensquared energy gain in 0.2ೀ spaxel at 750 nm
Figure 10. The distribution of values of ensquared Figure 11. The distribution of gain in ensquared
energy per 0.2 arcsecond spaxel with GLAO loop is energy per 0.2 arcsecond spaxel with GLAO loop
shown for closed loop (yellow) and open loop (blue; correction is plotted.
only with field stabilisation).
a gain of 2.0 can be obtained about 69 % Finally, we could verify that the sensitivity Conclusions: AOF is on-sky!
of the time, a gain of 1.9 76 % of the time of GALACSI was consistent with that
and a gain of 1.8 83 % of the time. We will measured on ASSIST in Garching. The Since March 2017, the AOF has been
closely follow up how these histograms tests were performed on an 18.6 mag fully installed on UT4. The 4LGSF was the
evolve as more statistics are collected nitude star, the loop was closed and was first AOF component to be bolted onto
with successive commissioning runs. stable, and the performance was within the telescope and it is fully commissioned
specification (the specified limiting mag on-sky (first light was in April 2016). Then
During one of the commissioning nights, nitude of GALACSI is 17.5). Figure 13 the new M2 unit (DSM) was installed
the patch of sky where we pointed shows the raw image on which the loop and replaced the old Dornier M2 unit in
happened to have a nice target in the is closed (left), and the resulting images October; since then, the new M2 unit is
middle, so we couldn’t resist taking from averages of 50 frames (centre) routinely being used by the TIOs to make
images at 850 nm with the commission- and 12 000 frames (right). The 50-frames science observations with the suite of
ing camera (Figure 12). The left-hand average will be shown in the GALACSI UT4 instruments. GRAAL was attached
image of Saturn was taken with field sta- display panel, so that the user can to the telescope in late 2016, but will not
bilisation; the right hand image with be confident that the loop is locked on be fully commissioned until the end of
full GLAO. The seeing was fair (0.8 arc- a star. 2017. Last but not least, GALACSI is
seconds) and the pointing was almost at now also available at Paranal. GALACSI
zenith for these observations. WFM commissioning has begun and the
The Messenger 168 – June 2017 13Telescopes and Instrumentation Arsenault R. et al., The Adaptive Optics Facility
Mag 18.6 – 1 frame 50 frames 12 000 frames or Figure 12. (Above) S aturn
@ 200Hz average 1 minute average observed without (left) and with
25 (right) GLAO. The insets show the
60 35 effect of the correction on some
50 30 stellar images.
20
40 25
30 20 15
20 15 Figure 13. Individual 200 Hz frame
10 showing the tip-tilt star s ignal (left),
10 10
with 50 (centre) and 12 000 (right)
0 5 5 frames averaged. The star magni-
–10 0 tude is 18.6 and the spaxel size is
0 0.2 arcseconds.
performance is found to be extremely Figure 14. The writing is
on … the sky!
promising so far.
As an anecdote, the AOF team took the
picture shown in Figure 14, illustrating
better than a long speech and without
ambiguity that the AOF is now on sky
(for readers interested in the technical
details, each character is created using
one laser guide star by controlling its
associated 1 kHz jitter mirror; the image
was recorded during a 4 s exposure of
the Laser Pointing Camera installed on
the telescope top ring).
References
Amico, P. et al. 2015, The Messenger, 162, 19
Arsenault, R. et al. 2010, The Messenger, 142, 12
Arsenault, R. et al. 2013a, The Messenger, 151, 14
Arsenault, R. et al. 2013b, Third AO4ELT
Conference, Florence, Italy Briguglio, R. et al. 2014, Proc. SPIE, 9148, 914845 Kuntschner, H. et al. 2012, Proc. SPIE, 8448,
Arsenault, R. et al. 2014a, Proc. SPIE, 9148, 914802 Hackenberg, W. et al. 2014, Proc. SPIE, 9148, 844808
Arsenault, R. et al. 2014b, The Messenger, 156, 2 91483O La Penna, P. et al. 2014, Proc. SPIE, 9148, 91482V
Arsenault, R. et al. 2016, The Messenger, 164, 2 Holzlöhner, R. et al. 2008, Proc. SPIE, 7015, 701521 Manetti, M. et al. 2014, Proc. SPIE, 9148, 91484G
Bonaccini Calia, D. et al. 2014, Proc. SPIE, 9148, Holzlöhner, R. et al. 2010, A&A, 510, A20 Paufique, J. et al. 2012, Proc. SPIE, 8447, 944738
91483P Holzlöhner, R. et al. 2012, Proc. SPIE, 8447, 84470H Stuik, R. et al. 2012, Proc. SPIE, 8447, 84473L
14 The Messenger 168 – June 2017Telescopes and Instrumentation DOI: 10.18727/0722-6691/5020
ESO Public Surveys at VISTA: Lessons learned from
Cycle 1 Surveys and the start of Cycle 2
Magda Arnaboldi 1 from the ultraviolet (0.33 micron) through and extended wavelength coverage.
Nausicaa Delmotte1 to the Ks-band (2.15 microns). In 2012, These spectrographs will be used for
Dimitri Gadotti 1 Public Spectroscopic Surveys also follow-up studies of interesting candidates
Michael Hilker 1 started using the spectrographs Ultra identified via their colours and/or morpho-
Gaitee Hussain1 violet and Visual Echelle Spectrograph, logical properties from the Public Surveys
Laura Mascetti 2 UVES, GIRAFFE and the ESO Faint Object and/or space missions (for example, the
Alberto Micol 1 Spectrograph and Camera, EFOSC2. ESA satellite, Gaia, and eROSITA). In the
Monika Petr-Gotzens1 The spectroscopic surveys were further current ESO instrument plan, the 4MOST
Marina Rejkuba1 expanded in 2014 with the addition of spectrograph will replace the wide field
Jörg Retzlaff 1 two new surveys on Unit Telescope 3 near-infrared camera, VIRCAM, on VISTA,
Robert Ivison1 (UT3) using the VIsible MultiObject Spec- with commissioning being planned for the
Bruno Leibundgut 1 trograph (VIMOS). end of 2020.
Martino Romaniello1
As the first cycle of ESO Public Surveys
with VISTA approached its sixth year VISTA Cycle 1 surveys: time allocation
1
ESO of successful telescope operations in and current status
2
TERMA GmbH, Europahaus, Darmstadt, 2015, ESO opened the call for submis-
Germany sion of letters of intent for a second cycle The first cycle of approved VISTA Public
of Public Surveys to run until the end of Surveys includes six imaging projects1
2020, the expected date for the decom- that began observations in April 2010.
The ESO Public Surveys on VISTA serve missioning of the VISTA InfraRed CAMera Figure 1 shows the completion fractions
the science goals of the survey teams (VIRCAM). Thirteen letters of intent were of the requested time in their observing
while increasing the legacy value of ESO submitted by the community by the plans with respect to time. An overview
programmes, thanks to their homoge- deadline of October 2015; these involved of each of the Cycle 1 surveys is given in
neity and the breadth of their sky cover- more than thirteen Principal Investigators Table 1 along with their full titles and
age in multiple bands. These projects (PIs) and 517 co-investigators, with an acronyms; a more complete description
address a variety of research areas: oversubscription factor of over twice the of each of these surveys is presented in
from the detection of planets via micro- total available observing time. The joint The Messenger 154 (2013).
lensing, to stars, the Milky Way and VISTA /VST Public Survey Panel (PSP)
Local Group galaxies, to extragalactic was asked to review these letters to iden- The overall time allocations for these sur-
astronomy, galaxy evolution, the high- tify a well-balanced scientific programme veys are between 1500 and 2200 hours,
redshift Universe and cosmology. In for VISTA. An important consideration except for the VHS, which requires 4710
2015, as the first generation of imaging for the VISTA Cycle 2 Public Surveys was hours for completion. The VHS takes up
surveys was nearing completion, a the exploration of scientific and observing 28 % of the allocated telescope time to
second call for Public Surveys was parameter space that had not been date, while about 12 % goes to each one
opened to define a coherent scientific covered by the previous surveys. These of the other surveys; additionally Chilean
programme for VISTA until the com recommendations were passed to the regular and other open-time programmes
missioning of the wide-field multi-fibre Observing Programmes Committee have been allocated 3 % and 4 % of time
spectrograph, 4MOST, in 2020. This (OPC) and the ESO Director General. respectively. Figure 2 shows a pie chart
article presents the status of the Cycle 1 summarising the time committed to the
surveys as well as an overview of the In this article, we provide an overview of VISTA surveys between Periods 85 and
seven new programmes in Cycle 2, the status of the VISTA imaging surveys 99, as a percentage of the total allocated
including their science goals, coverage that started in 2010 and their impact in telescope time.
on the sky and observing strategies. terms of data releases and refereed
We conclude with a forward look at the publications. We then describe the selec- Based on statistics gathered over three
Cycle 2 data releases and the timelines tion process of the new surveys and pro- years (from October 2012 to September
for their release. vide a summary of their science goals, 2015), the total execution time of suc-
observing strategies, and the content and cessfully observed OBs from the VISTA
timelines of their planned data releases. Cycle 1 surveys is 2340 hours per year.
Introduction The time for open and Chilean time
Looking further ahead, the construction amounts to about 6 % of the total time in
ESO has operated two telescopes that and deployment of two wide-field spec- that period. Thus, 2490 hours/year are
are mostly dedicated to Public Surveys trographs is foreseen: the Multi Object available for successful observations with
since 2010: namely, the 4-metre Visible Optical and Near Infrared Spectrograph VISTA. In 2015, the projected observations
and Infrared Survey Telescope for Astron- (MOONS; Cirasuolo et al., 2011) and the for the VISTA Cycle 1 surveys showed
omy (VISTA; Sutherland et al., 2015) 4-metre Multi Object Spectroscopic that observing time would become availa-
and the 2.6-metre VLT Survey telescope Telescope (4MOST; de Jong, 2011) on the ble in certain right ascension (RA) ranges;
(VST; Arnaboldi et al., 1998; Capaccioli & VLT and VISTA respectively. They have hence the need to release a call for VISTA
Schipani, 2011). These provide coverage large multiplexing wide field capabilities Cycle 2 Public Surveys.
The Messenger 168 – June 2017 15Telescopes and Instrumentation Arnaboldi M. et al., ESO Public Surveys at VISTA
Table 1. General obser-
Survey ID, Science Area Filters Magnitude Observing time to
vational parameters for
title & homepage topic (square degrees) limits 1 April 2017 (hours)
the Cycle 1 VISTA Public
UltraVISTA Deep high-z 1.7 Deep Y J H Ks 25.7 25.5 1780 Surveys1. The columns
http://home.strw.leidenuniv.nl/~ultravista/ 25.1 24.5 illustrate the Public Sur-
0.73 Ultra deep Y J H Ks 26.7 26.6 vey programme acronym
26.1 25.6 (column 1), a broad
NB118 26.0 classification of the sci-
entific goal (column 2),
VHS — VISTA Hemisphere Survey All sky 17800 Y J H Ks 21.2 21.1 4490 the targeted total area
http://www.ast.cam.ac.uk/~rgm/vhs/ 20.6 20.0 (column 3), the filters
VIDEO — VISTA Deep Extragalactic Deep high-z 12 Z Y J H Ks 25.7 24.6 1799 (column 4), the magni-
Observations Survey 24.5 24.0 tude limits (10σ AB for
http://www-astro.physics.ox.ac.uk/~video 23.5 VMC; otherwise 5σ AB)
in the different filters
VVV — VISTA Variables in the Via Lactea Milky Way 560 Z Y J H Ks 21.9 21.1 2157/Completed (column 5) and the
http://vvvsurvey.org/ 20.2 18.2 observing hours com-
18.1 pleted up to 1 April 2017
(column 6).
VIKING — VISTA Kilo-Degree Infrared Extragalactic 1500 Z Y J H Ks 23.1 22.3 2384
Galaxy Survey 22.1 21.5
http://www.astro-wise.org/projects/VIKING/ 21.2
VMC — VISTA Magellanic Clouds Survey Resolved SFH 180 Y J Ks 21.9 21.4 1759
http://star.herts.ac.uk/~mcioni/vmc/ 20.3
100 % Chile
Open UltraVISTA
VHS VMC
Percentage of completion (OB hours)
80 % VIKING
VVV
VMC
60 % UltraVISTA VIKING VHS
VIDEO
40 %
VVV
20 % VIDEO
Figure 2. Pie chart showing VISTA time allocation to
0% the Cycle 1 and 2 surveys, as well as Chilean and
open time programmes, since Period 85.
9
10
0
11
1
12
2
13
3
14
4
15
5
16
6
/1
/1
/1
/1
/1
/1
/1
/0
5/
5/
5/
5/
5/
5/
5/
11
11
11
11
11
11
11
11
Date
Figure 1. The percentage completion for the Cycle 1 the data centres2, 3, 4 provide for uniform science data products for VISTA, which
VISTA Public Surveys with respect to the allocated
data with many astrophysical applica- have been superseded by newer prod-
time. Note that completion fractions include the
observations taken during dry runs in 2009. The VVV tions. The VISTA survey data are listed ucts but remain available on demand by
completed its observations in October 2015. VIKING on the Phase 3 data release manager archive users, for example, for verification
completed observations by the end of 2016, but page5 and can be searched using the purposes.
requires the re-observation of a few tiles that were
ESO Science Archive Facility6 (SA F,
found to be out of the specified constraints. Ultra-
VISTA, VHS, VMC and VIDEO all had completion see A rnaboldi et al., 2014; Retzlaff et al., Astronomers have access to images,
fractions larger than 90 % by April 2017. 2016). covering 11 × 103 square degrees area
in Y-, J- and Ks-bands from VHS, and
Current active releases provide more deep images plus catalogues from the
than 40 TB of science data products UltraVISTA, VIDEO and VIKING surveys.
The scientific impact of the VISTA surveys from the VISTA Cycle 1 surveys which For example, they can extract measure-
and legacy value of the data products have been delivered by the teams. These ments from the billion-source catalogue
products, including calibrated images, for stars in the Milky Way bulge from the
The VISTA surveys produce large, coher- source lists, photometric catalogues and VVV survey, or from the light curves of
ent data sets. The constant monitoring of light curves for multi-epoch observations, Cepheid stars in the Magellanic Clouds
the system stability and the observations are available to the community for their in VMC. Community use can be quanti-
of standard stars in combination with the independent scientific research. There fied by means of the downloaded volume
extensive data reductions carried out by are also approximately 12 TB of additional of the VISTA Cycle 1 survey data, and the
16 The Messenger 168 – June 2017You can also read
