H.E.S.S. Project Chronology
Milestones and events in the history of the project
See also image collections with
high-quality versions of selected images and other material
for use in printed
H.E.S.S. Phase I:
With the inauguration of the four Phase I telescopes in September 2004 and first exciting
physics results, the construction and commissioning of H.E.S.S. Phase I is complete (and therefore
this part of the project chronology); the
telescopes are in routine operation. For further scientific results, please see the
and the H.E.S.S. Source of the Month.
- November 04
- The H.E.S.S. Collaboration publishes the first image of a supernova where
the shell is resolved as a source of TeV gamma rays
(Nature 432, 75 (2004),
Nature article ,
MPG press release (in German) ,
CNRS/IN2P3/CEA press release (in French),
PPARC press release ,
- October 04
- First H.E.S.S. physics results published in a refereed journal:
Very high energy gamma rays from the direction of Sagittarius A* (Astronomy and Astrophysics, v.425, p.L13-L17 (2004)).
- October 2nd: Open Day at the H.E.S.S. site attracts about 300 visitors.
See here for pictures.
The preceeding public lecture
on Oct. 1 was also very well attended, and was followed by a lively discussion.
- September 04
- September 29 - October 1st:
H.E.S.S. collaboration meeting at the
Gemeindezentrum Foundation in Windhoek.
- Inauguration of the four H.E.S.S. Phase I telescope, with an
workshop at the Heja lodge on Sept. 27 and the
official inauguration by
Prime Minister Gurirab on the H.E.S.S. site on Sept. 38. The event included
a presentation of the H.E.S.S. project by Heinz Völk, messages by
Prof. Kiremire (UNAM), Dr. Mokhele (NRF/RSA), Dr. Spiro (IN2P3/France),
Prof. Lüst (MPG/Germany), Dr . Giacobino (French Ministry), Dr. Berghöfer
(BMBF/Germany), Mr. Faro (French Embassy), Dr. Massing (German Embassador) and
the keynote speech by the Prime Minister.
See here for pictures, and
the inauguration web pages.
brochure created for the inauguration provides information about
the H.E.S.S. instrument, the science, and first results
version with full-resolution images - 15 MB).
- July 04
- An extensive range of H.E.S.S. physics results is presented at the
International Symposium on
High Energy Gamma-Ray Astronomy in Heidelberg, July 26-30. Among the
highlights are the TeV gamma ray image of SNR 1713, for the first time resolving
the supernova shell as the origin of the radiation, the unidentified TeV
gamma-ray source in the PSR B1259 field of view - showing for the first time
two sources in a single field of view - and the precise measurements of
gamma rays from the direction of the Galactic center.
- April 04
- H.E.S.S. collaboration meeting in Durham, April 5-7.
- March 04
- DAQ upgrade adding 4 dual 2.8 GHz nodes and memory upgrade of
farm nodes. Reorganization of control framework to speed to run
startup times and data preanalysis.
- Measurements to characterize performance of local and central trigger
system with all telescopes.
- Discovery of PSR 1259-63 in VHE Gamma-Rays with H.E.S.S.:
detection of very-high-energy gamma-ray emission
from the binary millisecond pulsar PSR 1259-63 at the 5.9-sigma level.
The source was observed for a total of 4.6 hr live-time between Feb. 26 and Mar. 5
with the full four-telescope Cherenkov array. Preliminary estimates yield a flux
at about 10 percent of the level of the Crab nebula (0.4 photons/min gamma-ray
excess detected after selection cuts).
Announced as IAU telegram /
Astronomer's Telegram. PS 1259-63 is one of the few known pulsars
forming a binary system. The pulsar is in a highly elliptical orbit
around a star with about 10 times the mass of the sun. The massive "Be"
star is very hot and is ejecting material from its surface, in form
of a disk around the equator (see
for an illustration of a Be star).
Every 3.5 years, near the point of closest
approach, the pulsar passes through this disk and emerges 30 days later.
During the this time, electrons accelerated
by the pulsar find a dense target of photons from the Be star, which are
upscattered to high energies and detected as gamma rays.
For more information on this pulsar, see e.g.
- January 04
- Since January 04 regular operation of the 4-telescope H.E.S.S. system.
- December 03
- The last of the four H.E.S.S. Phase I telescopes was completed by installing
At the same time, the cameras of the other three telescopes were
upgraded to the latest state, including an improved readout bus.
coincident events were observed in the night of Dec. 10, tracking Pictor A.
See here for an image of the full telescope system.
- October 03
- A TOO program for 215 ksec of joint multiwavelength observations of PKS2155 with RXTE
was triggered on Oct. 17, based on the TeV activity of the source.
- October 15-17: H.E.S.S. general meeting in Berlin, concentrating on a review of the
data analysis and the discussion of the observation program for 2004.
- September 03
- Alignment of mirrors on the fourth and final Phase I telescope was
completed on Sept. 28.
- The ROTSE 3c robotic telescope
for GRB observations is operating (see
here for general information about the ROTSE project).
About 1/3 of its observation time is available to H.E.S.S. and is
currently used for optical AGN monitoring; first light curves have
been generated (e.g. for PKS 2155-304).
- The third camera has been installed on telescope CT4 and
was successfully commissioned. The telescope is now included
in the central trigger system, which is operated in a '2 out of
3 telescope' requirement. Trigger rates are in the range of
220 Hz. About 1/3 of all triggered events are 3-fold coincidences,
the remaining 2/3 involve only two telescopes.
Here one of the early
3-fold coincident events (from September 22).
- For the first time, online event building is active,
combining the images from all telescopes in a single file,
synchronized by the central trigger system. The data streams
from all telescopes are directed to a single processor,
where data are buffered and sorted. Every few seconds, the
data stream is redirected to a different CPU to balance the
- Quasi-online calibration and data analysis is now
running on the processor farm in Namibia, and provides
detailed monitoring information and results of a
full image analysis shortly after a data run has ended.
- Installation of mirrors on the fourth telescope ("CT1") was completed
in early September and the alignment of mirrors is in progress.
(For technical and historical reasons, the telescope labels ("CT1" through "CT4")
differ from the order of commissioning; the first telescope ready for
data taking was CT3, followed
by CT2, CT4, and finally CT1).
- August 03
- Results on the detection of the Crab Nebula and of the AGN
PKS 2155 were presented at the International Cosmic Ray Conference
in Kashiwa, Japan, together with numerous more technical contributions.
Also reported were data on Supernova 1006, where no signal could be
detected. A compilation of the 14 conference contributions can be
slides of (some of) the talks and the posters are reproduced
- Telescope coincidence trigger now in routine operation;
telescope trigger thresholds were lowered from 4 pixels above
4 p.e. to 3 pixels above 4 p.e., increasing the telescope
trigger rate from about 250 Hz to 2 kHz, and resulting in a
two-telescope coincidence rate of about 100-120 Hz.
- Shift operation is becoming routine, with close to 80%
of the dark time used for data recording.
Installation of mirrors on the fourth telescope has started
and is progressing well.
- July 03
- Alignment of the mirrors of the third telescope was completed
in early July. At the same time, the optical characteristics of the
first two telescopes were checked once more. No variation in the point spread
function is seen over a period of a year, demonstrating the excellent
stability of the dish.
- June 03
- The ROTSE 3C telescopes is being installed and commissioned
on the H.E.S.S. site
( unloading of the telescope,
telescope in its shelter,
opened for observations).
ROTSE III is a third generation robotic
telescope aiming to locate GRBs; part of its observation time
is available to H.E.S.S. for other purposes. First light was
reported on June 18, with images of Cen A
(full field of view,
- The central hardware trigger system for the telescopes
was installed and commissioned. Is is based on VME units
(top crate in the rack)
and allows to trigger on arbitrary combinations of telescopes,
with appropriate computer-controlled delays to compensate
differences in shower arrival times at the telescopes.
- May 03
- Installation of
mirrors on the third telescope is progressing.
- April/May 03
- Routine data taking with two telescopes pointing at the
same source, but triggered independently. First results
concerning the detection of the Crab Nebula and of the AGN
PKS2155 presented at the "Second VERITAS Symposium on TeV
Astrophysics of Extragalactic Sources" and submitted to the ICRC.
- March 03
- March 5: first two-telescope events were recorded, at this
point still synchronized in software on the basis of event times
in the two telescope. The
distribution of event time differences
between telescopes CT2 and CT3 shows a pronounced peak around t=0
due to coincident stereo events.
- February 03
- Mirrors of the second telescope were realigned to account for
a small shift in focal plance location compared to the dummy
camera used in the initial alignment.
- The camera of the second telescope was installed
arrival of the truck on site,
unloading of the camera body,
the front section of the
camera body is taken off for installation,
transport to the telescope,
rails are used to move
the camera body in,
installation of the front section,
the camera complete with PMT drawers
- January 03
- To verify the absolute timing, one of the H.E.S.S. telescopes
was pointed at the Crab Nebula and the optical radiation from the
pulsar was monitored using a single PMT at the center of the
Cherenkov camera. With only 5 min. of recording time, the
pulsed signal is clearly visible. The
pulsar phase shifts slightly
with time, since pulsar parameters from late December are used
in the analysis.
- After final tests, the second camera is shipped from Paris to Namibia:
the camera is first taken from LPHNE to LLR,
where it is
packed for transport.
The camera drawers
are packed separately. After the second camera has left, the mechanics
of the third camera is brought from LLR to LPHNE, to be cabled and equipped,see
- December 02
- Mirrors on the second telescope were aligned
in late November/early December; the point spread function
of the second telescope is identical to that of the first
telescope is now ready for the installation of the camera.
here images of the
two telescopes with mirrors.
See also the
Xmas version of a telescope
and a peculiar
- October 02
- Mirrors were installed on the second for the four telescopes.
The installation of the 380 mirror facets took less than two weeks;
here pictures of the telescope
on Oct. 26
and on Oct. 31.
- Drives and control system were installed in the remaining
two telescopes, and were tested successfully. All telescopes
can now be steered from the control room.
- September 02
- 2-4 September: Inauguration of the H.E.S.S. Experiment - the First
- Events to celebrate the official start of
operation of the first telescope included an
H.E.S.S. Workshop on Sept. 2 at the Goethe Zentrum in Windhoek and the
inauguration ceremony on Sept. 3 on the H.E.S.S. site,
followed by a reception at the H.E.S.S. residence building.
Speakers at the ceremony were Prof. W. Hofmann (MPIK),
Prof. P. Katjavivi (UNAM), Prof. D. Vignaud, representing IN2P3,
Dr. R. Adam, Dept. of Art, Culture, Science and Technology of
RSA, Prof. H. Völk, representing Prof. P. Gruss (MPG),
B. Faro, French Embassy, German Embassador H. Nestroy, and
the Namibian Minister N. Angula. Pictures from the inauguration
and the workshop are available here.
- The sequence of events was concluded by a
First Light Workshop on Sept. 4, also at the Goethe Zentrum
Scanned articles covering the events in the press are
- August 02
- Due to extensive maintenance work on the camera, little additional
test data are taken.
- July 02
- Test data are being recorded tracking objects
such as PSR 1706-44 or PKS 2155-304. Typical data recording
rates are around 150 Hz.
- June 02
- The 2nd telescope is fully cabled and ready for mirror
- June 11: the first camera is installed and operational!
Images from the final steps of the installation:
installation of Winston cone plate,
test of the mechanism to open the camera lid.
telescope with camera,
First images of cosmic ray showers have been recorded, see e.g.
- Installation of the camera is progressing well; as of early June,
the camera is in
place, see also
here - in the camera shelter -
and tests are underway. Here a view
from above, along the
- May 02
- The camera transport arrived on site on May 23; here
truck with the camera and the
associated equipment, and the
- On May 16, the first camera was shipped from Paris
vis Frankfurt to Namibia:
leaving the lab,
on the truck,
At the same time, the
body of the 2nd camera was brought
to Jussieu, where it will be equipped.
- During commissioning studies, the first two telescopes
("CT2","CT3") were for the first time jointly tracking
an object, with control and readout using the central DAQ system.
Deviations between nominal and actual shaft encoder values
are at the arc-second level.
- April 02
- Analysis of data taken earlier this year shows that the
pointing of the telescopes can be controlled to a few arc seconds,
using a guide telescope observing the sky and a second CCD camera
monitoring the image.
- April 12: Mechanical structures of all four telescopes
are installed on site!
In the background of the
image the first telescope complete with mirrors, to the right
the second, which is currently being commissioned, and on the left the
two final telescopes. In the distance the Gamsberg. More images
- Unfortunately, parts of the
local fauna are very fond of the telescopes, and have found
a new home there.
- Early April: drives of the second telescope are installed.
These drives are upgraded
versions with improved guide wheels and better traction.
- Upgrade of online software in progress.
- March 02
- While lab test of the first camera continue, perparations
for the installation of the camera are in progress in
camera shelter with a moveable roof will serve to protect
the camera from sun and rain.
- Feb. 02
- Tests of the first camera continue in Paris, see e.g.
image of a muon crossing the PMTs.
- Construction on site is progressing:
in the background
the first two telescopes, in the foreground the baseframe of the
third telescope under assembly. The
is already on site (background right).
- All mirrors (380) are installed on the first telescope
a nice view of the dish with its
mirrors, views of the telescope
image of the telescope at
night), and all
(except for one with a drive problem) are fully aligned. The resulting
point spread function at 70o elevation has an rms width of
0.34 mrad; 80% of the light is contained within a radius of 0.42 mrad
(for reference: the pixel diameter is about 3 mrad). A profile of the
point spread function on axis is shown here.
- Jan. 02
- Since mid-January, the 128 kb data link to the site is activated.
- The missing last 20 mirrors were installed on the first
telescope, mirror alignment is being finalized and tests of
tracking and pointing accuracy continue.
- More images from the site, showing
the first two telescopes,
here another view.
- Dec. 01
- At Paris, the assembly of the camera of the first telescope
has been completed and first tests are in progress. Images show
a section of the camera with
Winston cones and PMTs - an appropriate picture for the season -
and the whole camera,
here in another view,
here together with its lid
with partially installed Winston cones.
- More pictures from the site: here
the crew of NEC, the
builder of the telescope structures, and
the first two telescopes with
the Gamsberg in the background.
- Nov. 01
- On Nov. 27/28, the steel structure of the second telescope
was installed in site: here
lifting the dish onto the baseframe and
installation of the camera bock.
Here a picture of both telescopes at sunset.
At the same time, the fourth dish is
nearing completion at
the NEC workshop in Okahandija.
Nov. 4-10: H.E.S.S. collaboration meeting and astrophysics workshop
at Ringberg, to define the initial observation program.
special highlight of the meeting was covered by the local
- First results concerning image quality and image
stability look very good: the
width of the spot size, in the relevant range of elevations,
is very small
compared to a size of the camera pixels, and the
6 mm deformation of the camera masts
between horizon and zenith
is well within specs. (The deformation is the camera masts is monitored
and corrected using LEDs on the camera, viewed by a CCD camera on the
- Oct. 01
- A nice article
in the Namibian Allgemeine Zeitung
covers the progress of H.E.S.S.
- First tests of the mirror alignment procedure were
quite successful: Here the
image of a star in the focal plane before alignment, with the mirror
drive systems at their center position. Each spot
corresponds to one mirror. Compare to the
image after alignment, using about 2/3 of all
mirrors. Alignment is automatized, using the CCD images to
- Commissioning of the telescope steering is progressing:
here the Crab Nebula observed with
the guide telescope attached to the dish of the first
H.E.S.S. telescope. The guide telescope serves to monitor the
precision of the pointing. Images of the guide CCD show that
absolute pointing after a first alignment is good to about
1 arcmin, as expected, and that the rms jitter during tracking
is at the level of 1-2 arcsec.
- Picture of the day:
Namibian desktop .
- The residence building
is nearing completion. Here a
view from the other side and
of the living area.
Final touches are added to the
workshop and the
A security guard is on duty.
- Nicer pictures
of the telescope with mirrors, also
with two of the lightning
protection masts. Here
a large version. See also here.
- Oct 4: first tests of telescope tracking under remote control
from the control room, using the DASH DAQ and control system.
Nominal and actual values of the azimuth and altitude encoders
agree within the encoder resolution of a few arc-sec (rms).
Plot of encoder deviations vs. time,
- Sept. 01
- Funding was approved for the installation of a 2nd tape
library and a farm of 31 dual Pentium processors at MPIK, targeted
(among other applications) at simulations and data handling for H.E.S.S.
Mirrors of the first telescope are installed,
apart from the last 20 mirrors where parts are missing.
With the trained crew, about 40 to 50 mirrors were installed each day.
Installation of the mirrors on the first telescope
is progressing well, see also here;
as of Sept. 6,
139 out of about 380 mirrors were installed.
- Aug. 01
- Installation of cable channels was finalized, and the cables
between the electronics hut and dish/camera were installed.
- The processor farm
consisting of 16 dual 800 MHz
Pentium processors with 1.3 TB disks, DLT8000 tape drives
equipment was installed in the control building and commissioned.
Additional PCs in the control room serve to control the experiment.
- Installation of mirrors has started in the last days of August,
see here and
- Final assembly of camera mechanics is in progress.
- July 01
- The first telescope was properly balanced.
Upgrades to its drives were
implemented, and the drive systems were tested extensively.
Performance of the tracking feedback loop is satisfactory, with
rms deviations between nominal and actual encoder values of about
- The 60 ``drawers'' for the first camera are complete and tested.
- By late July, all 4200 photomultipliers for the first four
cameras (incl. some spares) were delivered to Heidelberg.
- June 01
- Installation proceeds with the
azimuth cable chain, the
altitude cable chains and the drives. Initial tests showed that the
drive systems work and allow
to point the telescopes, but
that certain modifications are required.
- The control building is ready.
In the background the generator building; power is available on the site
One of the two generators,
- The dish of the second
telescope was transported
to the site and assembled there.
- The light pulser system integrated
into the camera lid has been completed in Heidelberg and was
shipped to Paris. There, the assembly of the first camera is progressing,
see e.g. the fitting of the Winston cone plates.
- May 01
- 385 of the
motorized mirror support units - sufficient for the
first telescope - have been completed and
await shipment to Namibia.
- On May 16, the camera masts of the first telescope were installed, see
here. There lower bracing visible
in the first image is removed after installation.
- On May 14, the dish of the first telescope was lifted onto the baseframe.
First, the dish was lifted face down
into the baseframe, see here,
The crane is then used
to turn the dish,
see also here, until it is
in the stable position looking
at the zenith. The
end of a successful day.
- H.E.S.S. collaboration meeting and MC meeting in Paris, May 9-11.
- The body of the first camera has been brought to Jussieu and
is being cabled.
Production and testing of drawers is making good progress;
see here some drawers inserted
into the camera body.
baseframe of the first telescope is erected on site,
see also here. The
platforms of the baseframe also provide
new views of the dish and of the
- April 01
- Construction of the
buildings is progressing:
the control building and
the residence. Unusually late rain and
strange weather cause slight
- The rails for the remaining rails were installed
as well as the
central bearing for the first telescope.
- The trial assembly
of the telescope base frame
is progressing at NEC.
Detail of the elevation bearing
and of one of the nodes.
- The contract with Namibia Telecom concerning the
microwave link to Windhoek has been signed.
- March 01
- The first camera body was delivered to Paris:
with a drawer,
rear side, which will
house the trigger system, the readout and the power supplies,
connectors for the drawers.
- At NEC, the mount for the first telescope is growing;
the image shows one of the
support towers for the
elevation bearings, see also
here. Also, work on the
2nd concentrator has started.
Cables for the mirror drive systems were installed on the
first concentrator by the crew from Hamburg.
- On March 2, the second half of the first concentrator arrived on
(the tanks of the Namibian Brewery in the back are NOT going
to our site!),
arrival on site,
aligning the two halfes,
preparing for assembly.
- Feb. 01
- Thanks to an enormous effort at NEC, the first concentrator
was finished on schedule, and on Feb. 28, the first half was transported
to the site:
bypassing freeway bridges at
at Brakwasser and
on the gravel road,
on the telescope site,
- After a three-week struggle with missing infrastructure
and rain, the
for the first telescope are installed.
The rails are level to 0.2 mm, significantly better than
the minimum requirement of +-1 mm.
- Mid-February: the space frame
and the mirror supports
are added to the dish.
First measurements of dimensions and
angles show that the structure is within tolerences, with very few
- The contract for the control building, the generator
building and the residence has been awarded. Here a
first view of
the control building...
- Jan. 01
dish of the first telescope is
being assembled at NEC.
- Mounting and surveying of the azimuthal rails has started
Progress is slower than planned, due to bad weather and customs problems.
- The H.E.S.S.
processor farm and networking components
are under test at Berlin, before being shipped to Namibia.
One rack contains 8 dual pentiums PCs (another 8 will
be added), the other the
Gbit-switch, disks and tape
drives and their servers.
- Dec. 00
- Just in time for Christmas, the 1:20 model of a
H.E.S.S. telescope arrived at Heidelberg
camera section). It shows the
telescope in the final color, optimized to minimize heating
in the sun during daytime, and halo in the PMT wavelength region
during night time.
arrives at Heidelberg. It will soon be shipped to Namibia
and will be used to access telecope mirrors.
- The first switchboard for the telescope control and
interlocking system was delivered and is under test in Heidelberg, see
- Nov. 00
- Three of the four foundations for the first telescopes
(in the background the Hohenheim communications tower,
which will link the site to Windhoek by a Microwave link),
the pad where the camera will
be parked and locked.
- Progress at NEC:
the radial beams of the telescope dish ("box sections").
(For experts: can you find U. Dillmann, the SBP engineer,
on the foto?)
precision-machined azimuth rails are
packed into a
container to be shipped to Namibia; in the background more
- Oct. 00
- Federal support for german H.E.S.S. groups approved
- Steel structures of telescopes in production at
NEC: welding of dish radial beams,
detail of beam,
central hub of dish.
- Final version of camera drawers under test in Paris:
complete drawer with 16 PMTs and
electronics, front view of PMTs
- Sept. 00
- First set of fabrication drawings of dish released for production
- Progress in the construction of the telescope
foundations is illustrated
See also the
title page of the "Windhoek Observer".
first container leaves MPIK for Nambia, with 200 mirrors,
two azimuth bearings,
tools and workshop machines.
More mirrors are
ready for shipping.
- Aug. 00
Steel for telescope structures (~200 t) delivered to NEC from
Germany and South Africa.
- Construction of telescope foundations started on Goellschau site
Construction office on Goellschau;
Water pipes leading to the H.E.S.S. site are installed;
Excavation of the foundations for the first telescope;
Foundation for the first telescope is being filled with concrete;
Work on the foundation of the second telescope)
- ARS custom integrated readout chips delivered to Paris;
testing of chips commences
- Special production run of comparator ICs for the trigger
ordered from Le Croy
- July 00
- Namibian stamp showing the H.E.S.S.
- Preparation of mirrors starts:
metal mounting plates are
being glued to the mirrors
- June 00
- Campaign to measure night sky brightness in the Gamsberg area
- International Symposium on High Energy Gamma-Ray Astronomy
in Heidelberg, organized by MPIK
- May 00
- HV/divider circuits for 1st telescope delivered to MPIK
- Apr. 00
- Exchange of Notes between Germany and Namibia concerning
H.E.S.S. project signed
- Contract for mount and dish steel structures awarded to NEC, Namibia
- Lease for H.E.S.S. Goellschau site signed
- Start series tests of PMTs at MPIK
- Jan. 00
- First batches of PMTs delivered to MPIK
- Dec. 99
- H.E.S.S. Ringberg Workshop
- Nov. 99
- Mirrors for first telescope delivered and measured
- Sept. 99
- Contract for PMTs awarded to Photonis
- Aug. 99
- Initiate bidding process for mount and dish steel structures
- 1st generation ``Smart Pixel'' 19-PMT prototype operational
- Decision to use ARS-based readout with sector trigger
- July 99
- Cooperation agreement between UNAM and MPIK signed
- Mirrors mounted on Namibia site for long-term exposure tests
- Initiate bidding process for PMTs
- BMBF support for Berlin H.E.S.S. group approved
- May 99
- Visit to Nambia to clarify administrative details,
including representatives of the MPG general administration
- Decision to locate H.E.S.S. on the farm Goellschau in the
Khomas Highland of Namibia
- Contract for design of site infrastructure awarded to
- March. 99
- Proposal by the french groups to use the ARS analogue
memory ASIC for the PMT readout, combined with a CAT-like
sector trigger scheme
- Jan. 99
- First batches of mirrors arrive at MPIK
- Start series measurements of mirror characteristics at MPIK
- Dec. 98
- Letter of support from the President of the Republic of Namibia
- Nov. 98
- Visit to Namibia by a french/german H.E.S.S. delegation;
begin of negociations with the owners of the Farms Goellschau
- Offers of the Farms Goellschau and
Gamsberg in the Khomas Highland of Namibia to host the H.E.S.S.
- Contract for design of mount and dish awarded to SBP
- Sept. 98
- Contract for mirrors awarded to COMPAS and GALACTIKA
- July 98
- Campaign to measure atmospheric dust in Namibia
- Initiate bidding process for mirrors
- Feb. 98
- Proposal of the ``Smart Pixel'' concept for the modular
construction of the cameras and the trigger system
- Jan. 98
- H.E.S.S. collaboration established at Heidelberg meeting,
including MPIK Heidelberg, Humboldt Univ. Berlin, Univ. Bochum,
LSW Heidelberg, Univ. Kiel, Ecole Polytechnique, College de France,
Univ. Paris VI-VII, Saclay, Univ. della Basilicata and
INFN Rome, IAS-CNR Rome.
- Decision to give sites in the Gamsberg area of Namibia
- Dec. 97
- First visit to Namibia and South Africa to evaluate potential sites
- Sept. 97
- Decision for SBP design of mount and dish
- Ringberg Workshop
- Aug. 97
- Coast Steel design study delivered
- July 97
- SBP design study delivered
- Mar. 97
- H.E.S.S. Letter of Intent
- Feb. 97
- Visit to, and evaluation of Calar Alto site, Spain
- Jan. 97
- SBP design study initiated
- Dez. 96
- Vertex design study delivered
- Oct. 96
- Vertex design study for mount and dish initiated
Coast Steel design study initiated
- Feb. 96
- First design concepts for a new telescope system
- ESO/MPI-A survey of Gamsberg site in Namibia