Onsala’s LOFAR station: ready for the universe


We now have a finished field of LBA antennas and the station is already complete. Leif will doubtless update with the facts and figures. In the meantime, this is a picture I took yesterday afternoon of the new LBA field in the afternoon sunshine under a clear blue sky. The new header picture shows both the LBA and HBA arrays.

Next we have to make sure that everything is working. A team from ASTRON i the Netherlands will visit sometime after mid-August to verify the installation. That’s when we’ll get our ‘first light’: an image of whole northern sky made from cross-correlation signals from all the antennas.

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Installation Week #4

 

HBA field is finally installed, last tile placed June 22 2011.
All the tools have been sent to the next installation site,
which starts a week from now at Kilpisjärvi, Finland.

All LBA meches have been placed, and 69 LBA antennas is erected.
The station is now moose proof, with a two meter high fence surrounding the area.

Team picture from the last day of HBA installation (June 22 2011)

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Installation Week #3

Photo: Leif Helldner

73 tiles installed at the end of week 24 (15 June 2011)

73 tiles installed, 24 more to go next week
192 markers positioned for LBA antennas
47 LBA meshes placed and anchored
Four LBA antennas erected
The fence installation have started, 
and now two meter high fence poles is surrounding the area

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Installation Week #2

12 trucks with total of 49 tiles and lids have been delivered so far,
39 tiles is installed and 10 in storage for next week,
Thursday we had rain and high wind speeds and managed only to place one tile,
we compensated for it on Friday by placing 15 tiles!
Calculated tile rate is 8 per day, so we are still on track!
 
The container installation team from ASTRON successfully installed all equipment and cables.
 
The LBA surface have been accepted and the contractor has completed the ground work and left us.
 
On Monday four summer-workers will be added to our installation staff, they will help us out until the end of LBA installation.
 
The fence installator will arrive on Monday, why we have to move our equipment and work-shed inside the fence area.

39 tiles on place (June 10 2011)

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Onsala’s first LOFAR antennas pass the moose test


Daniel Johansson making sure the
HBA tile lid is on right.

Mooseprint in the forest next to the field

The Onsala LOFAR station has its first antennas in place. 27 of the station’s 96 high-frequency antenna tiles arrived by truck from the Netherlands, and then transported by tractor, fork-lift (an Onsala speciality), crane and finally hand to their place on the HBA chessboard.

– We’re right on schedule. The plan was to install eight tiles a day and we’re keeping to that, says Leif Helldner.

At the weekend the field had a visit from one of its more important neighbours: a moose.

– It walked round past the HBA tiles and then right over the LBA field, Leif tells me.

It’ll be the last time a moose gets that close to the LOFAR antennas. In a few days Leif’s team will be putting up a mooseproof and deerproof fence around the site. We can’t be sure that our four-legged neighbours are as interested in science as we are.


The Onsala HBA transporter, specially designed for the new antennas in their polystyrene flatpacks.

Lifting the 27th HBA tile into place…

…ready for Karl-Åke Johansson and Lars Pettersson to check the cable connections.
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Installation Week #1

Delivery of tiles and lids have continued, six trucks have been sucessfully unloaded so far
20 tiles with lids is now stored and secured under tarpaulins at the site.
Cords with over thousand bowline knots tied to anchors
860 meters fleece is nailed down along the antenna alleys
520 ground anchors pounded and secured 60 cm down in the ground
Temporary plywood road is buildt
The crane placed at first installation position
Platform for unfolding mounted
First HBA antenna placed

The surface on LBA field is leveled and finished,
acceptance measurements will be carried out on Wednesday the 8th.
Everything is going according to plan!!

Part of the installation team, finished with tile one (June 01 2011)

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Installation Countdown…

The latest weeks have been very intense with preparations prior the LOFAR installation.

The HBA surface is now accepted and handed over to OSO and the first transports with installation tools and HBA-tiles have been delivered.
A team of total twenty LOFAR colleagues stands prepared awaiting the starting signal.

HBA field during cable rerouting

About three-quarters of the LBA field is now re-filled

First transport unloaded, all went well despite wind speeds over 15 m/s

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LOFAR antenna visits the Science Festival in Göteborg

The Göteborg Science Festival (www.vetenskapsfestivalen.se) is in full swing. Onsala Space Observatory is running a number of events at the festival. As part of the fun, we have a specially-built model LBA antenna which now has pride of place at the main festival centre in central Göteborg. The picture was taken just after the antenna was set up – by Lasse Wennerbäck (the man behind its construction) and Lars Eriksson and me. Installing took about 5 minutes, and the first conversation with an interested festival visitor came immediately afterwards. The antenna itself isn’t so beautiful, but it feels big. The thought of its 5000 friends in the whole of LOFAR makes the scale of the network easy to grasp – and easy to be wowed by.

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Fieldwork and photography, May 5


Wednesday at the Onsala LOFAR field was sunny and productive.
Astronomy PhD student Haukur Sigurðarson did his stint working on the field and took along his camera.
– I wanted to get an overview of the whole field, and just take pictures of people at work, he says.

Haukur explains that after laying the cables on the LBA antennas’ part of the field, he worked at covering the cables so that they don’t get damaged when the topsoil is returned.
– Shovelling sand for several hours was quite hard work. But it’s good to get the exercise.
Leif Helldner is pleased with progress.
– It went like clockwork! All cables laid, 36680 metres!, he says.

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Snow, snakes and 19 kilometres of cable

Station construction works better in good weather. Tuesday’s cold and wet conditions made the cables much harder to handle, reports Leif Helldner, and made it tough to keep up last week’s impressive pace. By Friday the team had rolled out over 19 kilometres of cable and on Monday 36 LBA cable pairs were set out. Fortunately today SMHI predicts nothing but sunshine for Onsala, so our new header picture (taken on April 29, see above!) gives you a better idea of how things look. Credit for photos: Onsala Space Observatory/Leif Helldner.

Tuesday’s snowstorm over the LBA field.

A picture from Friday. Beyond the LBA field you can see the 20-meter Onsala telescope radome.

A local adder slithered by to see what all the fuss was about.

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