Thursday, 21 August 2014

LBA aerials

KAIRA has 48 low-band antenna (LBA) aerials. These were designed by ASTRON (the Netherlands Foundation for Radio Astronomy). The arrangement of the aerials looks pretty random, but in actual fact it has been carefully chosen to give a good beam-pattern for the radio telescope. Each aerial comprises a steel grid which acts as a ground plane for the aerial. The post is PVC (starting to fade in places due to UV-light exposure) and the black cap at the top contains the low-noise amplifiers (LNAs) - one for each polarisation.

The wires that extend from the cap to the corners of the ground planes are the antenna wires. The form crossed inverted-V dipoles, giving good all-sky sensitivity. Actually the wire part only goes about halfway down. The lower part is either nylon line or elastic, which is used to hold the aerial in place.

Low-Band Antenna (LBA) at KAIRA. (Photo: D. McKay-Bukowski)

Wednesday, 20 August 2014

Ounas River

Today's photograph is dawn, seen over the Ounas River, not far from Kittila.

Ounas River, Lapland, Finland.

Tuesday, 19 August 2014

Mushroom harvest

Some of our readers may recall the great mushroom picking expedition of 2013. Well, this year, our Supreme Mushroom Leader (Lassi Roininen) set forth again on another epic journey (this time without lackeys to make a mess of things) and, once more, came back with a lovely mushroom harvest.

Mushrooms from the forest.

Of course, our regular readers will know the fate of any food produce brought to the EISCAT building at Tähtelä on a Sunday afternoon... home-made pizza!

Pizza done!

Not surprisingly, everyone was happy to have a piece or two. And, you must admit, mushrooms are rarely cooked fresher than this!

Nom. nom. nom.

Monday, 18 August 2014

KAIRA site buildings

I took this photograph during a recent trip to KAIRA. The structure on the left if the RF-container. note the large grey panel on the near-side... that is the cowling to protect the airconditioner from snow and ice. The timber structure on the right is the HBA cable mausoleum. This is where additional cable delay line length is placed. Normally on LOFAR systems, this is underground. However at KAIRA both the LBA and HBA arrays have above-ground housing for the extra delay lengths. The other raised building is the site office (known locally as the "barracks").

RF-container and HBA mausoleum, and then the site office. (Photo: D. McKay-Bukowski)

Sunday, 17 August 2014

An unexpected guest

The other day there was something banging and clattering outside my room. I couldn't figure out what was going on and I didn't spy anything directly outside the window. Then, there was a strange snorting noise. Really weird.

Anyway, curiosity got the better of me and I got up to go and have a look.

Easily startled... but hopefully not back in greater numbers. (Photo: D. McKay-Bukowski)

Don't stare at me like that! (Photo: D. McKay-Bukowski)

Friday, 15 August 2014

LOFAR Aerial Photos – Nançay

Another of the LOFAR sites has become visible in aerial imagery. The French site at Nançay can now be seen in Apple's Maps.app, which is supplied with iPhones and iPads. If you want to find it yourself, here are the co-ordinates: 47°22.54'N, 2°11.56'E, or go to Nançay and look for the large T-shaped antenna array north of the town. Under the left "arm" of the T, you'll find the LOFAR site.

Photo: Apple Maps.app.

Thursday, 14 August 2014

Sunlight on the EISCAT dish

Arriving back late at the observatory one evening I caught the late evening sun striking the 32m EISCAT dish. The photo doesn't really do it justice, but the colours and lighting were sublime.

The Sodankylä 32m EISCAT dish (Photo: D. McKay-Bukowski)