Thursday 31 October 2013

The KAIRA ghost...

The 31st of October is celebrated in some parts of the world as All Hallows' Eve. It is of Celtic origin and finds it roots in the end-of-summer festivals of Samhain (Ireland), Calan Gaeaf (Wales), Kalan Goañv (Brittany) and Kalan Gwav (Cornwall). It was a time that marked the start of the dark-half of the month and the time that the spirits, dark elves and ghosts would re-enter the world. Folk would be fearful and make offerings to placate the beings from the otherworld.

These days, the commercialisation of Halloween has ruined any sense of wonder or mystery associated with this special time of the year. However, notwithstanding, we have a ghost tale for you to mark the occasion.

And it is a true story...

The KAIRA ghost

It is said that every observatory has a ghost. For anyone who has ever worked at one of these places, especially at night, it takes little imagination to realise the isolation, shadows and strange noises of the telescopes will play on the mind of anyone working there. A strange set of surroundings, in a remote place and, inevitably, with a complete lack of sleep will let the mind play tricks. Nasty tricks. Tricks that awake a primal fear that lies in us all... even the most hardened of scientists.

It is also said that anyone who has never seen or heard an unexplained phenomenon is unobservant. Certainly things can later be explained, but sooner or later, if you are aware of your surroundings, there will be an occasion where something catches your attention and reaches into the core of your psyche. Reaches deep. Very deep.

I have been working at telescopes now for *cough* years, and I have now seen two ghosts. The first took me completely by surprise and totally freaked me out. Even now as I type this I can feel my skin crawl. *shudder* But that was a long time ago.

Today's story is from this year. And it is from KAIRA.

At KAIRA we jokingly talk about the Uhrikivi stone. A stone that requires a blood sacrifice to be appeased. It started as a bit of a joke (having sliced myself open a few too many times during cable works), but with every visit there always seemed to be a nick or scratch or something. One drop. Just one.

So it was late one evening when the site was dark that this tale begins. The sun was long gone and the sky was dark, although perhaps not completely. The site itself was in darkness and I was making my way back from western edge of the High-Band Antenna (HBA) array. I had been checking the anchor lines on the covers and some had needed to be adjusted. In doing so, and in the gloom, I had accidentally run my hand along the timber snow barrier along one of the tiles. It was tile H78... but that is not important now...

... and, yes, there was a drop of blood.

I started thinking to myself about the Uhrikivi stone and wondering what the ancient folk must of thought in days long past. Perhaps I made a mistake. Maybe I let my imagination run a little too far.

However, I put the thoughts out of my mind, carried on with the checks, up along the south western edge of the HBA array and then turned the corner. For a moment, I lost my breathe. There, in the darkness, were two glowing eyes staring at me...

... red eyes.

Red glowing eyes in the direction of the RF-container, or maybe it was the site barracks, I'm not sure.

I stopped abruptly and stared into the darkness.

Deep red eyes. Blood red eyes. Burning in the night like glowing embers. Then they moved, wavered a bit and then blinked shut. The inky blackness returned.

I could feel a lump in my throat and became acutely aware of my surroundings. Everything was silent. I peered into the gloom by I couldn't see anything. No movement, no glowing eyes. I must have stood there for a minute or so, although it seemed like an hour. Then, just as I had calmed myself down and decided it was nothing,...

... the screaming started.

At first it was distant. I was not sure if it was my imagination or if it was real. I was starting to feel quite spooked and I tried to convince myself that it was the wind in the trees, or perhaps through the framesets of the HBA...

... but no.

The screaming stopped. I waited. Then, just as I was about to dismiss it, it started again. Nearer this time. It sounded like a child, the sort of crying not when they are upset or hungry or anything like that. It was more like a shriek. Shrieks of...

... pain.

By now I was convinced that it was real. Definitely real. This was not my imagination, but something physical and distinct. Of course, you might just think I am making this up. I can assure you that I am not. And, after the moment of terror passed, I even had the wits about me to get out my mobile telephone and for a moment, a brief moment, make a faint and noisy recording of the haunting sounds that I heard in the darkness on that bleak, lonely evening.

There are no images. But you can recreate the experience for yourself. Simply close your eyes. Feel the darkness and listen.

In the cold light of day, there is a good explanation for what I saw and heard. When surrounded by our familiar modern world we laugh at these primitive superstitions and silly beliefs. However at that moment, in that place, I felt a connection with what no doubt many ancestors would have felt in centuries long gone by, when the world was a wilder place and we were still but a small part of a more daunting and more unexplained universe. Uncertainty...

... fear.

Wednesday 30 October 2013

Science Camp cultural visit to 79 degrees North

Another report from Esa Turunen in the far north...

The morning of fourth day in the Finnish students "Space Weather Science Camp" in Longyearbyen finally gave us the starry skies and clear weather. This in Svalbard means at least -15 degrees C cold temperature and increasing chill factor with the ever blowing sea winds. Specially you could imagine the chill factor onboard a ship, such as the M/S Langøysund. This boat, with a staff of 4 persons, one of them a very competent international guide speaking several languages, took us on a cultural visit to Pyramiden. Pyramiden is an abandoned settlement at nearly 79 degrees north, once a lively coal mining town of 900 people, including whole families. While Longyearbyen still in 1970's only was a town of a few male mining workers, Pyramiden had a swimming and sports facility, cultural house with indoor basket ball court, theater and cinema, own hospital, farmed animals, school and children play grounds.

Today Pyramiden is inhabited normally only by 2 persons, and even they move away for the winter. There is a hotel, which offers services at some tourist season times and tourist visits are organized by boats from Longyerbyen. When the original inhabitants left the town, they only had 48 hours to collect their personal belongings and the whole town was emptied at once. The houses and rooms were left as they are. Today you can make a museum time trip to a complete small town of the Sovietunion time here. Some houses are even renovated, so that Pyramiden is slowly changing its face from a ghost town to a cultural heritage attraction in the far, far north.

The boat trip itself was an extraordinary arctic experience. Lunch was served as barbecue on the front deck, despite of the wind and freezing temperature. Vegetarians got their own icebergsalad plates, hot omelettes, salmon and naturally a taste of grilled whale meat was available, too. As sun painted the morning sky with golden colors in the east, pastel shades were seen allover the rest of the sky, above the sharp and layered mountain peaks, which are characteristic to Svalbard. The ship brought us near to the glacier Nordenskiöldbreen for the lunch break. As extra surprise for 2 minutes we could admire the fins of a few whales as they swam away from the boat. At Pyramiden we saw typical arctic animals at a very near distance. Two ptarmigans were eating seeds by one street and an arctic fox was searching for food near to the hotel building. They seemed to belong to the current inhabitants of the town letting us to photograph them at 10 m distance.
M/S Langøysund waiting four the students at
08:30 in Longyearbyen, ready for the trip to
Pyramiden. (Photo: E. Turunen)

Discussing space physics on the front deck
of M/S Langøysund. (Photo: E. Turunen)

Nordenskiöldbreen, a glacier named according to the
famous Finnish-Swedish arctic explorer, who
once was here, too. (Photo: E. Turunen)

Pyramiden, an abandoned ghost town at
nearly 79 degrees north. (Photo: E. Turunen)

The main square of Pyramiden, view from the cultural
house towards Nordenskiöldbreen. (Photo: E. Turunen)

The sun is above horizon but behind the mountains.
Skies are painted by pink and blue pastel
shades in Svalbard. Note the stunning geology
of these mountains. (Photo: E. Turunen)

Tuesday 29 October 2013

Bahir Dar school - Concluding remarks

After hectic weeks in Bahir Dar, two members of the KAIRA/SGO team are now back in Finland and the rest of the group will return by the weekend. During the visit, we ran a series of lectures on applied mathematics and space physics. In addition we had splinter sessions on various topics (riometry, radar installation etc.) and discussed the curricula of mathematics and physics education in Bahir Dar University. BDU is developing fast and expanding rapidly, hence the need for curriculum revision. Our Lappeenranta and Tampere colleagues are doing similar things with a number of East-African universities and thus we have a consortium project for  these efforts. You can find our project website at This project is funded by Ministry for Foreign Affairs of Finland and Centre for International Mobility (CIMO). Funding is greatly acknowledged!

The next Bahir Dar event will be held in October 2014 The dates are somewhat tentative. This event will be a quad-lateral effort with Ethiopian, Finnish, US and South-African colleagues. In addition, we have scheduled the second Inverse Problems Africa workshop for late 2015. It will be held in Kampala, Uganda. The International Symposium in Equatorial Aeronomy will be held in Bahir Dar around 2016. (If I remember correctly.) Thus lots of interesting events will take place in the region in the near future. Naturally we encourage all the colleagues to attend these events!

And below a large set of photos from Bahir Dar by Mikko Orispää! (Might be useful for people who are thinking to participate 2014 events!)

Bahir Dar mosque.

Market I

Market II

Market III

Kids playing.

The ultimate public transportation 'device' - the Bajaj!

Markku and Lassi walking to the University gate.

Bajaj driver and co-driver!

Workshop lunch in Lake Shore

Lunch again.

University monkey!

Bahir Dar University stadium, where the grandiose Ethiopia - Finland (4-2) football match took place.

Kids playing on the shore of Lake Tana.

Bajaj hassle!
Lads posing to the camera.

A nosy boat.

Bahir Dar avenues.

And some random flower.

Physics department.

Donkey - the local Toyota HiAce

Cooking and selling food...

Lassi before the film festival event.

And the cinema, where we watched Stanley Kubrick's film '2001: A Space Odyssey'

And yes, we did have enough room for the film audience....

Bunna mafelat - Coffee ceremony before the film.

Odours of Ethiopia...

And the coffee beans...

Monday 28 October 2013

Dual antenna passive radar interferometry

Last week I tested passive radar interferometry with two USRP N200 devices and new K&R filters (this could in theory be done also with thee rtlsdr dongles with a shared clock). Three channels were recorded: the transmit waveform with a directional antenna pointed towards the FM radio transmitter, and two SKA (Square Kilometer Array) prototype log periodic prototype antennas pointed towards zenith to record echoes. 

To analyze the signals, I performed deconvolution of the transmit waveform, and estimated a cross-spectrum between the two channels at each range gate. I then plotted the range-Doppler-intensity of the echoes, using hue to encode relative phase difference between antennas. The results mainly show airplanes moving about in the two antenna interferometer with a ~18 lambda spacing, but there are occasional specular meteor echoes too. The phase gives some idea of where the signal is arriving from, but there is still ambiguity that can only be resolved by adding more antennas.    


Here are some plots of some specular meteor trails that I spotted in the results:

Specular meteor echo at 200 km range.

Specular meteor echo at 150 km range.
Meteor at 240 km.
Meteor at 150 and 200 km.

Meteor at 110 km.

Meteor at 90 km

Meteor at 230 km.
Once we get more cables to the antennas, we should be able to start testing passive radar imaging and radio source calibration. There are already plenty more antennas awaiting cabling:

The rapid antenna field. The xmas tree like log period antennas are the SKA Cambridge prototype antennas, the loop is for HF, and the small white dome is the NASA space debris radar.

The ground clutter has been removed from the above pictures, to avoid self-noise. Out of curiosity, I also plotted that:
Ground clutter phase difference-range-time-intensity picture. The clutter phase difference is fairly stable, indicating that the ground clutter angle of arrival distribution is also fairly constant over time.  
The bottom line is that the 16 channel usrp receiver works fine for passive radar with the K&R filters to remove aliasing.

Update: added a picture of the antennas, and more meteor echoes. Fixed typos.

KAIRA HBA polarisation orientation

Within each High-Band Antenna (HBA) tile there are sixteen elements comprising a crossed bowtie antenna. These are in "cells" which can be rotated to different orientations depending on the layout of the array and its location in the world. Following some requests from observers we have drawn up the layout of the elements in our tile and made it available for distribution. The result is as follows:

The circle represents the rotating part of the cell. In the centre of that circle is a representation of the printed-circuit board with the amplifiers, etc. The four "blades" of the antennas are connected to this. Two F-type connectors at the bottom of the boards take the signal out to the tile summators (but also bring power and control into the unit).

Sunday 27 October 2013

Field of the Space Weather Science Camp

More from our intrepid KAIRA-reporter... Esa Turunen.

The field trip to Kjell Henriksen Observatory and EISCAT Svalbard Radar during the Longyearbyen Science Camp revealed how actual work in science is done. A vital part of research is getting your data, in this case using the highest quality ground-based instrumentation for Space Weather measurements. Professor Fred Sigernes welcomed the group at KHO with a comprehensive lecture about the the scientific quest for knowledge and understanding Nature's most beautiful light show, the Aurora Borealis, the Northern Lights. He also had a very special task after introducing all the fancy optical instruments of KHO. Longyearbyen as part of Svalbard archipelago belongs to the realm of a special protected animal: Ice bear. As KHO and ESR are located outside of Longyearbyen, 10 km out of the town on gently rolling slopes of a mountain, it is important to follow the all safety regulations. These include a need of a an armed guard when moving in the field anywhere outside of the town centre. While the students arrived to KHO by bus transfer, the 1 km distance between KHO and ESR was left for a snowy walk, in -15 C temperature and moderate northern mountain wind. Prof. Sigernes followed our group carrying his rifle, securing a safe walk down to the radar.

At ESR, after a Norwegian light lunch, consisting of a cheese baguette, bottled water and a fruit, we met the ESR Site Manager Halvard Boholm. He explained what the huge 42 and 32 meter antenna dishes are used for, and showed the technical and operational details of the incoherent scatter radar. Visiting the control room and the transmitter hall of the 1.5 megawatt radar is an impressing experience, very similar to visiting the underground facilities at large particle accelerators. Returning back to UNIS Dr. Noora Partamies once more went through yesterdays radar data in lecture hall and prepared everyone for the evening exercise: Hunt for aurora using your own camera. Unfortunately the skies did not clear up enough and the evening was mostly cloudy. We saw from instruments on web that faint aurora is visible south of Longyearbyen, but the main photograph of the evening session turned out to be a light painting, where students formed the letters of the word Longyearbyen in the air. They used the illumination from their mobile phone displays. After returning back to hotel, one of the students however persistently went out to check the skies. In the end he managed to get a photograph of a weak auroral arc in the horizon. The phenomenon was named the "Sakari Arc" accordingly.

ESR control room. (Photo: E. Turunen)

Lunch at the coffee room of ESR site. (Photo: E. Turunen)

Dr. Noora Partamies explaining variations of electron density profiles during the moderate aurora on Tuesday. (Photo: E. Turunen)

The student group photo in front of the fixed-pointing ESR 42m antenna. (Photo: E.Turunen)

Walking in the snow. Visibility during the 1 km walk from KHO to ESR was not really perfect, nor was the walk not too hot. A good start of an arctic action day at ESR. (Photo: E. Turunen)

ESR transmitter hall with the 1.5 megawatt transmitter. (Photo: E. Turunen)

Saturday 26 October 2013

Visit to EISCAT

This week the KAIRA observers have been at the EISCAT facility near Tromsø, Norway. This was to carry out observations of the ionosphere using both the UHF and VHF radars while KAIRA was also observing the same region. During the visit, we had an opportunity to tour some of the facilities, along with other visiting scientists who were there for their own experiments.

Visiting scientists touring the EISCAT facility. (Photo: M. Rietveld)