Lights Above

During the night of 31st January and 1st February 2017, Northern Lights were visible all night – despite a few thin clouds – above large parts of Northern Finland and Scandinavia. My photos from that night were published today in Finland's largest newpaper "Helsingin sanomat" in print as well as online: "Revontulet sykkivät mystisesti". The article tells about the current research collaboration between Sodankylä Geophysical Observatory and a few Japanese research institutes to study so-called "pulsating aurora", which refers to flickering patches of aurora.

Recently, I built a small camera system, which is able to take photos continuously for a long time. During said night, the camera was pointing almost straight up resulting in a short time-lapse film of about one minute duration. The film is composed of images taken over 9 hours at a rate of four photos per minute, and it is linked from the article mentioned above. In the video you can see several distinct shapes of pulsating aurora drifting through the image and flickering at the same time.

The camera was pointing in a direction of 75° elevation above the southern horizon to capture the auroral corona. The corona can be observed when the northern lights are almost directly overhead and one can thus look into the auroral arc or curtain. From this point of view it looks as if all rays of the aurora come from the same point in space. In reality, however, the rays are parallel, and the corona is a result of perspective. The same effect makes a long, straight road appear to become narrower in the distance, which of course it not the case.

The photo above, taken by Eric Donovan of University of Calgary, Canada, with a fish-eye lens, illustrates the perspective effect of the corona. The trees seem to grow towards a single point in the sky, but they are parallel in reality. Thanks to Eric for allowing me to use his photo!

You can find some more films of the Northern Lights of that night on the blog of the Sodankylä Geophysical Observatory (SGO). There's the film from the scientific all-sky camera, a two-camera composition by our friends from Site-Eye Ltd, UK, as well as an impressive fish-eye footage by SGO's Esa Turunen of early-morning pulsating aurora. Have a look!

Film and text: @2017 by Thomas Ulich.

Pan-Lapse Film

In late June, I went to Kilpisjärvi on a service mission to Finland's largest radio telescope, the Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA), which was built there by our institute, the Sodankylä Geophysical Observatory. The first thing I did upon arrival, was to place a GoPro time-lapse camera on an egg timer, in order to make a full 360° panoramic time-lapse film (YouTube).

Do you want to know how I did it? Then read on...

The GoPro cameras (Hero 2 above) have excellent optics for what they are, since they have a fixed focal length (no zoom) and also have fixed focus. Thus the extreme wide-angle lens needs to do only one thing and is optimised for that. Also, the GoPros have a built in time-lapse mode, i.e. they can take 11MP or 5MP images at a number of set intervals between half a second and one minute.

The cheapest way to make rotating time-lapse films is to mount the camera on a cheap (about 4€ or so) IKEA egg timer. The timers do a full 360° rotation in one hour, which is a good duration for a time-lapse. The only negative point is that they can only rotate in one direction (unless turned upside down).

For the film above, I programmed the camera to take a photo every 10 seconds, and set the timer to 60 minutes. Thus the camera was set to take one image per one degree of rotation. Rather arbitrarily, I decided then to use these images to stitch them together to 360° panoramas by using twelve 30° sections. These sections are indicated by the grey lines in the image at the top. Thus I needed to take every 30th image and see how much they overlap, and cut away the overlapping parts in order to have only the 30° centre sections. Then I stitched the 12 images together, 30 images apart, leading to a 360° view.

Now, since the camera took a photo for every degree of rotation, I made 360 different panoramas, each shifted by one degree with respected to the previous. These were then combined into a full panoramic time-lapse film, also called a pan-lapse film.

If you look carefully when watching the film (e.g. look at the clouds), you will see that the same bit of film repeats in every pane and migrates from left to right through all panes. In other words, every pane is a 30-image time-lapse film, repeated through all twelve panes, and thereby making up a film of 360 frames. The film looks really nice when put on loop, but this is unfortunately not possible on YouTube.

There are a few other games one can play with this set of images, so watch this space!

By the way, I got the idea of pan-lapse films from Ken Murphy of Murphlab, please visit his site for this and other exciting time-lapse projects.

Photos and time-lapse film: Thomas Ulich.

Another blog post was published about this on the KAIRA blog today.

Building a play house

Finally, the play house project is taking shape. We bought a kit in late May, and began by surveying the location. We used concrete tiles as foundations, and it is very important to get all tiles exactly to the correct height, or otherwise the log construction will be skewed. We also put down a large sheet of geotextile to prevent vegetation from growing under the house.

The next step was to put down five foundation beams of wood, and the first layer of logs on top of that. Here, again, it is very important to have everything level, and to be absolutely sure that both diagonals are of the same length, or otherwise the house will not have right angles and things like window and door won't fit properly. So it takes ages to do all the preparations, but after that it's great fun to see the house grow — a process that we have filmed with our GoPro Hero 2 camera at one image per 5 seconds.

Have a look at the resulting time-lapse film, which is just over a minute long. Enjoy!

The final photo above shows what it looks like now. The cargo lashings inside are needed, because despite all accuracy with getting everything aligned just right, wood is a natural material and everything was slightly off direction and needed careful nudging into the right place.

Day 70: Painting Our House

This summer we have finally began to paint Our House. The weather this summer has been very variable, and bad weather and weekends seem to be highly correlated. Thus the progress is slow, but it's still looking good after only three days on the job.

On Day 68, the vertical columns and the horizontal beam under the roof were primed, and parts of the railing got their first coat of paint.

Almost at the end of Day 69, large parts of the western face of the house had received the first coat of red paint. Finally the final look became apparent: the classic combination of dark red paint for the walls, and white for the window frames.

The factory name of the colour scheme we chose for our house reflects just how traditional these colours are: "Mummola" ("granny's house"). The colours are Tikkurila 526X (red) and 603X (white).

Today (Day 70), we painted the lower part of the south face of the house, which turned out to be a somewhat tedious job, since there are three narrow sections with horizontal panels between windows, door, and at the corner.

We had a GoPro Hero 2 taking photos every 10 seconds during painting and made a short time-lapse film of it. The above image is a composite of the first and last images of the time-lapse sequence.

Finally, here's a photo of what it looks like now while writing this blog post. The gable as well as all wooden panels under the roof overhangs will have to wait until we have rented a cherry picker in order to work safely and efficiently.

Aurora: A Time-Lapse of Tonight's Lights

Tonight the Northern Lights appeared early above Sodankylä. The western horizon wasn't even completely dark yet. Here is a short (1 min) time-lapse film spanning two hours of observation with the All-Sky Camera of the Sodankylä Geophysical Observatory (SGO), Sodankylä, Finland.

The film, taken on 1st March 2013, begins at 1700 UTC (1900 EET) and ends at 1900 UTC (2100 EET).

UPDATE: All of this great night in one time-lapse film!

The all-sky camera uses a fish-eye lens with 180° field of view pointing vertically up. It takes grey-scale images through filters of green, blue and red. The green image is taken every 20 seconds, the red and blue images are taken once per minute. These images are then overlaid to make an RGB (false-)colour image. The blue and red images are recycled to cover those green frames, for which there's no red or blue data. This sometimes results in blue lights being out of place. But this is a small price to pay for the overall colour effect.

Enjoy!

Day 12: House Deployed

Today was the big day: Our House, which we spotted already last night parked up in front of a service station in the village, was deployed onto its foundations. Work began with the arrival of a large crane, and the first lorry with a house module showed up at 08:00 h. Another lorry arrived shortly afterwards.

The first module to be deployed contained the geothermal heat pump and hot water reservoir, and therefore it took some time to get the pipes fed into it before lowering it into its final location. Also, precisely lining up the first module is more difficult, the later modules are just placed a given distance from the first.

After the arrival of the second module, the plastic covers were removed and Our House revealed its interior for the first time. At the same time, a class of construction students from the local Lapland Vocational College showed up in order to see the construction process live.

There was a break, because the lorries had to return to their trailers, where another crane moved the other two house modules onto the lorries. This became necessary, because the dirt road to Our House has a narrow right-angle bend, and the site was out of reach of the trailers. Soon these modules arrived and were lifted onto the foundations. By lunch time, the house looked complete, with only the roof missing.

Another lorry arrived and brought all kinds of smaller elements, which are needed to complete the house. These include the steps leading up to the entrance doors, the small roof above the back door, the front porch floor, and the triangles for the roof. Nice to see the stairs, I guess there's no doubt who lives here...

It took less than an hour to put up all the roof triangles, plus another hour or so for the outer wall triangles at both ends of the building, which was completed only after dark and therefore above is the intermediate stage.

As one can guess from the photos, the weather was stunning again. Blue skies, a great sunrise and sunset, at temperatures of only –20°C, which is rather warm for blue-skies conditions in January. However, the registration plate of the crane looked very appropriate for these Arctic conditions.

A summary of the today's action is available as a time-lapse film, taken with a GoPro camera at one  photo per 5 seconds from 08:15 h to 16:15 h resulting in a short film of 3'30" duration (the lunch break cut out). Enjoy!