Monday 2 March 2015
Solar Eclipse 20th March 2015
Tietoa Suomeksi: https://www.ursa.fi/index.php?id=6946.
On 20th March, 2015, there will be a solar eclipse in the Arctic. It can be seen as a total eclipse on Farøer and on Svalbard – weather permitting. In Sodankylä, at the maximum of the eclipse, the moon will cover 90.1% of the Sun. The eclipse will start at 11:08 h, reach the maximum at 12:13 h, and end at 13:18 h (as computed using NASA GSFC's Fred Espenak's "Java Solar Eclipse Explorer"). There's also a map available.
At SGO, we are working on a live webcasting project of the eclipse. The photo above was taken to test the equipment on 4th February, 2015, at the University of Oulu's Oulanka Research Station. Unfortunately a thin layer of clouds made focusing difficult.
However, some small sunspots are clearly visible, and they have been verified against a visible-light image from the SOHO spacecraft.
The setup will be as follows: a full-frame Canon EOS 6D will be tethered to a MacBook, and fitted with a 2x converter as well as a Tamron f/5.6 200-400 mm zoom lens giving an image of the Sun of a bit over 1000x1000 pixels. Most importantly, the lens opening facing the Sun will be covered with "AstroSolar" folio, which in Finland you can buy, e.g., here.
NOTE: Do not look at the Sun without this folio! If you intend to use welding goggles, make sure they are at least factor 14 or darker (according to the URSA Astronomical Association)! The sunlight can destroy your eyes, and you won't notice it at the time of observation, but only afterwards.
We plan on taking photos during the eclipse as fast as possible, but we will have to adjust the pointing direction of the camera ever so often, since the Sun moves fast across the field of view due to Earth's rotation.
Thus today, I wrote a software, which will automagically find the Sun in the camera's RAW file, centre on it, cut it out at full resolution 1500x1500 pixels, place the time stamp and copyright information on it, and push it out to the web (see photo above, click to enlarge). There's a lot more information on this process over on my own blog.
The address, you ask? Not decided yet, but of course we'll link it from our front page at www.sgo.fi and from this blog.
Now, all we need is clear skies! Keep fingers cross that we'll find it not too far from Sodankylä!
Text and photo: Thomas Ulich.