ASTRONOMY
not many other people have planned to look at.’ Tere has been some unexpected finds for
the ASAS-SN team. Last year the team observed an M-Dwarf – which is a type of low-mass, very common star – produce a solar flare in which they saw the star get 4,000 times brighter. ‘Tis was the biggest flare ever seen and it happened within the first few months of our operation,’ Stanek said. In January, the team observed what is known as
a tidal disruption event, which is where the central black hole swallows a star. ‘A handful of these have been seen before, but we managed to capture one just a few months into our operation. It was also the closest one yet. Tis was very encouraging because it showed how successful observing the entire sky is already producing more than we expected. ‘When you look at our images, the public might
be a little disappointed; what you seen is a bunch of pixels and one gets a bit brighter. Our system notices the change and then lets us know that we should take a closer look at the region. Aſter the system alerts us to an area, we use much bigger telescopes to investigate. So this is a very valuable thing; it’s essentially a recon mission.’ Te team observed an 11 magnitude supernova
event that was very bright. Tis meant amateur astronomers could focus in on the event and make observations because they are so easy to see. ‘We are the feeder to a great number of people, telling them where to look,’ Stanek added.
Meteorites hitting the moon Te use of amateur astronomers to help collect data is common and projects such as ASAS-SN put as much information into the public domain as possible. Tierry Legault is one such amateur and has had asteroids named aſter him; his images have been published in national and international newspapers, and received the Marius Jacquemetton award for photographic works from the Société Astronomique de France. He explained the relationship between amateurs
and professionals: ‘Amateurs offer time and numbers. Professional means are much more powerful, but they are very few and can’t satisfy all astrophysicists’ demands or needs.’ A good example is lunar impact surveys,
observations of meteorites hitting the surface of the moon. Telescopes for viewing these don’t need to be large, but the events are rare, so surveying the moon continuously is necessary to record the number of impacts taking place. Legault has taken a variety of different images,
including the first and only amateur photo of a spacewalk. He explained: ‘I captured it with the same technique as planetary imaging – in video, at a focal length about seven metres – but with a specially modified motorised mount and soſtware
ASASSN-14ae images, referred to as a very luminous transient; obtained in January 2013 from Hawaii
that is able to automatically track satellites at high speed. It’s almost unique in the world and needed two years of development and testing.’ He explained that techniques are very different
between long-exposure for deep-sky and multi- frame video acquisition for the planets, ‘as different as photography of lions in Africa and sharks in the Pacific’. Tey differ in telescopes, focal lengths, cameras and also processing techniques.
This was the biggest flare
ever seen and it happened within the first few months of our operation
To capture the images, Legault uses several
different cameras: Canon and Sony DSLR for nightscapes, lunar quarters, and deep-sky images; astronomical monochrome video cameras for the planets, the Sun and lunar close-ups; and a monochrome CCD camera with filter wheel for deep-sky objects. Legault said: ‘Amateurs use safe solar filters,
some of them are cheap and others are much more expensive, ranging from €1,000 to several thousand euros, but show the solar prominences and flares.’ One of Legault’s most recognisable images is of the Atlantis shuttle and the International
28 Imaging and Machine Vision Europe • December 2014/January 2015
Space Station passing across the sun. Legault said: ‘Capturing the image in front of the Sun is easier than at night; you have to calculate the place and time of visibility, point the camera at the Sun and wait for the passage. Tis kind of event lasts less than one second, so with a DSLR you need to be very reactive and have a very accurate clock. I used a radio-synchronised watch for the ISS pass, but now I use a specially made GPS control box that triggers the camera automatically at a chosen time, because GPS modules are able to output an extremely precise time signal.’ Both Stanek and Legault said that they needed
good cameras that were affordable. Stanek said: ‘It’s very hard to get funding for science in the USA at the moment. We were given the initial funding from the National Science Foundation to start the project, but we just can’t get any more money. Tis is very frustrating as it seems that the system is working great.’ However, now the team at Ohio is collecting
data on half of the observed supernova, which Stanek hopes will help with the funding. He added: ‘One of these events we detected has been picked up by amateur astronomers, who in fact have bigger telescopes than we do. Tey have now been observing it for four months and there are 23,000 observations of a cataclysmic variable, and again, we just told them there is something bright in the sky and they take over from there.’ O
@imveurope
www.imveurope.com
Ohio State University
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48