Friday, October 12, 2012

Eclipse 2012 - Corona photography project

Imaging setup - Borg 100ED refractor,
Nikon D300 camera, Astrotrac TT320
equatorial mount and Induro carbon fiber
tripod. (click for larger view)
This is the second part of my blog essay about the total solar eclipse of 2012. I'll be posting frequent updates on preparations and - once the journey starts - how our progress is going towards the ultimate goal of witnessing this spectacular event.

Besides being a hybrid tour guide / tourist I'll also be an astrophotographer. My project is to attempt medium-high resolution imaging of the inner Solar corona. To this end I'll be imaging with a plate scale of 2.4 arcseconds/pixel using a DSLR camera with a four inch f/6.4 refractor on an equatorial mount. These days most of my spare time goes into preparing this setup for action.

The plate scale, i.e. number of arcseconds pr. pixel is NOT the actual resolution of the final image. This can only be measured on real images and it is affected by many factors, such as optical imperfections, mechanical vibrations, tracking errors, atmospheric turbulence, etc. If all goes really well I'm hoping that the resolution of my setup will be around 3 pixels = 7 arcseconds. This isn't high resolution compared to planetary or deep sky imaging, but it is in the upper realm of corona imaging. Space based observatories are the only routine means for observations of the corona and the best of these (SOHO's LASCO instrument) have a resolution of only 20 arcseconds. The very best ground based images can reach 3-4 arcseconds but this requires equipment and skills that I do not have!
Simulated field of view of my setup.
(click for larger version)
In the next blog posts I will discuss the ongoing preparations, how friends are helping and field testing under the skies.

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