Aphelion sun 05 July 2013
Aphelion sun 05 July 2013

Aphelion is when the Earth is at its most distant point in its elliptical orbit around the sun.  For 2013, that’s today, 5th July 2013.  This image was taken using standard equipment, a Skywatcher 200p telescope, Baader solar film and a Canon 1000D DSLR.

The clearest day yet and with corking sunspot activity on the suns surface, the photosphere.  The large dark central region of a sunspot, called umbra, is a cooler area of the sun’s gaseous surface by powerful magnetic fields.  Sunspot AR1785 is as wide as the Earth.  That sunspot and limb darkening show up quite well in in the white light image of the sun (top).  The image on the left is taken in hydrogen alpha, my first attempt using a webcam with the Coronado solar telescope slightly shows faculae around a sunspot and the faint line of a filament at the top right.  Quite difficult to image with this particular telescope as its known for having a “sweet spot” where focus or more accurately tuning is crucial.  I used an old Philips SPC900 webcam for this image.  A fast frame rate CCD camera (monochrome) like an Imaging Source DMK21 could make a huge difference to image quality.  Something I keep wanting to buy but keep putting off.


Nick Cook. Amateur astronomer, space, history, nerd, extreme dog walker, cat slave, severe tinnitus sufferer. 13.7 billion years in the making - not that much better for it.

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