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Fun in the Sun

I’ve been nosing around the Solar Dynamics Observatory site lately, and decided to have a play with some of their images. This NASA satellite was launched early last year, to study the Sun, and it has been returning astounding data ever since day 1 – astounding in both quantity and quality.

Like all NASA images, those from the SDO are in the public domain, so anyone can use them (with certain restrictions for commercial use). If you follow the link above, you’ll be at the main data page, which shows a series of images taken at different wavelengths. Most of these are in the far ultraviolet, and if you mouseover an image, it will show you the wavelength used, in Angstroms (10 Angstroms = 1 nanometre; visible light is around 4000-7000 Angstroms). Some of the most interesting and detailed images seem to be around 171 Angstroms, which, like most of the other UV images shown, is light from ionised iron (the image above shows the light from ionised helium.

The page updates regularly with the latest images, so you can see a progression in the Sun’s activity in just a short time.

The two images below have been combined into a 3D stereo pair (cross-eyed viewing); they were taken 12.5 hours apart, and the Sun’s rotation in that time generates a 3D baseline effect. Of course, the fine detail has changed in the meantime, so it’s not a perfect 3D, but you can see the Sun as both a round ball as well as a somewhat fluffy one! (Clicking on the image will bring up a large one.)

Below the first set of images on the NASA data page are some composite ones, made by combining three separate ones as a false colour RGB image (the upper set have been given arbitrary colours; being in the far ultraviolet, they have no colour that we can appreciate). You can make you own composites just by opening three different images, converting them to greyscale, and using a ‘combine channel’ function, using RGB channels (not sure what this will be called in PS, but it must be similar to PSP). Here are 3 of my attempts:



The first two are made from the same set of images, but with different channel selections. The possibilities aren’t quite endless, but I’m sure there are more creative folk than me out there, who could do something amazing with these images. Go to it! If nothing else, just be amazed by the appearance of the Sun in other than white light.

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