Continuing my Space Scenery series…
There are several space telescopes observing the Sun and they are returning amazing data and, most importantly for the Space Scenery series, amazing images.
The Sun emits lights in all wavelengths – our eyes can only see one small range of wavelengths (i.e. visible light). The Solar Dynamics Observatory (SDO) has several instruments and is capable of capturing images in different wavelengths of light – it can see what our eyes can’t.
NASA make the images freely available – you can view or download images via the SDO Data Browser. For this post I downloaded images in all wavelengths of light that were captured by SDO on 1st March 2013 between the times 00:00:00 and 01:00:00. SDO takes about 4 or 5 images in each wavelength per hour – so in one hour it takes about 50-60 images.
I’ll start with an image in normal visible light (click to see the bigger version):
[Note that The Ångström is a unit of length equal to 10−10 m]
You can see a couple of sunspots – ‘cooler’ areas of 3000-4500°C that appear darker in contrast to the hotter surroundings at 6000°C – but apart from that, the Sun appears featureless.
All the action takes place at the wavelengths our eyes cannot see. If you place different filters over the cameras, you can capture only the light that can get through that filter. So, by using different filters you can see different features that are prominent at various wavelengths.
Rather than just present a series of images of the Sun in different wavelengths, I thought I’d combine the SDO images to form one multi-coloured image. Click to view the big (6 MB) image:
All these images were taken within 3 minutes of each other – so they practically match up. Notice the prominent feature in the leftmost ‘slice’ – it is emerging from the sunspot you can see in the 4500 Ångström image.
The SDO data website also provides composite images – images combining 3 of the wavelengths. I thought I’d include them in this post as they fit the “multi-coloured” theme of this post:
All images from SDO archive.
- Exploring The Sun with Helioviewer
- Exploring Sunspots and Coronal Loops with Helioviewer
- Space Scenery series