How to observe and photograph sunspots
Sunspots are regions on the sun on which the surface temperature is slightly lower. These regions emit less visible energy and from earth they look as dark spots. When looking at the sun with proper eye protection (glasses which are suitable for solar eclipse) the spots are clearly seen.
Sunspots are regions on the sun on which the surface temperature is slightly lower. These regions emit less visible energy and from earth they look as dark spots. When looking at the sun with proper eye protection (glasses which are suitable for solar eclipse) the spots are clearly seen.
Warning: Looking directly at the sun, or photographing it without protection is dangerous and can cause permanent eye damage.
This article focuses on how to photograph sunspots. I've used a regular camera with 35X zoom and a special sun-blocking filter which blocks 99.99% of the sun rays (and also blocks UV and IR radiation). Photographing sunspots requires using a dedicated filter, it is not possible to improvise and use for example an exposed films for this purpose!
The spots can be seen easily. Looking through a telescope (again, a proper and dedicated filter is a must, using a telescope focuses the sun's energy into a single spot and using a non-proper filter will lead to immediate and permanent damage to your eye) will show even finer details, while looking through a special solar telescope will show details on the sun limb as well.
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| Sunspot AR1429 6-Mar-2013 morning and evening |
The spots can be seen easily. Looking through a telescope (again, a proper and dedicated filter is a must, using a telescope focuses the sun's energy into a single spot and using a non-proper filter will lead to immediate and permanent damage to your eye) will show even finer details, while looking through a special solar telescope will show details on the sun limb as well.
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| Sunspot |
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| Sunspot |
Both pictures show the same sunspots (sunspots are officially numbered and these two are 1203 and 1204 in case you wonder). The first photo was taken in the morning and the second just before sunset, and you can see that the location of the sunspots is very different. Why is this? It is not due to the daily movement of the sun (actually it is the earth which moves). It is also not due to the rotation of the sun around its axis (the sun rotates around its axis, and this rotation changes the location of the spots, however, the change is visible after a day or two and not just after several hours). The reason is simply the rotation of earth around its axis. To further explain this, look below at the same photos as above, only now I have drawn in the sun's axis. You will see that the spots are in the same place, relative to the axis, and what has changed is the angle at which we, on earth, observe the sun.
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| Same sunspots in Sunrise (right) and Sunset (left) |
To summarize the issue, please watch the following video.
For further reading
How to observe and photograph sunspots
How to observe and photograph sunspots
