Well, just by chance this week I scanned the SoHO smart phone app, and it showed a couple of sunspots. Wow, this was pretty unusual since I had not seen any spots at all for the last several weeks I looked.
Here is the SoHO smart phone image, from Saturday morning, showing at least two sunspots.
|Two visible sunspots (Source: NASA via SoHO app)|
This was pretty neat because we have not had too many sunspots during this normal quiet period in the sun's solar cycle. Remember that sun is also a variable star and seems to vary in brightness and number of sunspots on an eleven year cycle. Earthsky.org website has a lot of information and graphs of sunspot activity. In this screenshot below, you can see the eleven year cycle, as observed and predicted by various solar models. This year is the end of cycle 24 and the end of the cycle is the time when few sunspots are observed.
|Observed and Predicted Sunspot Cycles (Source: www.earthsky.org)|
So, I wanted to go out and get some DSLR images of the sun, but the clouds were not cooperating. I finally just had to snap one photo before the sun was total covered by the clouds. This single image was taken with 300mm telephoto lens, but doesn't seem to show any sunspots with all the clouds in the way. Afterwords, even though I wanted ISO of about 400, I found I had left the ISO 1600, from the previous nighttime observing and have to chalk this up as another lesson: Check your ISO setting each new observing session!
|Nope, can't see the sunspots through the clouds, 300mm cropped, 1/500 second (Source: Palmia Observatory)|
The rest of the day was even more cloudy. The previous photo was at least taken when I could see my shadow, but now the clouds just stayed around and no shadows. Even after waiting several hours, this iPhone image tells the sad story of the clouds getting in the way.
|Nope, the clouds were always in the way of observing any sunspots (Source: Palmia Observatory)|
Ok, we had more days of cloudy daytime skies, even though nighttime skies seemed to be much clearer. We finally had to wait till Monday morning before the clouds had moved out of the area. Now the SoHO app shows just one plainly visible sunspot. But if you look more closely at the screenshot, you can see another sunspot right next to the more visible one. When you compare the Saturday screenshot to the Monday screenshot, you can also see how the sunspots have rotated across the solar disk
Ideally, the best time to take a photo of the sun is when it is higher up in the sky. But, I was in a hurry with other meetings to get to today, so an early morning (just after 8 am) shot was all I could get scheduled. The sunspot in this image is in the same relative location as in the previous screenshot.
|One dim little sunspot starts to show up in 300mm, 1/125 second image (Source: Palmia Observatory)|
Ok, so even in this quiet period of the sun, a sunspot still shows up every now and again and we can quickly go outside with just a DSLR and take a shot. Now we could get out the longer focal length, 600 mm telephoto lens, and maybe even stack images to bring more detail of the sunspot, but this lazy astronomer wannabe leaves that to others. Maybe some of you, with longer focal lengths and skill in stacking images, or even better choices of ISO and exposure, can bring out a little more detail of the sunspots.
Until next time,