The solar activity is waning, but the sun still manage to produce some nice spots. Like these ones.
I haven’t been able to use my telescopes for a couple of months, but the Mercury transit couldn’t be missed. Back home after work I set up and began observations at 15:00 UT. I was treated with a clear blue sky and acceptable seeing. For the observation I used my trusted 10″ SkyWatcher dobsonian, masked down to 4″, and a 17 mm Baader Hyperion eyepiece (for 70x). I followed the transit for about an hour and a half. By that time the sun had dropped towards the horizon and the seeing deteriorated.
Not as impressive as the Venus transit a couple of years ago, I still found the slow progress of Mercury over the face of the sun fascinating to observe. The planet was small, very distinct (of course), and nicely framed by to sunspot groups: AR2542 the larger group at the bottom and AR2543 close to the center of the solar disc. The direction of Mercury’s movement was difficult to pinpoint, and might be a bit off.
I also tried to capture the event with my (handheld) cell phone. Below is the best of several tries.
During the last couple of days a new giant sunspot group has slowly marched across the sun. So far I have managed to make two sketches. The group has increased both in size and complexity over the days, and I have found it quite challenging to sketch.
The sketches below has been rotated to match the images from the Solar and Heliospheric Observatory.
The behemoth sunspot AR 2396 is slowly moving across the solar disc, arousing both sketchers and astro-photographers. So far I have managed to sketch it twice, and even if I find it difficult to estimate the size of sunspots, it seems to have grown from one day to the next. Do note that the difference in size between the sketches below does not primarily correspond to any physical developments, but rather to the scale used while sketching.
Edit: I managed to make a third sketch just as AR 2396 approached the limb. Inserted below.
The sketches below depicts AR 2371 and were made on 20 and 21 June 2015 respectively. I used my 10″ SkyWatcher (with a solar filter and masked down to 100 mm) and a Baader Hyperion 17 mm eyepiece for 70x. At both occasions the seeing was rather bad, and the group didn’t show any finer detail. Inserted to the right are the corresponding images from the Solar Dynamics Observatory showing the group to the upper left.
Edit: I had the opportunity to do a third sketch today (inserted at the bottom). Equipment as above.