Thursday, July 29, 2010

Solar observations

Having a few days between returning from vacation (see the previous posts) and my return to work, I have had a chance to get back to some regular solar observing.  The days are quite humid right now and the window to observe is quite brief.  The overnight cloud cover seems to disappear about 8:00 AM and by 10:00 the atmosphere is already revving up for some afternoon showers.  Or so we hope...

I observed the sun in hydrogen alpha both yesterday and today and was able to make sketches both days.  You will see that the activity is very similar from yesterday to today, with the features moving a bit to the west from one day to the next.  (Note that my North and West compass points are estimations, and not actual measurements).

July 28, 2010 ~ 1720 UT
July 29, 2010 ~ 1540 UT

Active Region (AR) 11089 is decaying as it approaches the southwestern limb, but we are fortunate to have AR 11092 coming around in the northeast.  In fact, this region was just numbered today.  Within 11092, a strong sunspot has developed, although observing in hydrogen alpha does not show the spot with any detail. There are many dark fibrils within and around the region and hopefully it will develop further.  While there are a few dark filaments in the northern hemisphere, there is a surprising lack of prominences on the limb.  The Picture to the right is from the Solar Dynamics Observatory's Atmospheric Imaging Assembly which is now posting real time solar data.  The picture is reversed est to west from my sketches.  In it, you can see the active regions and some of the filament structure that I observed in hydrogen alpha.  

Jim Ferreira of Livermore, CA took this impressive photo sequence of an eruptive prominence just before sunset yesterday.  Click on the image for the full size!  Jim is an accomplished astrophotographer and I would recommend you visit his website by clicking on his name above.  He uses Stellarvue telescopes for much of his work, which is the same company that produced my 90mm triplet refractor and two of my previous scopes.

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