AR 10570, 2004/3/9

I observed AR 10570 on Tuesday at 20:15 UT. As seen through my Celestron C4.5 Newtonian at 36 and 72x this large sunspot (~10 Earth diameters) had a prominent, tadpole-shaped umbra. It was easily visible without magnification through my Mylar full aperture filter and polymer solar eclipse shades. I had a look at the sunspot at prime focus as well.

Dave Mitsky

Dave,

I just went out and observed the large sunspot. Often, for naked eye sunspots, I look first thru my binoculars to see where to look on the Sun's surface. This one didn't need any help, very prominent and basically in the center.

Some quick "Googling" led me to believe that sunspots get as large as 30,000 miles. Your approximation of 10 Earth diameters would be much larger than that. Have you seen larger ones than this one?