|Help and Advice|
|Transit of Mercury 2016|
|Giving long exposures on a digital camera|
|Photographing star trails|
|Predicting the ISS and other satellites|
|Using a mirror to view a partial eclipse|
|Simple Guide to Viewing the Space Station|
|Choosing a Telescope|
|Tips when projecting the Sun|
|Starting to Use Your Telescope|
|Imaging with a DSLR through the telescope|
|Buying a telescope for a child|
|Photographing a partial eclipse|
The recent large sunspot, AR2192, was not the largest sunspot group that has been seen on the Sun; there have been others that were larger.
The usual way of measuring the size of a sunspot group is to express the area it covers in "millionths". A sunspot that covers 1 millionth would cover 0.000001 times the area of the Sun's Earth-facing hemisphere. For a sunspot (or sunspot group) to be visible to the protected naked eye it must cover about 300 to 500 millionths or more (by comparison, the Earth would cover 169 millionths). This list shows all the sunspots/sunspot groups that have been visible since 1874 and were larger than AR2192.
|Year:||Month:||Day:||AR No.:||Sunspot Area (in millionths):|
|1947||April||3||14886||6132 (largest in recent history)|
Sources: Data taken from Spaceweather.com & Spaceweatherlive.com websites.