Michael Gilmer - Member of the Meteoritical Society & Collector of Falling Stars.
☄ ⒼⒶⓁⒶⒸⓉⒾⒸ ⓈⓉⓄⓃⒺ - www.galactic-stone.com
Quote:Take the example of a DSO listed as visual mag 7. If the object is 10'x10' then it has an area of 100 sq arcmin. The light would be spread over an area 100x greaater than the visual magnitude measurement. It would be 100x fainter. A light difference of 100x is 5 magnitudes so the Surface brightness of this object would be Sb = 7+5 = mag 12.0. edz