What is meant by “magnitude”?
Magnitude refers to the brightness of an astronomical body. Apparent magnitude 1 is exactly 100 times brighter than magnitude 6, each magnitude being about 2.5 times brighter than the next. Magnitudes brighter than 0 are minus figures, thus Sirius is -1.4, and the sun is -26.8. The faintest objects yet photographed are about magnitude +29.