Tag Archives: Nebula

Deep Space Objects

While Deep Space Objects (DSOs) technically includes stars, it is generally about nebulae, galaxies, and star clusters. Most are small and dim, so a telescope is needed to see them. Others can be seen with modest magnification of binoculars or a small telescope. Initially I will limit this newsletter to those visible with the unaided eye, and eventually cover those that can be seen with some magnification. It is important to note that DSOs never appear as bright and colorful to the eye, even when using a amateur telescope, as they do in astrophotographs. This is because camera film (in days past) or sensors can gather light over much longer periods of time than can the human eye. Many of the brighter and more interesting DSOs were cataloged by Charles Messier in the 18th century. Messier objects are assigned an ‘M’ number.