The BT-Atlas images show objects which have apparent magnitudes between 18 and 21. So, what you see as a diffuse patch of light in the largest amateur telescopes are revealed in great detail in images in the BT-Atlas. The Universe’s diversity of forms is clearly shown here. Using the BT-Atlas is like taking a long and fascinating journey through the cosmos.
An important aspect of the BT-Atlas is the great number of galaxies photographed and the high limiting magnitude. This makes the BT-Atlas a convenient reference base for supernova research up to magnitude 19.
Finally, the BT-Atlas shows what can be observed with a telescope of moderate size (50-1000mm) coupled with a CCD camera. Astrophotographers will find numerous comparative examples in this catalogue.
The full BT-Atlas can be downloaded from http://www.deverchere.com/astronomie/catalogs/BT.zip. Many thanks to Christian Buil to give free access to the BT-Atlas catalogue.