The Apochromat VSD 100 is a dream for astrophotographers: With an aperture ratio of f/3.8 it is very fast. That means you only need a relatively short exposure time. That not only means that it can capture more detail in dim objects during your observation night, but that you can do without guiding and get by with a lighter mount. With the Reducer for the VSD 100 you can even obtain an aperture ratio of f/3!
The optical system of the VSD 100 comprising five lenses ensures an even field of view and reduces chromatic aberrations. That provides a sharp image right up to the edge – even with a relatively wide aperture of 100 mm!
This example shot taken on 09.01.2016 shows the comet C/2013 US10 (Catalina).
To achieve a field of view that is sufficiently large, the Reducer is mounted on the VSD 100. 25 shots with an exposure of 30 seconds each were taken with a DSLR camera and added to this overall image. Thanks to the short exposure time, neither autoguiding nor an especially precise alignment were necessary.