The OM offers a possibility to change the instrument setup by inserting
a lens system - which is mounted on the filter wheel - into the light
path, extending the focal length of the telescope by a factor of 4. Thereby,
the pixel size (in angular units) and the size of the FOV for a given pixel
array can be reduced by a factor of 16. This leads to an in-memory pixel
size of
(0.125'')2. Using 
pixel binning, this translates
into the same size for the resulting image pixels. The magnifier thus
offers the user a chance to perform high-resolution, low-background
imaging with a small FOV.
One particular application of the magnifier that might be of interest to users is the avoidance of bright sources within the OM's FOV (cf. § 3.5.8).
Normally, when trying to perform very sensitive observations, one will want to use a filter with a high throughput, such as, e.g., the white light filter of the OM. The problem with bright sources in the field of view then is the danger of damaging the OM photocathode with their incident high photon flux. This is the reason why it is not possible to avoid such bright sources by just choosing a science window that will not read out the source's photons. Instead, the source must be kept out of the FOV so that it does not damage the photocathode. For field sources more than 5' away from the pointing position exactly this can be achieved by choosing the magnifier as the optical element in the lightpath, which reduces the size of the FOV. Since the magnifier has good throughput in the optical, its sensitivity is comparable to that of the white light filter. When using the magnifier, only the imaging scale is changed compared to ``normal'' observations with a filter. Thus, the magnifier can be used, in the standard fashion, with the default configurations introduced above (§ 3.5.3.1). In this fashion, bright sources at distances of order 5' from the target can be avoided while performing sensitive imaging of sources with a small extent (the OM FOV with the magnifier is about 4.25').