The OM is equipped with a filter wheel holding several optical elements that can be moved into the light path. These elements, which are described here, comprise not only filters, but also two grisms and a magnifier. The complete set of optical elements is collected in Tab. 14. Their arrangement on the OM filter wheel is indicated by the position number on the filter wheel. Sequences of exposures using different optical elements must always have increasing filter wheel position numbers. Observations with the three optical broad-band filters U, B and V, for example, must always be conducted in the order V, U and B (positions 1, 3 and 4).
 |
 |
| 0 | Blocked |
| 1 | V |
| 2 | Magnifier |
| 3 | U |
| 4 | B |
| 5 | White |
| 6 | Grism 2 (visible) |
| 7 | UVW1 |
| 8 | UVM2 |
| 9 | UVW2 |
| 10 | Grism 1 (UV) |