Focal Reducer/Field Flattener for the new Stellarvue SV80A Doublet Apo. This IS NOT for the SV80ST Triplet.
This reducer/flattener is optimized for our SV80 Access doublet lens. The flattener inserts into the 2" focuser. The 0.8X focal reduction converts the 80 mm f-7 into an f-5.6 with a focal length of 448 mm.
This reducer/flattener has a standard 42 mm filter thread. Standard 2" filters can be added to the reducer/flattener when imaging. The backfocus of the unit is 55 mm. Since a DSLR with t-ring has a 55 mm backfocus, plug the reducer/flattener into the focuser and then thread on the camera/t-ring to the flattener as shown below.
If you are using a CCD camera, an additional set of extension tubes may be needed depending on the backfocus of the camera. You need to know how much distance there is between the cameras T-thread and the ccd chip. It is important that the distance from the back of the field flattener to the chip be maintained at 55 mm. If the ccd camera has a backfocus of only 35 mm, a 20 mm extension will be needed. See the example below.
In this example the camera had a 35 mm backfocus so a 20 mm extension tube was needed. It threads in between the back of the field flattener/reducer and the camera as shown. Please call us and we can assist you in getting the exact adapters for your particular camera.
In this case the extension tube must be a standard t-thread (M42 X.75). Our selection of 42 mm extension tubes may be viewed here.