Extension tubes like this are often useful for achieving focus.
The set contains three extension sleeves of different lengths: 7.5mm, 12mm and 30mm
Example of use:
- 7.5mm provides the correct distance for many ZWO cameras with RASA 8
- 12mm offers the correct distance for many Atik cameras with RASA 8
- 30mm converts ZWO cameras with filter slides to have a standard back focus of 55mm for use with a Schmidt-Cassegrain & EdgeHD
Sample calculation:
RASA 8 with a ZWO ASI 183 MC PRO camera:
- Back focus distance required for RASA 8 with included M42 (T-2) camera adapter: 25mm
- ZWO ASI 183 MC PRO back focus: 17.5mm
- In order to achieve the correct working distance, a 7.5mm spacer ring is required
Example: RASA 8 with an ATIK Horizon camera:
- Back focus distance required for RASA 8 with included M42 (T-2) camera adapter: 25 mm
- Back focus for ATIK horizon: 13mm
- In order to achieve the correct working distance, a 12mm M42 spacer ring is required
