Set of three 1 mm thick spacer rings that can be used in special circumstances to modify the back focus spacing of your field flatteners or telecompressor connectors.
Here are some recommendations from Astro-Physics to achieve proper spacing.
- Increase the spacing by adding one, two, or three spacer rings to 2.7" extensions (EXT27-...) in your imaging train
- If you own a field flattener or TCC telecompressor corrector with male 3.27" threads, first you can reduce the distance by switching to a shorter 3.27" back focus spacer extension (EXT327-...). Then, you will either add the appropriate number of these 2.7" rings to achieve the optimum spacing, use the 3.27" spacer rings (SRSET-327), or a combination of both. You can easily experiment with 1 mm increments
- These spacer rings are designed to easily slip over the 2.7" thread of the telecompressor correctors and CCD field flatteners
Below are some helpful links for usage with these spacer rings:
Field Flatteners, TCCs, and QUADTCC Imaging Train Options
Determining Ring Spacing Options