Celestron's M42 Spacer Ring kit includes three different length spacer rings to achieve the proper back-focus distance with our popular Celestron optical tubes and T-thread camera adapters.
How to Use
Depending your method of astrophotography (DSLR or CCD/CMOS), there are two ways to use the M42 Spacer Ring. If you are using a DSLR, place the desired M42 Spacer Ring between your T-Ring and your T-Adapter for your optical tube. If you are using a CCD or CMOS camera, place the desired M42 Spacer Ring between the camera and the T-Adapter for your optical tube.
Below is a quick guide to help you determine which spacer ring to use for our EdgeHD, Schmidt-Cassegrain, and RASA 8 optical tubes:
| Spacer Ring Size: | Works best with: |
| 7.5mm | Provides proper spacing with RASA 8 for many ZWO cameras |
| 12mm | Provides proper spacing with RASA 8 for many Atik cameras |
| 30mm | Converts ZWO camera w/filter slider to 55mm back-focus standard for use with Schmidt-Cassegrain & EdgeHD |
Specifications
| General | |
|---|---|
| Barrel Size Diameter: | 1.25" (31.75mm) |
| Focal Length: | 10mm (.39") |
| Field Stop Diameter: | 14.7mm (.58") |
| Apparent Field of View: | 60° |
| Optical Design: | Proprietary |
| Number of Lens Elements: | 5 |
| Number of Lens Groups: | 4 |
| Optical Coatings: | Fully Multi-Coated |
| Eye Relief: | 16mm (.63") |
| Parfocal: | Yes |
| Filter Threads: | 1.25" (M28.5X0.6) |
| Eye Guard: | Yes- roll up |
| Body Material: | Aluminum |
| Weight: | 2.82 oz (80 g) |
| Dimensions: | 58mm x 36.5mm x 36.5mm (2.28" x 1.44" x 1.44") |
