Thread types
In astrophotography, various components from different manufacturers are often combined with each other. Thereby, short forms for designations of the threads appear again and again, which can be confusing for a beginner. The following table gives an overview of the most important thread types.
| Thread type | Specification | Remark | Figure |
| T2 | M42x0.75 |  Source: Lumpenpack at German Wikipedia, GPL, via Wikimedia Commons | |
| SC-Thread | 2"x1/24" (50.8x1.058) | (To Schmidt-Cassegrain) 2" thread with 24 threads per inch |  |
| C-Mount | 1"x1/32" (25.4x0.794) | flange focal distance of 17.526 mm |  Source: Alexander.stohr, Public domain, via Wikimedia Commons (translated) |
| CS-Mount | 1"x1/32" (25.4x0.794) | flange focal distance of 12.5 mm | |
| M28,5 filter thread for 1,25" filter | M28.5x0.5 resp. M28.5x0.6 | Filter has outer dimension of 1.25" (31.75 mm) and a stepped thread M28 Unfortunately, the manufacturers use partly different pitches. |  Source: https://www.teleskop-express.de (added dimensions) |
| M48" filter thread for 2" filter | M48x0.6 resp. M48x0.75 | Filter has outer dimension of 2" (50.8 mm) and a stepped thread M48. Unfortunately, the manufacturers use partly different pitches. The most common is M48x0.75. |  Source: https://www.teleskop-express.de (added dimensions) |
| 1/4" UNC-Tripod thread | 0.25"x1/20" (6.35x1.27) | 0.25" thread with 20 threads per inch (35 mm format cameras) |  Source: https://www.teleskop-express.de |
| 3/8" UNC-Tripod thread | 0.375"x1/16" (9.53x1.5875) | 0.375" thread with 16 threads per inch (Medium and large format cameras) |  Source: https://www.teleskop-express.de |
