In terms of attachment to the mechanism, a tube-mounted prismatic rail provides a very convenient and practical option. The prismatic rail is most often attached to two tube rings rather than directly to the tube, allowing the tube to rotate in the rings.
The screws on the aluminium surface can become indented with repeated use, and for those who are concerned about this aesthetic issue, the Bresser 20 cm prism rail with wear-resistant steel sideplate is a demanding solution.
The length of the prism rail is for the full length, with a maximum width of approximately 42 mm uniformly, allowing it to be fitted to all mechanisms that require Vixen standard telescope mounts. Without being exhaustive, these are:
- SkyWatcher EQ-3, EQ-5, HEQ-5, EQ-6 and their Pro versions
- Celestron CG-4, Advanced EQ-5 goto, CGEM
- Meade LXD 75, LX80
- AZ-4, AZ-GT Star Discovery, Virtuoso, AZ3-R, AZ-5, AZGTi (14 cm prismatic rails cannot be used with them!)