A lot of astrophotographers are unaware that the Series III
'Stiletto' is a true knife-edge focuser. While our regular
ronchi gratings are far easier to use, the True Knife-Edge Accessory
we offer converts the Series III 'Stiletto' to a premier knife-edge
focuser in seconds. Our True Knife-edge is interchangeable with the
ronchi screens we use, and requires no recalibration of the unit at all. The changeover from one to the other takes about a minute. If you've got the patience to learn how to use a knife edge, we have the product!
Compared to other knife-edge approaches, the Series III offers
tremendous advantages in convenience and seeing. The Series III
magnifies the light pattern for easier detection of the focal point,
and the swivel diagonal allows you to put yourself in a
comfortable viewing position. If you have tried other knife edge
techniques, then you already know that they are no fun at all
and are difficult to master. The Series III 'Stiletto' True Knife
Accessory does save the day (er, night).
To learn more about true knife-edge focusing, visit our website and
take a look at our special tutorial on how it all works at