Reduces exposure time and gives a larger, flatter field with various refractors.The camera-facing rear thread on the Planostar unit is T2 (M42) male, which allows the use of the Starwave DSLR Adapter for Canon/Nikon, and various T2 spacers for use with Altair and other CMOS cameras.
Spacing from rear flat shoulder of the PlanoStar to the camera sensor plane varies, and one can use the Altair Astro T2 variable spacer system to fine-tune the optimum distance for their particular chip and filter setup.