Eliminate the need to make focus adjustments when changing telescope eyepieces
With parfocal ring equipped telescope eyepieces you can change magnifications quickly and easily
This set of 3 Alstar Parfocal Rings lets you make a set of non-parfocal 1.25" telescope eyepieces parfocal for more efficient observing
High grade Schott optical glass is vat dyed for even color coating; then anti reflection coated for maximum light throughput; each filter has a metal filter cell and is threaded for use with 1.25 inch telescope eyepieces and filter threaded accessories
The filter mount is precision manufactured from metal and is extremely thin to minimise shadowing and diffraction; the threads on both sides of the filter make it also possible to combine different filters