This is an amazing piece of glass, which transforms both the visual and imaging experience when using either the TOA-130 or 150.The field curvature of the TOA needs be corrected for a satisfying imaging or viewing experience, and other flatteners just do not work nearly as well.
The 67-FL is very forgiving of backfocus distances when used with smaller imaging sensors (up to about 24 millimeters diagonal, and with larger sensors is absolutely required. It is a must-have for imaging of any sort at the native focal length, and is really a should-have for visual use as well, flattening the visual field very effectively. Even though it adds nearly $1000 to the cost of an already-expensive refractor, the TOA cannot live up to its potential without a matched flattening element in the optical train.
Check out the following link:
http://www.takahashi-europe.com/en/T...tics.spots.htm
$750 posted anywhere in australia
