Quote:
Originally Posted by terrynz
It's not a glass plate, its a set of lenses designed to project a flat field. Also the corector plate is a different design, hence for hyperstar to work a spacing ring is required to move further away from the primary mirror. In short they are different to the ACF.
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In the new celestron HD range I believe the primary and secondary are still spherical so there is an ideal spacing which is the same as a stock SCT. The corrector lenses inside the baffle tube give a flat field. I'm pretty sure the hyperstar is the same unless it has changed again. I was told it was at the time by starizona. The Meade ACF secondary is not spherical to correct for abberations.