Re: na120s from vixen

I'm not sure but I think the NA120 is a Petzval with the extra element aimed at flattening the field. I believe (maybe Roland or one of the gurus will chime in) that a Petzval design can be made to show less CA than a regular achromat, but does't automatically. So the main goal of the scope may have been to get a flatter field for wide view imaging, where the ca will make much less difference, rather than to reduce the ca below that of a normal achromat.

NA 120 is not a Petzval design. In reality it is basically an Achromat. It is not a semi apo nor is it an Apo. If your expecting that kind of performance I think your going to be dissappointed.

Clear Skies
Dwight L Bogan

I had a NA-120 three years ago, it was a darn good scope! Great for sky sweeping and good for higher power work.

It's not a AP or Tak when it come to color correction!

Chas