Fabrizio.
I just noticed the telescopes you are using.
At those focal ratios I am not surprised that the Clave's work well for you.
Here is a review of the Clave 10 versus Radian versus Celestron.
http://www.cloudynights.com/item.php?item_id=294
It would seem to bear out the prior assertion that not even an asymmetric lens arrangement saves the plossl from strong field astigmatism when they are used with fast focal ratio telescopes.
I'd be really interested to see a zemax plot for symmetric versus asymmetric plossl's at different primary speeds.
best
~c
Incidentally,
This is another interesting thread about the clave plossl:
http://www.cloudynights.com/ubbthrea...4/Main/3251872
I would bet my lunch that the mixed reviews are a result of using them with fast focal ratios.