Quote:
Originally Posted by bobson
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Bob,
I had a lot more than a little bit to do with that review. I actually guided Mike in all the field testing for it
The Naglers are not scaled designs hence they are not comparable across focal lengths. Similarly the Pentax XW's are not scaled designs and are not comparable across focal lengths. The 13mm Nagler and 14mm Pentax XW have
ZERO comparison attributes with the 10mm Pentax XW and the barlowed 17mm Nagler T4.
What you need to understand is that a 2X barlow more often than not gives an amplification factor greater than 2X which is dependent on the barlow itself and the eyepiece design. Usually the amplification of a 2X barlow is about 2.2X . This means your 17mm Nagler T4 barlowed is working like a 7.7mm eyepiece. Essentially you are comparing a 10mm eyepiece with a 7.7mm eyepiece which you simply cannot do, particularly at the short end of the scale. All you are really saying is you prefer the higher power view. I have absolutely no doubt any
"PERCEIVED" advantages you see with the barlowed 17mm Nagler T4 over the 10mm Pentax XW (as a lunar/planetary eyepiece combination) arise because of the
"SIGNIFICANT" magnification difference between the two.
Also Bob when reading internet reviews and comments you need to learn how to sort
"the wheat from the chaff".
Cheers,
John B