Quote:
Originally Posted by gregbradley
Hi,
Firstly the term "APO" gets bandied around by scope manufacturers and has become degraded as a term.
It actually means all colours come to focus at the same or extremely closely the same point.
A Chinese ED doublet will not be able to comply with that definition. It will be sharp and a pleasant view but it will have some colour on bright objects to one degree or another.
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there are currently a few images in the deep sky version with the Chineese 127 ...... of note is the blue halos around the brighter stars, in this case the APO term really should not be used, and as greg says somewhat diminishes the term. Having said that, at 127mm that you can buy for 1200 or so dollars, the william optics 132 is 5000 and the Televue 127 is 10000 so its probably ok value for what you pay.