Product Reviews
- Reviews
- Questions

Very useful diagnostic tool.
Find a bright star. Center in eyepiece. Drop in this Ronchi EP. Rack inside and outside focus til you see five lines (inside and then outside) compare to Ronchi chart. That's it. No arguing with ronchi's supreme authority. Tells you what to fix and if you've fixed it with repeated analysis. Nothing better in the field.

10" mirror testing
This item performed perfectly. It is easy to use and interpret mirror problems with the included images of typical mirror problems, Thank you.

Easy to use
After trying my hand at star testing, I couldn't converge to a diagnosis. This is quick and easy. Point at Polaris and focus in and out. The charts with the item and online give a quick diagnosis.
defective, but works fine after I repaired it.
The ronchi grating in mine fell out. Not properly glued in. I used optical glue to glue my grating back into the eyepiece. That's because I'm in Canada and returning purchases to the USA after importing them is expensive and a pain because of Canada Customs rules. However, now the ronchi eyepiece works fine. I still like OPT, in case you're wondering.
Ronchi Eyepiece
only buy this if your prepared to find out your mirror is a dog, it works quite well in good seeing..m
Herd Newman Ronchi eyepiece
Excellent. I used it in combination with my artificial star to determine the rotational orientation between the primary and corrector plate of a SCT