|
I have now come to the conclusion that this article has not been properly researched and checked before posting to the internet, it contains a lot of errors.
"Orthoscopics
Four-element "orthos" were once prized as the best all-around eyepiece, but they've lost ground among the amateur ranks because of a narrower field compared to other modern designs like Plossls. Orthos yield excellent sharpness, color fidelity, and contrast. They have longer eye relief than Kellners, though not as long as most Plossls. They are especially suited to planetary, lunar, and double star observing."
An orthoscopic in fact has slightly longer eye-relief than a plossl, not the other way around as stated in the article. The eye-relief of an orthoscopic is generally 75% to 80% of its focal length and a plossl is 70% to 75% of its focal length.
I am not even going to bother reading any further, clealry the person who wrote the article is no expert and is regurgitating tid bits he has picked up. Go buy a copy of Starware, the current edition is #3
CS-John B
|