Quote:
Originally Posted by OneCosmos
Oh, and not stray too far from my own thread exactly why are longer refractors e.g.f15 considered planetary killers?
Yes you'll get more magnification with the same eyepiece than on a shorter scope but the atmosphere prevents going too high anyway and you can always use a shorter eyepiece with the faster refractor to achieve the same. Is there something else about the views through a long slow refractor?
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For professional achromats 100-150 years ago it is traditional for them to be f15 or thereabouts. I think there is a benefit in the long focal ratios in terms of depth of focus. For a more detailed analysis please have a look at this link to Neil English's article.
http://www.cloudynights.com/page/art...-fiction-r2452