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Message: <blockquote data-quote="ailevin" data-source="post: 3655027" data-attributes="member: 140149">Joachim,I agree that all things being equal, and at a given magnification wider apparent field is better. However, I think more in terms of actual field of view, both for astronomical and terrestrial use.  For instance, consider looking at the Double Cluster in Perseus.  In a large telescope, say a 28" reflector, even a low power eyepiece with very wide apparent field is not going to frame the object as pleasingly as the same eyepiece in a smaller instrument (assume similar F ratio). The minimum magnification of the large instrument will be quite high giving a very small actual field.  I once experienced an extreme case of this.  We were looking at M13, the globular cluster in Hercules using the Mount Wilson 60" telescope.  I thought we were pointed to the wrong object, because all I saw was an extended open cluster.  Then I looked through the "finder scope," an 8 inch Schmidt Cassegrain, and sure enough there was the familiar object.  It was just that with the extreme magnification of the 60" we had resolved the core of M13 and couldn't see its shape/boundaries.  My soda straw analogy was again largely referring to actual field of view.  For instance, if you are looking through a telescope and have a 1 degree actual field of view, there are something like 20,000 unique places to point the telescope in a hemisphere. Thus finding something in the sky and pointing the telescope at it is like searching for something "through a soda straw."  That is why we tend to use finders or low power eyepieces on smaller telescopes to get onto the object we want to view.One last example.  My 7x50 binocular have just over 50 degree apparent field of view, and my 15x45 binoculars have about 67 degree apparent field of view, yet it is considerably easier to find things in the 7x50 than in the 15x45, because the 7x50 has a 7.5 degree actual field of view and the 15x45 has a 4.5 degree field of view.  The 7x50 actually sees 2.8=(7.5/4.5)^2 as much sky as the 14x45.Again, I agree with you that wider apparent field is pleasing, and also different observers have different preferences for what sort of magnification and eyepiece designs they prefer.Alan</blockquote>

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