Re: [Utah-astronomy] Eyepieces (was Jupiter Impact Scar)
Well, last time I checked M57 was a deep-sky object, so you actually are agreeing with me, lol. But I should clarify a few things for the nit-pickers. By "planetary" eyepiece, I mean a short-focal-length eyepiece capable of yielding essentially perfect imagery of low-contrast planetary markings, and fine detail near the diffraction limit under ideal viewing conditions. Most observers will consider eyepieces of single-digit focal length elegible to compete in this category, and like Don, I would give some ground to allow eyepieces with focal lengths in the low teens to be included as well, since the modern amateur astronomer now has primary focal lengths available that will yield usefull high powers with such eyepieces- most didn't 30 or 40 years ago. Barlow lenses must be excluded. So, no one is saying that 31mm and 35mm eyepieces, especially Tele Vues, are not terrific eyepieces, it's just that they should not be included with the shorter-focal-length eyepieces normally associated with viewing Mars or Jupiter at very high magnifications. It's been said about airplanes that a design that does "everything", does nothing *well*. Optics are subject to the same constraints, from my experience. You want ultra-wide fields, you have to give a little ground in clarity and throughput. You want perfect resolution, you have to give up some of that wide field. On Sat, Aug 1, 2009 at 4:23 PM, Rob Ratkowski Photography < ratkwski@hawaii.rr.com> wrote:
Well Chuck
I have to disagree some I just posted a photo where I'm using a 31mm Panoptic to look at M57 ( a 'planet'ary) and the view was quite nice and it appeared to be about dime sized http://www.slas.us/gallery2/main.php?g2_itemId=2163
Just for grins,Aloha Rob
Rob, what do you get 500x with the 31 mm? not really an amateur telescope you were using.
Well, last time I checked M57 was a deep-sky object, so you actually are
agreeing with me, lol.
But I should clarify a few things for the nit-pickers. By "planetary" eyepiece, I mean a short-focal-length eyepiece capable of yielding essentially perfect imagery of low-contrast planetary markings, and fine detail near the diffraction limit under ideal viewing conditions. Most observers will consider eyepieces of single-digit focal length elegible to compete in this category, and like Don, I would give some ground to allow eyepieces with focal lengths in the low teens to be included as well, since the modern amateur astronomer now has primary focal lengths available that will yield usefull high powers with such eyepieces- most didn't 30 or 40 years ago. Barlow lenses must be excluded.
So, no one is saying that 31mm and 35mm eyepieces, especially Tele Vues, are not terrific eyepieces, it's just that they should not be included with the shorter-focal-length eyepieces normally associated with viewing Mars or Jupiter at very high magnifications.
It's been said about airplanes that a design that does "everything", does nothing *well*. Optics are subject to the same constraints, from my experience. You want ultra-wide fields, you have to give a little ground in clarity and throughput. You want perfect resolution, you have to give up some of that wide field. On Sat, Aug 1, 2009 at 4:23 PM, Rob Ratkowski Photography < ratkwski@hawaii.rr.com> wrote:
Well Chuck
I have to disagree some I just posted a photo where I'm using a 31mm Panoptic to look at M57 ( a 'planet'ary) and the view was quite nice and it appeared to be about dime sized http://www.slas.us/gallery2/main.php?g2_itemId=2163
Just for grins,Aloha Rob
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They were doing some work on the Faulkes scope and needed an eyepiece for part of the initial adjustments, so Mark came over and asked if I'd like to look thru the scope. He then explained that he had mounted an eyepiece (no diagonal) and the view was pretty good. M57 could be seen with color and the central star, it looked dime sized in the FOV but I must admit that it was a quick view in an unusual position. A diagonal and a chair would have helped ;^) Either way, it was a memorable look with a photo. I guess the magnification was up around 3300X , I believe the EP was a 31mm Pan, maybe a 41Pan Mark Elphick of Faulkes is a very fine fellow, always helping when we have guests up, always glad to show the scope and talk about equipment and projects that FTN conducts. Aloha Rob
participants (3)
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Chuck Hards -
erikhansen＠TheBlueZone.net -
Rob Ratkowski Photography