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AFOV vs Aperture Poll
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#22
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AFOV vs Aperture Poll
Jon Isaacs wrote:
snip I have gotten used to the wider fields of view so viewing through a Plossl seems like looking down a drain pipe. unsnip I'm with you there, Jon. Last night, before going to work, I observed Mars and Luna through my Synta 66 degree bargains (6mm & 9mm) and through my 12.5mm & 7.5mm Sirius plossls (50 degree). The side by side comparison was astonishing. . .yet I remember how impressed I was with the plossls FOV that were an upgrade from my Meade MA kellners. -- Martin Remove "ilikestars" from email address to reply |
#23
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AFOV vs Aperture Poll
Jon Isaacs wrote:
snip I have gotten used to the wider fields of view so viewing through a Plossl seems like looking down a drain pipe. unsnip I'm with you there, Jon. Last night, before going to work, I observed Mars and Luna through my Synta 66 degree bargains (6mm & 9mm) and through my 12.5mm & 7.5mm Sirius plossls (50 degree). The side by side comparison was astonishing. . .yet I remember how impressed I was with the plossls FOV that were an upgrade from my Meade MA kellners. -- Martin Remove "ilikestars" from email address to reply |
#24
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AFOV vs Aperture Poll
Tony Flanders wrote:
Here are the results of a "poll" that I initiated in the middle of a thread with the dopey title "What's so Great about Tele Vue Eyepieces?" I was hoping to get some sense of the value that people place on a wide AFOV by presenting the following choice: Suppose you had to spend the rest of your life on a desert island with one of the following sets of equipment, which would you choose? * An 8-inch scope with a full set of 80-degree-AFOV EPs. * A 10-inch scope with a full set of 50-degree-AFOV EPs. Since I have 80 AFOV eyepiece my 80 years old father have less of difficulties of looking at my scope. Therfore, my choice would be 8inches with 80 AFOV eyepieces to allow me to observe until the end of my days ;-) |
#25
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AFOV vs Aperture Poll
Tony Flanders wrote:
Here are the results of a "poll" that I initiated in the middle of a thread with the dopey title "What's so Great about Tele Vue Eyepieces?" I was hoping to get some sense of the value that people place on a wide AFOV by presenting the following choice: Suppose you had to spend the rest of your life on a desert island with one of the following sets of equipment, which would you choose? * An 8-inch scope with a full set of 80-degree-AFOV EPs. * A 10-inch scope with a full set of 50-degree-AFOV EPs. Since I have 80 AFOV eyepiece my 80 years old father have less of difficulties of looking at my scope. Therfore, my choice would be 8inches with 80 AFOV eyepieces to allow me to observe until the end of my days ;-) |
#26
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AFOV vs Aperture Poll
Tony Flanders wrote:
[I wrote:] Given the choice between the binocs under pristine skies and a 12-inch under heavily light-polluted skies, I'd take the binocs under dark skies without hesitation. And it wouldn't be a choice based on aesthetics. It would be based on the superior performance of the smaller aperture under truly dark skies. Think so? I would agree with you if the dark-sky instrument were, say, a 100mm scope. But the best dark-sky subjects are galaxies, and 10x50 binoculars are simply too small to show any detail in most galaxies. Sure, I can *detect* mag 9 galaxies in my 10x50 binoculars under dark skies, but that's about the end of it -- they show as featureless blobs with averted vision. Which is exactly how those same galaxies would show in the 12-inch scope under heavy light pollution. But for star clusters, and particularly globular clusters, the 12-inch scope under heavy light pollution would have a *huge* advantage. Not only do the binoculars not have enough aperture to show globular clusters well, they also don't have enough magnification. When stating my preference for 10x50 binoculars under dark skies, it was those globular clusters that were hardest to give up. M5 is stupendous through a 12-inch scope even under very heavy light pollution. So where do the binoculars have a clear advantage? Perhaps 4 or 5 very large nebulae, like the North America. Perhaps half a dozen galaxies, which are big and bright enough to show real detail even in 10x50 binoculars. But for me, the crowning advantage of the binoculars would be for viewing the biggest and best galaxy of all, namely our own Milky Way. Comparing the views in 10x50 binoculars used under pristine (22.0 MPSA) skies against those in a 12-inch aperture under heavily light-polluted (18.0 MPSA) skies, the binoculars are going to have a distinct advantage on nebulous objects and objects large enough to require a wide field, low power view. The telescope's advantage would be limited to small, high surface brightness objects. Let's begin with the Messier catalog. Among the 110 objects are nine diffuse nebulae and open clusters associated with nebulae: M1, M8, M16, M17, M20, M24, M42, M43 and M78. All will appear larger and more contrasty in the 10x50 binoculars under true dark skies than in a 12-inch aperture under heavy light pollution. In fact, the nebulosity associated with M20 will probably not be visible in 12-inch aperture. And M24--at 2-degrees in size--will not be fully framed by the larger scope. There are 41 galaxies, including NGC 5195 and NGC 5866, in the Messier catalog. M31, M33 and M101 all would clearly be superior in the binoculars. And the low surface brightness Seyfert galaxy, M74, which would be visible in the binoculars, may not be visible in the 12-inch. Among the other spirals, you simply won't see any structure in these under really bright skies. All are visible in the binoculars. If the telescope holds an advantage it would be an ability to detect a stellar core region. Messier's catalog includes four planetary nebulae: M27, M57, M76 and M97. Again, the binoculars will have an edge in contrast. These are fairly well defined objects. The binoculars may have an edge on M27, which has some delicate outlying nebulosity. The 12-inch would have a clear edge with M57, which is a classic example of a small, bright and well-defined object. The Messier globulars (29) are another example of large, high surface brightness object where the telescope would still hold an edge. Excluding those open star clusters associated with nebulosity, the Messier catalog includes 28 such objects. Four (M7, M41, M44 and M45) are 54' or larger in diameter. They would require at least a 1.5-degree true field to fully encompass with a reasonable amount of sky as framework. The sky brightness in the 12-inch at such a low magnification would be overwhelming. You'll see more stars in these four in the binoculars. An impressive number of objects in the Messier catalog would appear larger and more detailed, and would show more nebulosity or more stars in the binoculars than in the much larger telescope. This is particularly impressive when you consider that the Messier catalog and NGC are mostly populated by objects discovered with narrow field telescopes. If we expand our horizons, the advantage of using binoculars under a pristine sky becomes obvious. Large nebulae, such as the North America and the Veil, will be clearly superior in the binoculars. The same is true for large stellar associations, such as the Alpha Persei stellar association and the Coathanger. The summer and winter Milky Way are filled with many such objects--not all of which have been catalogued or been given cute common names--but all of which will be much more detailed and interesting in the binoculars. Comets, variable stars, meteor showers, lunar eclipses and aurorae; all will be better viewed with the naked eye or with binoculars under a pristine sky than with the naked eye or a 12-inch telescope under heavy light pollution. The Messier catalog just scrapes the tip of the iceberg when it comes to outstanding binocular objects for a true dark sky. But for large aperture under very bright skies, you quickly start to run out of objects as soon as you leave the Messier catalog. There's no question but that a good pair of 10x50s under pristine skies will show far more objects than a 12-inch imprisoned by heavy light pollution. Regards, Bill Ferris "Cosmic Voyage: The Online Resource for Amateur Astronomers" URL: http://www.cosmic-voyage.net ============= Email: Remove "ic" from .comic above to respond |
#27
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AFOV vs Aperture Poll
Tony Flanders wrote:
[I wrote:] Given the choice between the binocs under pristine skies and a 12-inch under heavily light-polluted skies, I'd take the binocs under dark skies without hesitation. And it wouldn't be a choice based on aesthetics. It would be based on the superior performance of the smaller aperture under truly dark skies. Think so? I would agree with you if the dark-sky instrument were, say, a 100mm scope. But the best dark-sky subjects are galaxies, and 10x50 binoculars are simply too small to show any detail in most galaxies. Sure, I can *detect* mag 9 galaxies in my 10x50 binoculars under dark skies, but that's about the end of it -- they show as featureless blobs with averted vision. Which is exactly how those same galaxies would show in the 12-inch scope under heavy light pollution. But for star clusters, and particularly globular clusters, the 12-inch scope under heavy light pollution would have a *huge* advantage. Not only do the binoculars not have enough aperture to show globular clusters well, they also don't have enough magnification. When stating my preference for 10x50 binoculars under dark skies, it was those globular clusters that were hardest to give up. M5 is stupendous through a 12-inch scope even under very heavy light pollution. So where do the binoculars have a clear advantage? Perhaps 4 or 5 very large nebulae, like the North America. Perhaps half a dozen galaxies, which are big and bright enough to show real detail even in 10x50 binoculars. But for me, the crowning advantage of the binoculars would be for viewing the biggest and best galaxy of all, namely our own Milky Way. Comparing the views in 10x50 binoculars used under pristine (22.0 MPSA) skies against those in a 12-inch aperture under heavily light-polluted (18.0 MPSA) skies, the binoculars are going to have a distinct advantage on nebulous objects and objects large enough to require a wide field, low power view. The telescope's advantage would be limited to small, high surface brightness objects. Let's begin with the Messier catalog. Among the 110 objects are nine diffuse nebulae and open clusters associated with nebulae: M1, M8, M16, M17, M20, M24, M42, M43 and M78. All will appear larger and more contrasty in the 10x50 binoculars under true dark skies than in a 12-inch aperture under heavy light pollution. In fact, the nebulosity associated with M20 will probably not be visible in 12-inch aperture. And M24--at 2-degrees in size--will not be fully framed by the larger scope. There are 41 galaxies, including NGC 5195 and NGC 5866, in the Messier catalog. M31, M33 and M101 all would clearly be superior in the binoculars. And the low surface brightness Seyfert galaxy, M74, which would be visible in the binoculars, may not be visible in the 12-inch. Among the other spirals, you simply won't see any structure in these under really bright skies. All are visible in the binoculars. If the telescope holds an advantage it would be an ability to detect a stellar core region. Messier's catalog includes four planetary nebulae: M27, M57, M76 and M97. Again, the binoculars will have an edge in contrast. These are fairly well defined objects. The binoculars may have an edge on M27, which has some delicate outlying nebulosity. The 12-inch would have a clear edge with M57, which is a classic example of a small, bright and well-defined object. The Messier globulars (29) are another example of large, high surface brightness object where the telescope would still hold an edge. Excluding those open star clusters associated with nebulosity, the Messier catalog includes 28 such objects. Four (M7, M41, M44 and M45) are 54' or larger in diameter. They would require at least a 1.5-degree true field to fully encompass with a reasonable amount of sky as framework. The sky brightness in the 12-inch at such a low magnification would be overwhelming. You'll see more stars in these four in the binoculars. An impressive number of objects in the Messier catalog would appear larger and more detailed, and would show more nebulosity or more stars in the binoculars than in the much larger telescope. This is particularly impressive when you consider that the Messier catalog and NGC are mostly populated by objects discovered with narrow field telescopes. If we expand our horizons, the advantage of using binoculars under a pristine sky becomes obvious. Large nebulae, such as the North America and the Veil, will be clearly superior in the binoculars. The same is true for large stellar associations, such as the Alpha Persei stellar association and the Coathanger. The summer and winter Milky Way are filled with many such objects--not all of which have been catalogued or been given cute common names--but all of which will be much more detailed and interesting in the binoculars. Comets, variable stars, meteor showers, lunar eclipses and aurorae; all will be better viewed with the naked eye or with binoculars under a pristine sky than with the naked eye or a 12-inch telescope under heavy light pollution. The Messier catalog just scrapes the tip of the iceberg when it comes to outstanding binocular objects for a true dark sky. But for large aperture under very bright skies, you quickly start to run out of objects as soon as you leave the Messier catalog. There's no question but that a good pair of 10x50s under pristine skies will show far more objects than a 12-inch imprisoned by heavy light pollution. Regards, Bill Ferris "Cosmic Voyage: The Online Resource for Amateur Astronomers" URL: http://www.cosmic-voyage.net ============= Email: Remove "ic" from .comic above to respond |
#28
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AFOV vs Aperture Poll
Hello, Tony,
Tony Flanders wrote: c (Bill Ferris) wrote in message ... Given the choice between the binocs under pristine skies and a 12-inch under heavily light-polluted skies, I'd take the binocs under dark skies without hesitation. And it wouldn't be a choice based on aesthetics. It would be based on the superior performance of the smaller aperture under truly dark skies. Think so? I would agree with you if the dark-sky instrument were, say, a 100mm scope. But the best dark-sky subjects are galaxies, and 10x50 binoculars are simply too small to show any detail in most galaxies. Sure, I can *detect* mag 9 galaxies in my 10x50 binoculars under dark skies, but that's about the end of it -- they show as featureless blobs with averted vision. Which is exactly how those same galaxies would show in the 12-inch scope under heavy light pollution. And which is exactly how much fainter galaxies show up in very large telescopes. You have put your finger on a much broader issue: "detect" is the right word, and the question in my mind is, why "detect" a long series of objects with averted vision, unless a particular object is intrinsically interesting( (for example, the Sagittarius dwarf, or a quasar) beyond the many many many similar objects in its class? Is it the thrill of the hunt that drives people through the Herschel II list? But for star clusters, and particularly globular clusters, the 12-inch scope under heavy light pollution would have a *huge* advantage. Not only do the binoculars not have enough aperture to show globular clusters well, they also don't have enough magnification. When stating my preference for 10x50 binoculars under dark skies, it was those globular clusters that were hardest to give up. M5 is stupendous through a 12-inch scope even under very heavy light pollution. I agree with you pretty much but "chacun a son gout" M5 is also stupendous with a 4 inch scope at 17x in my view. So where do the binoculars have a clear advantage? Perhaps 4 or 5 very large nebulae, like the North America. Perhaps half a dozen galaxies, which are big and bright enough to show real detail even in 10x50 binoculars. But for me, the crowning advantage of the binoculars would be for viewing the biggest and best galaxy of all, namely our own Milky Way. Clear skies, Bill Meyers |
#29
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AFOV vs Aperture Poll
Hello, Tony,
Tony Flanders wrote: c (Bill Ferris) wrote in message ... Given the choice between the binocs under pristine skies and a 12-inch under heavily light-polluted skies, I'd take the binocs under dark skies without hesitation. And it wouldn't be a choice based on aesthetics. It would be based on the superior performance of the smaller aperture under truly dark skies. Think so? I would agree with you if the dark-sky instrument were, say, a 100mm scope. But the best dark-sky subjects are galaxies, and 10x50 binoculars are simply too small to show any detail in most galaxies. Sure, I can *detect* mag 9 galaxies in my 10x50 binoculars under dark skies, but that's about the end of it -- they show as featureless blobs with averted vision. Which is exactly how those same galaxies would show in the 12-inch scope under heavy light pollution. And which is exactly how much fainter galaxies show up in very large telescopes. You have put your finger on a much broader issue: "detect" is the right word, and the question in my mind is, why "detect" a long series of objects with averted vision, unless a particular object is intrinsically interesting( (for example, the Sagittarius dwarf, or a quasar) beyond the many many many similar objects in its class? Is it the thrill of the hunt that drives people through the Herschel II list? But for star clusters, and particularly globular clusters, the 12-inch scope under heavy light pollution would have a *huge* advantage. Not only do the binoculars not have enough aperture to show globular clusters well, they also don't have enough magnification. When stating my preference for 10x50 binoculars under dark skies, it was those globular clusters that were hardest to give up. M5 is stupendous through a 12-inch scope even under very heavy light pollution. I agree with you pretty much but "chacun a son gout" M5 is also stupendous with a 4 inch scope at 17x in my view. So where do the binoculars have a clear advantage? Perhaps 4 or 5 very large nebulae, like the North America. Perhaps half a dozen galaxies, which are big and bright enough to show real detail even in 10x50 binoculars. But for me, the crowning advantage of the binoculars would be for viewing the biggest and best galaxy of all, namely our own Milky Way. Clear skies, Bill Meyers |
#30
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AFOV vs Aperture Poll
Hello, Jon,
My opinion as well. Clear skies, Bill Meyers, Jon Isaacs wrote: * One person (Jon Isaacs) refuses to take the bait; apples are apples, oranges are oranges, and he'll deal with the desert island when and if he has to. My solution: Pragmatic, take the 10 inch and buy those Synta 66 degree FOV eyepieces for the less than the cost of TV Plossls. Yeah, I know its cheating but its what I have done anyway, I am pretty happy with the Synta Ultrawides. I am in the position of having both 8 and 10 inch scopes, I have a pretty good idea of the difference and it is a tough call because that 50 percent extra mirror area is pretty nice but I have gotten used to the wider fields of view so viewing through a Plossl seems like looking down a drain pipe. Jon |
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