AFOV vs Aperture Poll

Make it five. Desert Island... no light polution... dark skies... mmmm. I'll
take the aperture any day of the week and twice on Sunday. I remember when
my kellner with a 40 degree field was a big step up. I can live with 50
degree fields and deeper limiting magnitude.

Chris

* Three people (Howard Lester, David Knisely, and me)
after hemming, hawing, and qualifying, come down quite
clearly on the side of aperture. From our point of
view, AFOV is definitely a second-order issue, to
be considered only after first-order issues like
aperture.

Four, actually. I'm not sure why Google is refusing to archive my posts
on this thread, since I don't put that particular header in my posts.

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.

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.

- Tony Flanders

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.

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.

- Tony Flanders

Aperture.

"Tony Flanders" wrote in message
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.

I mentioned Plossls and Naglers specifically, but my real
intention was to assume that all other things are equal
except the apertures of the scopes and the AFOV of the EPs.

Needless to say, this is not a realistic scenario.
Nonetheless, the results are quite instructive; people
fall into four camps:

* 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.

* Three people (Howard Lester, David Knisely, and me)
after hemming, hawing, and qualifying, come down quite
clearly on the side of aperture. From our point of
view, AFOV is definitely a second-order issue, to
be considered only after first-order issues like
aperture.

* Two people (Bill Meyers and Stephen Paul) come down
quite clearly on the side of AFOV, citing in particular
the esthetic benefits of a wide AFOV.

* Two people (Axel and Bill Ferris) lean towards aperture
but qualify this depending on the details of the
circumstances, citing primarily the practical
(rather than esthetic) benefits of a wide AFOV.

I am not sure that I like my use of the term "esthetic"
above; after all, one could argue that *all* visual
observing is fundamentally driven by esthetics. Visual
observing is not completely dead as a means of obtaining
practical data, but it is at a pretty severe disadvantage
compared to electronic imaging.

It is also interesting that despite the relatively low value
that I place on the esthetics of AFOV, I place a very high
value on the esthetics of dark skies, as evidenced by my
other thought experiment, where I choose lifelong exile
under dark skies with 10x50 binoculars to a life under
perpetual full Moon with a 12-inch scope. This is clearly
a matter of esthetic preference, because by any reasonable
measure, one can see *far* more with a 12-inch scope under
full Moon than with 10x50 binoculars under a dark sky.

- Tony Flanders

Aperture.

"Tony Flanders" wrote in message
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.

I mentioned Plossls and Naglers specifically, but my real
intention was to assume that all other things are equal
except the apertures of the scopes and the AFOV of the EPs.

Needless to say, this is not a realistic scenario.
Nonetheless, the results are quite instructive; people
fall into four camps:

* 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.

* Three people (Howard Lester, David Knisely, and me)
after hemming, hawing, and qualifying, come down quite
clearly on the side of aperture. From our point of
view, AFOV is definitely a second-order issue, to
be considered only after first-order issues like
aperture.

* Two people (Bill Meyers and Stephen Paul) come down
quite clearly on the side of AFOV, citing in particular
the esthetic benefits of a wide AFOV.

* Two people (Axel and Bill Ferris) lean towards aperture
but qualify this depending on the details of the
circumstances, citing primarily the practical
(rather than esthetic) benefits of a wide AFOV.

I am not sure that I like my use of the term "esthetic"
above; after all, one could argue that *all* visual
observing is fundamentally driven by esthetics. Visual
observing is not completely dead as a means of obtaining
practical data, but it is at a pretty severe disadvantage
compared to electronic imaging.

It is also interesting that despite the relatively low value
that I place on the esthetics of AFOV, I place a very high
value on the esthetics of dark skies, as evidenced by my
other thought experiment, where I choose lifelong exile
under dark skies with 10x50 binoculars to a life under
perpetual full Moon with a 12-inch scope. This is clearly
a matter of esthetic preference, because by any reasonable
measure, one can see *far* more with a 12-inch scope under
full Moon than with 10x50 binoculars under a dark sky.

- Tony Flanders

* 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

* 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

Make it six... a wide field view of something isn't worth much if you can't
see the "something" in the first place.

"starburst" wrote in message
...
Make it five. Desert Island... no light polution... dark skies... mmmm.
I'll
take the aperture any day of the week and twice on Sunday. I remember when
my kellner with a 40 degree field was a big step up. I can live with 50
degree fields and deeper limiting magnitude.

Chris

* Three people (Howard Lester, David Knisely, and me)
after hemming, hawing, and qualifying, come down quite
clearly on the side of aperture. From our point of
view, AFOV is definitely a second-order issue, to
be considered only after first-order issues like
aperture.

Four, actually. I'm not sure why Google is refusing to archive my posts
on this thread, since I don't put that particular header in my posts.

Make it six... a wide field view of something isn't worth much if you can't
see the "something" in the first place.

"starburst" wrote in message
...
Make it five. Desert Island... no light polution... dark skies... mmmm.
I'll
take the aperture any day of the week and twice on Sunday. I remember when
my kellner with a 40 degree field was a big step up. I can live with 50
degree fields and deeper limiting magnitude.

Chris

* Three people (Howard Lester, David Knisely, and me)
after hemming, hawing, and qualifying, come down quite
clearly on the side of aperture. From our point of
view, AFOV is definitely a second-order issue, to
be considered only after first-order issues like
aperture.

Four, actually. I'm not sure why Google is refusing to archive my posts
on this thread, since I don't put that particular header in my posts.

(Tony Flanders) wrote in message m...

But for star clusters, and particularly globular clusters, the 12-inch
scope under heavy light pollution would have a *huge* advantage.

Oh yes, then there's planetary nebulae too. I can think of two planetary
nebulae that are interesting in 10x50 binoculars, namely the Helix and M27.
Maybe M97. The rest are visible as stars or slightly fuzzy stars, if at all.

In a 12-inch scope, however, there are dozens of planetary nebulae bright
enough to show lots of structure even under very heavy light pollution.

- Tony Flanders