A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Astronomy and Astrophysics » Amateur Astronomy
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

AFOV vs Aperture Poll



 
 
Thread Tools Display Modes
  #1  
Old December 29th 03, 02:22 AM
Tony Flanders
external usenet poster
 
Posts: n/a
Default AFOV vs Aperture Poll

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
  #2  
Old December 29th 03, 02:30 AM
Brian Tung
external usenet poster
 
Posts: n/a
Default AFOV vs Aperture Poll

Tony Flanders wrote:
* 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.

BTW, I don't hem and haw--not on this issue, since I've given it some
thought in the past in response to similar questions.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt
  #3  
Old December 29th 03, 02:30 AM
Brian Tung
external usenet poster
 
Posts: n/a
Default AFOV vs Aperture Poll

Tony Flanders wrote:
* 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.

BTW, I don't hem and haw--not on this issue, since I've given it some
thought in the past in response to similar questions.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt
  #4  
Old December 29th 03, 04:08 AM
Michael A. Covington
external usenet poster
 
Posts: n/a
Default AFOV vs Aperture Poll

In my youth (the early 1970s), 50 degrees *was* wide field. For a while
there, my best eyepiece was a Ramsden with a 30-degree field.

I would choose an 8-inch with 20-mm-eye-relief eyepieces over a 10-inch with
conventional eyepieces.

And my preferred AFOV is about 60 to 65 degrees. Radians and Pentax XLs for
me!


  #5  
Old December 29th 03, 04:08 AM
Michael A. Covington
external usenet poster
 
Posts: n/a
Default AFOV vs Aperture Poll

In my youth (the early 1970s), 50 degrees *was* wide field. For a while
there, my best eyepiece was a Ramsden with a 30-degree field.

I would choose an 8-inch with 20-mm-eye-relief eyepieces over a 10-inch with
conventional eyepieces.

And my preferred AFOV is about 60 to 65 degrees. Radians and Pentax XLs for
me!


  #6  
Old December 29th 03, 04:09 AM
Bill Ferris
external usenet poster
 
Posts: n/a
Default AFOV vs Aperture Poll

Tony Flanders wrote:
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.


Where lunar/planetary observing is concerned, the 12-inch under would obviously
outperform a pair of 10x50 binocs, regardless of light pollution. But for
deep-sky observing, dark and transparent skies are the key.

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.

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

  #7  
Old December 29th 03, 04:09 AM
Bill Ferris
external usenet poster
 
Posts: n/a
Default AFOV vs Aperture Poll

Tony Flanders wrote:
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.


Where lunar/planetary observing is concerned, the 12-inch under would obviously
outperform a pair of 10x50 binocs, regardless of light pollution. But for
deep-sky observing, dark and transparent skies are the key.

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.

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

  #8  
Old December 29th 03, 05:14 AM
Michael A. Covington
external usenet poster
 
Posts: n/a
Default AFOV vs Aperture Poll

"Bill Ferris" wrote in message
...

Where lunar/planetary observing is concerned, the 12-inch under would

obviously
outperform a pair of 10x50 binocs, regardless of light pollution. But for
deep-sky observing, dark and transparent skies are the key.

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.

Amen! A few years ago, the tour guide at Kitt Peak was a little puzzled
that instead of lining up inside the 16-inch dome, I was outside reclining
on a boulder, using my 8x40 binoculars. But then I told him what I was
observing... galaxies down to 9th mag. or more... and so forth...

I can use a telescope back home. I can't see what I was seeing in those
binoculars!

(And boulders are handy too. We need one for the yard...)



  #9  
Old December 29th 03, 05:14 AM
Michael A. Covington
external usenet poster
 
Posts: n/a
Default AFOV vs Aperture Poll

"Bill Ferris" wrote in message
...

Where lunar/planetary observing is concerned, the 12-inch under would

obviously
outperform a pair of 10x50 binocs, regardless of light pollution. But for
deep-sky observing, dark and transparent skies are the key.

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.

Amen! A few years ago, the tour guide at Kitt Peak was a little puzzled
that instead of lining up inside the 16-inch dome, I was outside reclining
on a boulder, using my 8x40 binoculars. But then I told him what I was
observing... galaxies down to 9th mag. or more... and so forth...

I can use a telescope back home. I can't see what I was seeing in those
binoculars!

(And boulders are handy too. We need one for the yard...)



  #10  
Old December 29th 03, 05:27 AM
starburst
external usenet poster
 
Posts: n/a
Default 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.



 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Binoculars field of view in degrees Jon Isaacs Amateur Astronomy 9 September 13th 03 05:25 AM
Definition of aperture. Chris L Peterson Amateur Astronomy 7 September 10th 03 06:35 PM
Aperture Does NOT Rule Jon Isaacs Amateur Astronomy 57 August 26th 03 01:13 AM
SCT CO and Aperture question Roger Hamlett Amateur Astronomy 3 August 8th 03 08:14 AM
Getting a feel for aperture increase? Ron B[ee] Amateur Astronomy 21 August 2nd 03 01:09 AM


All times are GMT +1. The time now is 02:59 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.