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Main
Date: 28 Apr 2007 19:24:14
From: Dennis Woos
Subject: New Televue Eyepice Design
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In a talk my older son and I once gave at a club meeting, we compared the
characteristics of a 20mm 50degree afov plossl to that of a hypothetical
20mm 100degree afov "super Nagler". Well, I just got back from NEAF
(NorthEast Astronomy Forum) where Al Nagler announced and demonstrated a new
100 degree 13mm eyepiece! The field was much wider than an 82dgree Nagler,
and one could only see the field stop with considerable effort. The
question is, what do folks think is the market for such an eyepiece? Do any
Nagler owners find 82degrees limiting? Is 100degrees really useful?
I didn't get one, and not because they are not yet for sale. I did get,
courtesy of Televue, a TV 32mm plossl, a TV 20mm plossl, and a TV 2x barlow
for $75 in total, which I will give to my son as a graduation present. He
can use these with one of our scopes (6" f/8 dob) when he starts college
this fall, and get in some observing time. He intends to major in
Physics/AstroPhysics!
Dennis
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Date: 16 May 2007 05:25:02
From: Helpful person
Subject: Re: New Televue Eyepice Design
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On May 15, 10:26 pm, "George Normandin" <georg...@worldnet.att.net >
wrote:
> "Helpful person" <> wrote
>
>
>
> > Brian is correct......
>
> Then I take it you guys are disagreeing with Al Nagler and the optics text
> that he quotes (seehttp://www.televue.com/includes/Article_Ethos_Intro_tech.asp) relative to
> the two types of distortion being different and not controllable at the same
> time? You are thus claiming that the Ethos could have been designed to
> correct for both types of distortion even though Nagler says it can't be
> done?
>
> George N
The difference between the two definitions (not types) is that one is
defined as the tangent of the other.
Please visit my web site at www.richardfisher,com
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Date: 15 May 2007 08:07:22
From: Helpful person
Subject: Re: New Televue Eyepice Design
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On May 15, 2:41 am, b...@isi.edu (Brian Tung) wrote:
> George Normandin wrote:
> > I didn't notice any pincushion when I looked thru it. However, all of the
> > stuff in the target was round - no straight lines. You can read on the
> > Televue website that the eyepiece fully corrects for "magnification
> > distortion", and thus planets are the correct shape through out the field.
> > However, as a result, they could not correct for pincushion since an
> > eyepiece can only correct for one distortion, not both...... or at least
> > that's how I read the Televue write-up.
>
> Pincushion distortion is a kind of magnification distortion: It is a
> distortion in which magnification increases as one goes out from the
> center of the field of view. The opposite is barrel distortion, in
> which the magnification decreases as one goes out from the center.
>
> --
> Brian Tung <b...@isi.edu>
> The Astronomy Corner athttp://astro.isi.edu/
> Unofficial C5+ Home Page athttp://astro.isi.edu/c5plus/
> The PleiadAtlas Home Page athttp://astro.isi.edu/pleiadatlas/
> My Own Personal FAQ (SAA) athttp://astro.isi.edu/reference/faq.html
Brian is correct. In addition, as distortion can be considered
spherical aberration of the pupil, it is most certainly possible to
correct it. (This is often not done to allow aberration correction of
other aberrations.)
Please visit my web site at www.richardfisher.com
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Date: 16 May 2007 02:26:47
From: George Normandin
Subject: Re: New Televue Eyepice Design
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"Helpful person" < > wrote
>
> Brian is correct......
Then I take it you guys are disagreeing with Al Nagler and the optics text
that he quotes (see
http://www.televue.com/includes/Article_Ethos_Intro_tech.asp) relative to
the two types of distortion being different and not controllable at the same
time? You are thus claiming that the Ethos could have been designed to
correct for both types of distortion even though Nagler says it can't be
done?
George N
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Date: 16 May 2007 00:10:31
From: Brian Tung
Subject: Re: New Televue Eyepice Design
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George Normandin wrote:
> Then I take it you guys are disagreeing with Al Nagler and the optics text
> that he quotes (see
> http://www.televue.com/includes/Article_Ethos_Intro_tech.asp) relative to
> the two types of distortion being different and not controllable at the same
> time? You are thus claiming that the Ethos could have been designed to
> correct for both types of distortion even though Nagler says it can't be
> done?
You misunderstand. They are not different types of distortion in the
sense that they have different causes--they both result from variations
in magnification with off-axis angle. They are simply two different
yardsticks by which to measure that magnification. Since the yardsticks
are different, you naturally cannot match both at the same time.
By way of analogy, suppose I ask you what's exactly halfway in between a
car that gets 10 mpg and one that gets 40 mpg. You *might* simply say
that it's a car that gets 25 mpg, since 25 is halfway between 10 mpg and
40 mpg. Or, you might recognize that the first car needs 40 gallons to
go 400 miles, and the latter just 10 gallons, and one that's halfway
should need 25 gallons--that's a car that gets 16 mpg. Or, you might
say that it's a car that gets 20 mpg, since that car would be half as
efficient as the 40 mpg car, but twice as efficient as the 20 mpg car.
They're all mpg, it's not as though it's a different way to express a
car's fuel efficiency, but they are different ways to judge what
"halfway" means for mpg. By the same token, what Al is calling zero
rectilinear distortion and zero angular distortion are just different
ways to judge what "distortion-free" means. It's not that one has to do
with magnification and one doesn't; it's that they're different ways to
rate the distortion, and they can't both be zero at the same time.
--
Brian Tung <brian@isi.edu >
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.html
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Date: 20 May 2007 01:45:18
From: Odysseus
Subject: Re: New Televue Eyepice Design
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In article <f2eap7$5np$1@praesepe.isi.edu >, brian@isi.edu (Brian Tung)
wrote:
<snip >
> [...] By the same token, what Al is calling zero rectilinear
> distortion and zero angular distortion are just different ways to
> judge what "distortion-free" means. It's not that one has to do with
> magnification and one doesn't; it's that they're different ways to
> rate the distortion, and they can't both be zero at the same time.
I suppose one could compare it to map projection, where such desirable
properties as conformity and equidistance are mutually exclusive, and
the choice among compromises is determined by the particular application
intended.
--
Odysseus
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Date: 19 May 2007 18:44:16
From: Brian Tung
Subject: Re: New Televue Eyepice Design
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I (Brian Tung) wrote:
> [...] By the same token, what Al is calling zero rectilinear
> distortion and zero angular distortion are just different ways to
> judge what "distortion-free" means. It's not that one has to do with
> magnification and one doesn't; it's that they're different ways to
> rate the distortion, and they can't both be zero at the same time.
Odysseus wrote:
> I suppose one could compare it to map projection, where such desirable
> properties as conformity and equidistance are mutually exclusive, and
> the choice among compromises is determined by the particular application
> intended.
That is a *great* example. Precisely.
--
Brian Tung <brian@isi.edu >
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.html
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Date: 17 May 2007 01:10:28
From: George Normandin
Subject: Re: New Televue Eyepice Design
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"Brian Tung" < > wrote
...
> George Normandin wrote:
>> Then I take it you guys are disagreeing with Al Nagler and the optics
>> text
>> that he quotes (see
>> http://www.televue.com/includes/Article_Ethos_Intro_tech.asp) relative to
>> the two types of distortion being different and not controllable at the
>> same
>> time? You are thus claiming that the Ethos could have been designed to
>> correct for both types of distortion even though Nagler says it can't be
>> done?
>
> You misunderstand. They are not different types of distortion in the
> sense that they have different causes--they both result from variations
> in magnification with off-axis angle..........
Brian,
OK...... I see your point. I can also see why the Ethos is designed the
way it is as a superior astronomy eyepiece versus a terrestrial eyepiece.
George N
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Date: 10 May 2007 20:57:23
From: thad@thadlabs.com
Subject: Re: New Televue Eyepice Design
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On May 10, 6:12 pm, "George Normandin" <georg...@worldnet.att.net >
wrote:
> "Alan French" <> wrote
> [...]
> I think Al Nagler will need to use a mini-black hole as one of the lens
> elements to get a 360 degree field of view - although I'm not sure why
> someone would want to see what's behind them! As far as 'myth', wasn't
> there someone in Greek mythology who could see coming and going?
In a not surprising merger of technologies, Meade, Nikon and Lens
Babies combined their expertise in optics, perspective control, and
selective focus, respectively, to produce the Meade Advanced Model
9000 Super360 series of 360 degree oculars effectively putting a
James Webb Telescope in your backyard!
Now anyone can easily view or image the farside of the Moon, look
around corners, and monitor the bald spot on top of your head!
Series 9000 product debut will be at this year's RTMC on May 25. An
advance press product photo is here:
<http://thadlabs.com/ASTRO/PIX/M9000_Super360_Plossl.jpg >
Yeah, cloudy skies tonight, but at least I got to use one of my scopes
for the picture. :-)
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Date: 04 May 2007 18:42:44
From: james
Subject: Re: New Televue Eyepice Design
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On Sat, 28 Apr 2007 19:24:14 -0400, "Dennis Woos" <dpwoos@gmavt.net >
wrote:
>+++In a talk my older son and I once gave at a club meeting, we compared the
>+++characteristics of a 20mm 50degree afov plossl to that of a hypothetical
>+++20mm 100degree afov "super Nagler". Well, I just got back from NEAF
>+++(NorthEast Astronomy Forum) where Al Nagler announced and demonstrated a new
>+++100 degree 13mm eyepiece! The field was much wider than an 82dgree Nagler,
>+++and one could only see the field stop with considerable effort. The
>+++question is, what do folks think is the market for such an eyepiece? Do any
>+++Nagler owners find 82degrees limiting? Is 100degrees really useful?
>+++
***********
Looks like AL has reached his quest to make a tripple digit field of
view eyepiece. I wonder how may lenses and at what cost?
In my opinion 100 degree field of view is good for looking at large
deep space objects at relatively low magnification. For planetary work
I would not consider this. Ultra wide eyepieces have their use. So
does narrow field of view eyepieces. It all depends on the scope used
and what you want to look at.
james
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Date: 10 May 2007 02:18:18
From: George Normandin
Subject: Re: New Televue Eyepice Design
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"james" < > wrote
>>+++..question is, what do folks think is the market for such an eyepiece?
>>Do any
>>+++Nagler owners find 82degrees limiting? Is 100degrees really useful?
>>+++
> ***********
>
> Looks like AL has reached his quest to make a tripple digit field of
> view eyepiece. I wonder how may lenses and at what cost?
>
> In my opinion 100 degree field of view is good for looking at large
> deep space objects at relatively low magnification. For planetary work
> I would not consider this. Ultra wide eyepieces have their use. So
> does narrow field of view eyepieces. It all depends on the scope used
> and what you want to look at.
>
James, et al:
The prototype at NEAF was a pretty sharp eyepiece. I could see the fibers
in the target card equally well at the center and extreme edge of the field.
I'll get one because I like high power and big field. I use a number of
different scopes but this eyepiece would work best with my Obsession 20 (no
drive) and A-P 6" F/12. Even with a Nagler the 'drift time' is short on the
20, and the field is small with an F/12 refractor. This eyepiece will help
with both "problems".
When will Televue sell a 360 degree eyepiece??? :)
George N
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Date: 10 May 2007 11:57:57
From: Alan French
Subject: Re: New Televue Eyepice Design
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"George Normandin" <georgepn@worldnet.att.net > wrote in message
news:Khv0i.3364$yM2.1638@bgtnsc04-news.ops.worldnet.att.net...
>
> When will Televue sell a 360 degree eyepiece??? :)
>
George N,
Aren't you talking about the mythical "zero power finder?"
Clear skies, Alan
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Date: 10 May 2007 22:45:04
From: Brian Tung
Subject: Re: New Televue Eyepice Design
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Alan French wrote:
> Aren't you talking about the mythical "zero power finder?"
I have that patented. However, I am not about making money from my
inventions (at least not this one), so I am including one for free in
each copy of my post. You can find your sample, for unlimited use,
embedded in the period at the end of this sentence.
--
Brian Tung <brian@isi.edu >
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.html
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Date: 11 May 2007 08:42:35
From: Alan French
Subject: Re: New Televue Eyepice Design
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"Brian Tung" <brian@isi.edu > wrote in message
news:f20vt0$s71$1@praesepe.isi.edu...
> Alan French wrote:
> > Aren't you talking about the mythical "zero power finder?"
>
> I have that patented. However, I am not about making money from my
> inventions (at least not this one), so I am including one for free in
> each copy of my post. You can find your sample, for unlimited use,
> embedded in the period at the end of this sentence.
Shouldn't I need a solar filter to safely read it during the day?
Clear skies, Alan
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Date: 11 May 2007 08:04:27
From: Howard Lester
Subject: Re: New Televue Eyepice Design
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"Alan French" wrote
>> I have that patented. However, I am not about making money from my
>> inventions (at least not this one), so I am including one for free in
>> each copy of my post. You can find your sample, for unlimited use,
>> embedded in the period at the end of this sentence.
> Shouldn't I need a solar filter to safely read it during the day?
Yes, as long as it's an APO.
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Date: 11 May 2007 01:12:14
From: George Normandin
Subject: Re: New Televue Eyepice Design
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"Alan French" < > wrote
...
>
>>
>> When will Televue sell a 360 degree eyepiece??? :)
>>
> George N,
>
> Aren't you talking about the mythical "zero power finder?"
>
Alan,
I think Al Nagler will need to use a mini-black hole as one of the lens
elements to get a 360 degree field of view - although I'm not sure why
someone would want to see what's behind them! As far as 'myth', wasn't
there someone in Greek mythology who could see coming and going?
George N
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Date: 11 May 2007 04:24:40
From: lal_truckee
Subject: Re: New Televue Eyepice Design
|
George Normandin wrote:
>
> I think Al Nagler will need to use a mini-black hole as one of the lens
> elements to get a 360 degree field of view - although I'm not sure why
> someone would want to see what's behind them! As far as 'myth', wasn't
> there someone in Greek mythology who could see coming and going?
Janus? He's Roman.
AFAIK no equivalent Greek predecessor.
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Date: 11 May 2007 20:49:23
From: William Hamblen
Subject: Re: New Televue Eyepice Design
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On Fri, 11 May 2007 04:24:40 GMT, lal_truckee <lal_truckee@yahoo.com >
wrote:
>George Normandin wrote:
>>
>> I think Al Nagler will need to use a mini-black hole as one of the lens
>> elements to get a 360 degree field of view - although I'm not sure why
>> someone would want to see what's behind them! As far as 'myth', wasn't
>> there someone in Greek mythology who could see coming and going?
>
>Janus? He's Roman.
>AFAIK no equivalent Greek predecessor.
Argus could see you coming and going with his one hundred eyes.
Bud
--
The night is just the shadow of the Earth.
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Date: 03 May 2007 09:54:15
From: Rich
Subject: Re: New Televue Eyepice Design
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On May 1, 11:51 am, W. H. Greer <sendnom...@tome.net > wrote:
> On 1 May 2007, "t...@thadlabs.com" wrote:
>
> >Though I used to have to do it (starhopping), today that's about as
> >archaic as cave painting.
>
> For some people, star-hopping is a pleasurable activity.
>
> >Do yourself a favor and get a GOTO mount/scope and join the 21st
> >century.
>
> Some have reasons to *not* use the technology that are just as good as
> the reasons that others have *to* use the technology.
>
> >With today's light pollution, star hopping is increasingly difficult
> >and I don't see the situation improving anytime soon.
>
> Some observe from darker skies. Some observe from brighter skies.
> Light pollution has not had the same impact on everyone.
> --
> Bill
95% of the country live in urban, light-polluted areas, though some
can travel fairly short distances to dark skies.
Water vapour is the enemy. In a North Eastern city, you have to
travel 100+ miles to avoid the light pollution due to the water vapour
in the air, but in a dry climate (near Los Angeles) you can drive
about 30-40 miles and have reasonably dark skies.
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Date: 02 May 2007 05:05:38
From:
Subject: Re: New Televue Eyepice Design
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> It's not too bad a feature of the human eye however - unless you
> want to argue with evolution :- )
My apologies. I should clarify - We see the whole field, but no
field "edge"
H
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Date: 02 May 2007 03:27:55
From:
Subject: Re: New Televue Eyepice Design
|
Tom Polakis wrote:
>howieglat...@mindspring.com wrote:
> > . . As close as I could get to the eyelens, I could not see the entire
> > field by looking straight ahead...
> I may change my mind after I look through one, but I don't consider
> this to be a desirable feature in an eyepiece.
It's not too bad a feature of the human eye however - unless you
want to argue with evolution :- )
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Date: 01 May 2007 15:26:36
From: Tom Polakis
Subject: Re: New Televue Eyepice Design
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Dennis Woos wrote:
> Well, I just got back from NEAF
> (NorthEast Astronomy Forum) where Al Nagler announced and demonstrated a new
> 100 degree 13mm eyepiece!
I'm looking forward to the release of Meade's 102-degree eyepiece.
Tom
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Date: 01 May 2007 19:10:30
From: Alan French
Subject: Re: New Televue Eyepice Design
|
"Tom Polakis" <polakisgroups@cox.net > wrote in message
news:1178058396.348593.68650@e65g2000hsc.googlegroups.com...
>
> Dennis Woos wrote:
> > Well, I just got back from NEAF
> > (NorthEast Astronomy Forum) where Al Nagler announced and demonstrated a
new
> > 100 degree 13mm eyepiece!
>
>
> I'm looking forward to the release of Meade's 102-degree eyepiece.
Tom,
Funny. I said the same thing to Sue.
Clear skies, Alan
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Date: 02 May 2007 01:13:29
From: George Normandin
Subject: Re: New Televue Eyepice Design
|
"Alan French" < > wrote
>>
>>
>> I'm looking forward to the release of Meade's 102-degree eyepiece.
>
>
> Funny. I said the same thing to Sue.
> .....
As I mentioned in an earlier post, late on Sunday the Meade guys were
standing around talking to the Televue guys. One said that he intends to buy
an Ethos as soon as it is available for sale - probably to take apart and
see how it works! :)
George N
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Date: 01 May 2007 15:24:46
From: Tom Polakis
Subject: Re: New Televue Eyepice Design
|
On May 1, 4:31 am, howieglat...@mindspring.com wrote:
> Dennis Woos wrote:
> > . .The field was much wider than an 82dgree Nagler,
> > and one could only see the field stop with considerable effort . .
>
> As close as I could get to the eyelens, I could not see the entire
> field by looking straight ahead...
I may change my mind after I look through one, but I don't consider
this to be a desirable feature in an eyepiece. If TeleVue has pulled
of a sharp-to-the-edge eyepiece with a 100-degree field, more power to
them, but my personal preference is to be able to see everything in
the circle without having to make my eye wander around. I am just
barely able to do this in the 82-degree diameter of the Nagler's
field, so I've always considered it a practical upper limit.
Think of the money I'll save!
Tom
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Date: 02 May 2007 01:20:24
From: George Normandin
Subject: Re: New Televue Eyepice Design
|
"Tom Polakis" < > wrote
>>.......
>> As close as I could get to the eyelens, I could not see the entire
>> field by looking straight ahead...
>
>
> I may change my mind after I look through one, but I don't consider
> this to be a desirable feature in an eyepiece.......
I hope you don't change your mind Tom, 'cuz then I'll have one less person
in front of me when I'm trying to buy two of these for my bino-viewer just
as soon as they go up for sale! :)
George N
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Date: 01 May 2007 10:55:08
From: Dave Mitsky
Subject: Re: New Televue Eyepice Design
|
On Apr 28, 7:24 pm, "Dennis Woos" <dpw...@gmavt.net > wrote:
> In a talk my older son and I once gave at a club meeting, we compared the
> characteristics of a 20mm 50degree afov plossl to that of a hypothetical
> 20mm 100degree afov "super Nagler". Well, I just got back from NEAF
> (NorthEast Astronomy Forum) where Al Nagler announced and demonstrated a new
> 100 degree 13mm eyepiece! The field was much wider than an 82dgree Nagler,
> and one could only see the field stop with considerable effort. The
> question is, what do folks think is the market for such an eyepiece? Do any
> Nagler owners find 82degrees limiting? Is 100degrees really useful?
>
> I didn't get one, and not because they are not yet for sale. I did get,
> courtesy of Televue, a TV 32mm plossl, a TV 20mm plossl, and a TV 2x barlow
> for $75 in total, which I will give to my son as a graduation present. He
> can use these with one of our scopes (6" f/8 dob) when he starts college
> this fall, and get in some observing time. He intends to major in
> Physics/AstroPhysics!
>
> Dennis
I had a long look through the new Tele Vue prototype Ethos eyepiece.
It's a 1.25"/2" hybrid barrel 13mm with a 100 degree apparent field of
view (AFOV).
The field of view and rectilinearity of the Ethos were really quite
amazing. Of course, Uncle Al declined to answer questions about the
design for proprietary reasons.
After comparing the delineated AFOV boundaries, 82 degrees just
doesn't seem so big anymore!
Tele Vue employee Paul Dellechiaie was apparently responsible for much
of the design. Information on the Ethos is available at
http://www.televue.com/engine/page.asp?ID=311
Dave Mitsky
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Date: 01 May 2007 04:31:33
From:
Subject: Re: New Televue Eyepice Design
|
Dennis Woos wrote:
> . .The field was much wider than an 82dgree Nagler,
> and one could only see the field stop with considerable effort . .
As close as I could get to the eyelens, I could not see the entire
field by looking straight ahead. I could see to the edges of the field
however by looking sideways towards the edges. It was sharp to the
edge ! I found this to be a unique and enjoyable experience, and would
love to try it on a real astronomical vista, as opposed to the test
target (which was very nice and well thought out by the way).
It was truly a "porthole" experience. My hat is of to Paul, who
designed it.
Howie
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Date: 11 May 2007 14:38:56
From: Llanzlan Klazmon the 15th
Subject: Re: New Televue Eyepice Design
|
howieglatter@mindspring.com wrote in news:1178019093.481616.140690
@h2g2000hsg.googlegroups.com:
> Dennis Woos wrote:
>> . .The field was much wider than an 82dgree Nagler,
>> and one could only see the field stop with considerable effort . .
>
> As close as I could get to the eyelens, I could not see the entire
> field by looking straight ahead. I could see to the edges of the field
> however by looking sideways towards the edges. It was sharp to the
> edge ! I found this to be a unique and enjoyable experience, and would
> love to try it on a real astronomical vista, as opposed to the test
> target (which was very nice and well thought out by the way).
> It was truly a "porthole" experience. My hat is of to Paul, who
> designed it.
>
> Howie
What is the distortion like. Is there noticable pincushion?
Klazmon.
>
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Date: 01 May 2007 03:49:12
From:
Subject: Re: New Televue Eyepice Design
|
On May 1, 4:52 am, "t...@thadlabs.com" <t...@thadlabs.com > wrote:
> On May 1, 1:43 am, Sam Wormley <sworml...@mchsi.com> wrote:
>
> > Dennis Woos wrote:
> > > In a talk my older son and I once gave at a club meeting, we compared the
> > > characteristics of a 20mm 50degree afov plossl to that of a hypothetical
> > > 20mm 100degree afov "super Nagler". Well, I just got back from NEAF
> > > (NorthEast Astronomy Forum) where Al Nagler announced and demonstrated a new
> > > 100 degree 13mm eyepiece! The field was much wider than an 82dgree Nagler,
> > > and one could only see the field stop with considerable effort. The
> > > question is, what do folks think is the market for such an eyepiece? Do any
> > > Nagler owners find 82degrees limiting? Is 100degrees really useful?
>
> > Without experiencing such an eyepiece, I can only speculate, but I
> > suspect the wider AFOV would be beneficial for star hopping.
>
> Though I used to have to do it (starhopping), today that's about as
> archaic as
> cave painting.
I guess visual observing must be archaic as well.
>
> Do yourself a favor and get a GOTO mount/scope and join the 21st
> century.
>
> With today's light pollution, star hopping is increasingly difficult
> and I don't
> see the situation improving anytime soon.
A good 60 to 80mm finder with a wide AFOV eyepiece, along with good
charts, makes starhopping easy, even with light pollution.
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Date: 01 May 2007 01:52:29
From: thad@thadlabs.com
Subject: Re: New Televue Eyepice Design
|
On May 1, 1:43 am, Sam Wormley <sworml...@mchsi.com > wrote:
> Dennis Woos wrote:
> > In a talk my older son and I once gave at a club meeting, we compared the
> > characteristics of a 20mm 50degree afov plossl to that of a hypothetical
> > 20mm 100degree afov "super Nagler". Well, I just got back from NEAF
> > (NorthEast Astronomy Forum) where Al Nagler announced and demonstrated a new
> > 100 degree 13mm eyepiece! The field was much wider than an 82dgree Nagler,
> > and one could only see the field stop with considerable effort. The
> > question is, what do folks think is the market for such an eyepiece? Do any
> > Nagler owners find 82degrees limiting? Is 100degrees really useful?
>
> Without experiencing such an eyepiece, I can only speculate, but I
> suspect the wider AFOV would be beneficial for star hopping.
Though I used to have to do it (starhopping), today that's about as
archaic as
cave painting.
Do yourself a favor and get a GOTO mount/scope and join the 21st
century.
With today's light pollution, star hopping is increasingly difficult
and I don't
see the situation improving anytime soon.
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Date: 01 May 2007 17:12:58
From: Sam Wormley
Subject: Re: New Televue Eyepice Design
|
thad@thadlabs.com wrote:
> On May 1, 1:43 am, Sam Wormley <sworml...@mchsi.com> wrote:
>> Dennis Woos wrote:
>>> In a talk my older son and I once gave at a club meeting, we compared the
>>> characteristics of a 20mm 50degree afov plossl to that of a hypothetical
>>> 20mm 100degree afov "super Nagler". Well, I just got back from NEAF
>>> (NorthEast Astronomy Forum) where Al Nagler announced and demonstrated a new
>>> 100 degree 13mm eyepiece! The field was much wider than an 82dgree Nagler,
>>> and one could only see the field stop with considerable effort. The
>>> question is, what do folks think is the market for such an eyepiece? Do any
>>> Nagler owners find 82degrees limiting? Is 100degrees really useful?
>> Without experiencing such an eyepiece, I can only speculate, but I
>> suspect the wider AFOV would be beneficial for star hopping.
>
> Though I used to have to do it (starhopping), today that's about as
> archaic as
> cave painting.
>
> Do yourself a favor and get a GOTO mount/scope and join the 21st
> century.
>
> With today's light pollution, star hopping is increasingly difficult
> and I don't
> see the situation improving anytime soon.
>
My own observing makes use of goto mount much of the time, but when
working with students (where power and setup time are luxuries), I
need to find many DSOs via star hopping. It is a skill one should
always maintain.
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Date: 01 May 2007 10:08:22
From: Shawn
Subject: Re: New Televue Eyepice Design
|
thad@thadlabs.com wrote:
> On May 1, 1:43 am, Sam Wormley <sworml...@mchsi.com> wrote:
>> Dennis Woos wrote:
>>> In a talk my older son and I once gave at a club meeting, we compared the
>>> characteristics of a 20mm 50degree afov plossl to that of a hypothetical
>>> 20mm 100degree afov "super Nagler". Well, I just got back from NEAF
>>> (NorthEast Astronomy Forum) where Al Nagler announced and demonstrated a new
>>> 100 degree 13mm eyepiece! The field was much wider than an 82dgree Nagler,
>>> and one could only see the field stop with considerable effort. The
>>> question is, what do folks think is the market for such an eyepiece? Do any
>>> Nagler owners find 82degrees limiting? Is 100degrees really useful?
>> Without experiencing such an eyepiece, I can only speculate, but I
>> suspect the wider AFOV would be beneficial for star hopping.
>
> Though I used to have to do it (starhopping), today that's about as
> archaic as
> cave painting.
>
> Do yourself a favor and get a GOTO mount/scope and join the 21st
> century.
>
> With today's light pollution, star hopping is increasingly difficult
> and I don't
> see the situation improving anytime soon.
Bull! Maybe not if you live where six visible stars is a good night. I
live in a 'burb of a metro area with 3M people and can star hop fine.
Why should I pay for electronics I don't need, when I can buy more
aperture instead?
Shawn
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Date: 01 May 2007 09:51:20
From: W. H. Greer
Subject: Re: New Televue Eyepice Design
|
On 1 May 2007, "thad@thadlabs.com" wrote:
>Though I used to have to do it (starhopping), today that's about as
>archaic as cave painting.
For some people, star-hopping is a pleasurable activity.
>Do yourself a favor and get a GOTO mount/scope and join the 21st
>century.
Some have reasons to *not* use the technology that are just as good as
the reasons that others have *to* use the technology.
>With today's light pollution, star hopping is increasingly difficult
>and I don't see the situation improving anytime soon.
Some observe from darker skies. Some observe from brighter skies.
Light pollution has not had the same impact on everyone.
--
Bill
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Date: 01 May 2007 08:43:01
From: Sam Wormley
Subject: Re: New Televue Eyepice Design
|
Dennis Woos wrote:
> In a talk my older son and I once gave at a club meeting, we compared the
> characteristics of a 20mm 50degree afov plossl to that of a hypothetical
> 20mm 100degree afov "super Nagler". Well, I just got back from NEAF
> (NorthEast Astronomy Forum) where Al Nagler announced and demonstrated a new
> 100 degree 13mm eyepiece! The field was much wider than an 82dgree Nagler,
> and one could only see the field stop with considerable effort. The
> question is, what do folks think is the market for such an eyepiece? Do any
> Nagler owners find 82degrees limiting? Is 100degrees really useful?
Without experiencing such an eyepiece, I can only speculate, but I
suspect the wider AFOV would be beneficial for star hopping.
>
> I didn't get one, and not because they are not yet for sale. I did get,
> courtesy of Televue, a TV 32mm plossl, a TV 20mm plossl, and a TV 2x barlow
> for $75 in total, which I will give to my son as a graduation present. He
> can use these with one of our scopes (6" f/8 dob) when he starts college
> this fall, and get in some observing time. He intends to major in
> Physics/AstroPhysics!
>
> Dennis
>
>
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Date: 30 Apr 2007 01:24:31
From:
Subject: Re: New Televue Eyepice Design
|
Hi all,
Here in Switzerland, this "Ethos" eyepiece (13 mm, 100 degrees FOV)
has been announced by our main astrogear reseller, and the indicative
price tag is at 900 CHF, which puts it in the same category than the
Naglers 26 and 31 (which sell here for between 900 and 1000 CHF). Not
cheap, but no more expensive than the 2 aforementioned grenades.
Cheers, Pierre in Lausanne
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Date: 28 Apr 2007 17:23:44
From: RMOLLISE
Subject: Re: New Televue Eyepice Design
|
On Apr 28, 6:24 pm, "Dennis Woos" <dpw...@gmavt.net > wrote:
> In a talk my older son and I once gave at a club meeting, we compared the
> characteristics of a 20mm 50degree afov plossl to that of a hypothetical
> 20mm 100degree afov "super Nagler". Well, I just got back from NEAF
> (NorthEast Astronomy Forum) where Al Nagler announced and demonstrated a new
> 100 degree 13mm eyepiece! The field was much wider than an 82dgree Nagler,
> and one could only see the field stop with considerable effort. The
> question is, what do folks think is the market for such an eyepiece? Do any
> Nagler owners find 82degrees limiting? Is 100degrees really useful?
>
> I didn't get one, and not because they are not yet for sale. I did get,
> courtesy of Televue, a TV 32mm plossl, a TV 20mm plossl, and a TV 2x barlow
> for $75 in total, which I will give to my son as a graduation present. He
> can use these with one of our scopes (6" f/8 dob) when he starts college
> this fall, and get in some observing time. He intends to major in
> Physics/AstroPhysics!
>
> Dennis
HI Dennis:
Didn't think I'd ever sell my Type II 12mm...but this just might make
me do it...if the price ain't _too_ insane. :-)
Unk Rod
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Date: 28 Apr 2007 22:21:30
From: Dennis Woos
Subject: Re: New Televue Eyepice Design
|
> Didn't think I'd ever sell my Type II 12mm...but this just might make
> me do it...if the price ain't _too_ insane. :-)
>
Al Nagler either could not or would not say how much it would sell for, but
he did say that it would be available in the next few months.
He said that he co-designed it with another fellow, who I have never seen
before and who was present. Later on, I had the occasion to talk with this
other guy and ask him a couple of questions about the design of the
eyepiece. I asked if there was anything about the eyepeice such that it
couldn't have been made 20 years ago, i.e. some technical breakthrough like
exotic glass. He said not. He did say that optimization software was
extremely important in coming up with the design. As I have never used
optical design software, it was enlightening to learn that optical design is
largely a process of searching for solutions that satisfy a set of criteria,
and not simply a matter of solving equations. One can see where more
computer horsepower allows a deeper and wider search, and so makes it more
likely that a good design is found. Perhaps someone who has knowledge of
optical design can comment on the process?
Dennis
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Date: 01 May 2007 03:38:29
From: George Normandin
Subject: Re: New Televue Eyepice Design
|
"Dennis Woos" < > wrote
> ......
> Al Nagler either could not or would not say how much it would sell for,
> but he did say that it would be available in the next few months.
> ........
A friend of mine claims that he got "about $500" out of one of the Televue
crew. Personally, I plan on winning one at the Stellafane raffle! :)
When I was at the Televue area late on Sunday the Meade representative was
talking to the Televue guys and a few others. As I was walking up he was
saying: "We have excellent wide-field eyepieces, but nothing like this! If
it goes for less than a grand I'll buy one!" It's nice when your competitors
complement you.
George N
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Date: 28 Apr 2007 20:10:01
From: Steve Sherman
Subject: Re: New Televue Eyepice Design
|
Dennis Woos wrote:
> In a talk my older son and I once gave at a club meeting, we compared the
> characteristics of a 20mm 50degree afov plossl to that of a hypothetical
> 20mm 100degree afov "super Nagler". Well, I just got back from NEAF
> (NorthEast Astronomy Forum) where Al Nagler announced and demonstrated a new
> 100 degree 13mm eyepiece! The field was much wider than an 82dgree Nagler,
> and one could only see the field stop with considerable effort. The
> question is, what do folks think is the market for such an eyepiece? Do any
> Nagler owners find 82degrees limiting? Is 100degrees really useful?
>
> I didn't get one, and not because they are not yet for sale. I did get,
> courtesy of Televue, a TV 32mm plossl, a TV 20mm plossl, and a TV 2x barlow
> for $75 in total, which I will give to my son as a graduation present. He
> can use these with one of our scopes (6" f/8 dob) when he starts college
> this fall, and get in some observing time. He intends to major in
> Physics/AstroPhysics!
>
> Dennis
>
>
In most cases the bottom line is to get higher magnification and not
lose the field of view. The field of view in a 10" F/10 SCT
is not much to start with, so every little bit counts.
If you want a 3 degree field of view, you need all the help
you can get. Is a 100 degree eyepiece needed?
Well, more than I need a iPod..
Steve
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Date: 28 Apr 2007 23:57:34
From: George Normandin
Subject: Re: New Televue Eyepice Design
|
"Dennis Woos" < > wrote
...
> ......I just got back from NEAF
> (NorthEast Astronomy Forum) where Al Nagler announced and demonstrated a
> new
> 100 degree 13mm eyepiece.......
Now Televue should make binoculars using two of their 101mm telescopes and
these eyepieces, mounted on a motorized observing chair!
......but seriously, I'd consider buying two of these new eyepieces to
use in a binoviewer.
George N
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Date: 29 Apr 2007 02:48:20
From: Anthony Ayiomamitis
Subject: Re: New Televue Eyepice Design
|
Dennis Woos wrote:
> In a talk my older son and I once gave at a club meeting, we compared the
<snip >
> this fall, and get in some observing time. He intends to major in
> Physics/AstroPhysics!
Speaking of "AstroPhysics", there were apparently two new models on
display and both were oil-spaced triplets. We now have an AP130/f6.3 and
an AP140/f7.5.
Anthony.
PS. I realize it is "Astro-Physics" ... so no flames please. :-)
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