New 31mm Nagler: Upgrade Paracorr?

Hi all,

I bought a photo-visual Paracorr last year on Astromart as an
accessory for my f4.5 13" dob. I assumed that I would not be getting a
31mm Nagler anytime soon, so this seemed like a good choice. Well, a
31mm Nagler will be landing in my EP case shortly thanks to my
brother. Is the difference great enough between the photo-visual and
visual-only models to make a noticeable difference when observing with
the 31mm? Is it upgrade time again...?

Thanks for any and all input,

- Craig

Craig Levine
Observing Chairman
RASC, Halifax Centre
www.halifax.rasc.ca

Subject: New 31mm Nagler: Upgrade Paracorr?
From: Craig Levine
Date: 2/26/04 4:07 PM Pacific Standard Time
Message-id:

Hi all,

I bought a photo-visual Paracorr last year on Astromart as an
accessory for my f4.5 13" dob. I assumed that I would not be getting a
31mm Nagler anytime soon, so this seemed like a good choice. Well, a
31mm Nagler will be landing in my EP case shortly thanks to my
brother. Is the difference great enough between the photo-visual and
visual-only models to make a noticeable difference when observing with
the 31mm? Is it upgrade time again...?

Thanks for any and all input,

- Craig
************************
I use the older Paracor, with my Dob, anything below f4.5 you really need
the Paracor! I have the 31mm, 26,22 &17mm Nags, i use the Paracor for low
power work, and for high power work above 150x to 1100x i dont need the
Paracor.

So if coma bothers you then the Paracor would be needed with the 31mm Nag!
And the Paracor you have will work fine...

Chas P.

Is the difference great enough between the photo-visual and
visual-only models to make a noticeable difference when observing with
the 31mm

Hi...

I'm not certain what you mean when you say a "photo-visual" version of the
ParaCorr, but I'm assuming you just mean the non-adjustable model.
The 31mm Nagler works best when the 'tunatable' top is at its' innermost
position.
If, in the version you have, the distance between the field lens of the
eyepiece and the lens of the ParaCorr is longer than this minimum distance you
will not be getting the maximum performance from the 31mm.

Mike Harvey

On 27 Feb 2004 18:40:06 GMT, (MHarveyWW1) wrote:

I'm not certain what you mean when you say a "photo-visual" version of the
ParaCorr, but I'm assuming you just mean the non-adjustable model.
The 31mm Nagler works best when the 'tunatable' top is at its' innermost
position.
If, in the version you have, the distance between the field lens of the
eyepiece and the lens of the ParaCorr is longer than this minimum distance you
will not be getting the maximum performance from the 31mm.

Mike Harvey


Hi Mike,

There are two versions of the Paracorr. The one that I have has T-
threads for attaching a standard 35mm Camera. The optional items
available are the tunable top and 2" to 1.25 adapter which convert the
photographic Paracorr into a Visual Paracorr. The other version is the
"Visual Only", which is a complete unit with a larger field lens and
no T-threads. That model was designed for those with a Nagler 31mm, as
apparently some vignetting can be seen with the 31mm in the
Photo-Visual model. The heart of my cocern is, how noticeable is the
vignetting, and is it bad enough that I should get the visual-only
model, or is it subtle enough to let me use trhe model that I have.

Cheers,

- Craig

Craig Levine
Observing Chairman
RASC, Halifax Centre
www.halifax.rasc.ca

Hi Mike,

There are two versions of the Paracorr. The one that I have has T-
threads for attaching a standard 35mm Camera. The optional items
available are the tunable top and 2" to 1.25 adapter which convert the
photographic Paracorr into a Visual Paracorr. The other version is the
"Visual Only", which is a complete unit with a larger field lens and
no T-threads. That model was designed for those with a Nagler 31mm, as
apparently some vignetting can be seen with the 31mm in the
Photo-Visual model. The heart of my cocern is, how noticeable is the
vignetting, and is it bad enough that I should get the visual-only
model, or is it subtle enough to let me use trhe model that I have.

Cheers,

- Craig

Craig Levine
***********************
I have the older version Paracorr, and i never noticed any vignetting, with my
31mm Nag! But then again i never looked for vignetting. But i will try it out
next time i get the scope out...

Chas P.

There are two versions of the Paracorr.

Hello, again...

yes, I know there are two versions, but I've never heard the non-tunable-top
referred to as the 'photo-visual' model. I think we're talking about the same
thing, though.
When I first purchased the 31mm Nagler I still had the 'original' (non-tunable)
ParaCorr. It seemed to work just fine.
THEN, Al Nagler suggested I try the tunable-top with the eyepiece and,
voila'...
suddenly I realized I had not been getting the full effect!
Is the difference enough to warrant buying a new ParaCorr? I thought so.

Mike Harvey

In article ,
Craig Levine wrote:



There are two versions of the Paracorr. The one that I have has T-
threads for attaching a standard 35mm Camera. The optional items
available are the tunable top and 2" to 1.25 adapter which convert the
photographic Paracorr into a Visual Paracorr. The other version is the
"Visual Only", which is a complete unit with a larger field lens and
no T-threads. That model was designed for those with a Nagler 31mm, as
apparently some vignetting can be seen with the 31mm in the
Photo-Visual model. The heart of my cocern is, how noticeable is the
vignetting, and is it bad enough that I should get the visual-only
model, or is it subtle enough to let me use trhe model that I have.



Craig,

Why don't you go to TeleVue's website and ask them your questions.
You're sure to get the straight poop there- free and accurate advice
about their products.

Starry Skies,
Rich

On Fri, 27 Feb 2004 20:20:42 GMT, Craig Levine
wrote:


There are two versions of the Paracorr. The one that I have has T-
threads for attaching a standard 35mm Camera. The optional items
available are the tunable top and 2" to 1.25 adapter which convert the
photographic Paracorr into a Visual Paracorr. The other version is the
"Visual Only", which is a complete unit with a larger field lens and
no T-threads. That model was designed for those with a Nagler 31mm, as
apparently some vignetting can be seen with the 31mm in the
Photo-Visual model. The heart of my cocern is, how noticeable is the
vignetting, and is it bad enough that I should get the visual-only
model, or is it subtle enough to let me use trhe model that I have.

Counting the original "non tunable top" model, there are actually 3
different Paracorrs in general use right now. Both the current
"photo/visual" and "visual only" models have the same tunable top, and a
tunable top can even be purchased separately and screwed onto the old
original model (after the original "solid top" section is first threaded
off), making it identical to the current photo/visual model. I believe
the photo/visual model has a "free aperture" of about 35mm or 36mm (just
enough to use the 35mm Panoptic without vignetting), and the visual only
model is right at 42mm of free aperture (matching the 42mm field stop of
the 31mm Nagler). The "visual only" Paracorr will still vignette the
truly widest field 2" eyepieces with their 44mm to 46mm field stops.

I once owned a (now very rare, quite hard to find, and expensive) 1.25"
Paracorr, but in a weak moment I sold it, and I have kicked myself for
doing so ever sense.

Lawrence Sayre
--
------------------------------------------------------------------------
My philosophy, in essence, is the concept of man as
a moral being, with his own happiness as the moral
purpose of his life, with productive achievement as
his noblest activity, and reason as his only absolute.

Ayn Rand (in the appendix to 'Atlas Shrugged')
------------------------------------------------------------------------

I have the older version Paracorr, and i never noticed any vignetting, with my
31mm Nag! But then again i never looked for vignetting. But i will try it out
next time i get the scope out...

Chas P.

Thanks Chas. Let me know what you see. I'll have my 31/Paracorr combo
out as soon as possible after the 31 arrives.

Cheers,

- Craig

On 28 Feb 2004 01:58:25 GMT, (MHarveyWW1) wrote:

There are two versions of the Paracorr.

Hello, again...

yes, I know there are two versions, but I've never heard the non-tunable-top
referred to as the 'photo-visual' model. I think we're talking about the same
thing, though.
When I first purchased the 31mm Nagler I still had the 'original' (non-tunable)
ParaCorr. It seemed to work just fine.
THEN, Al Nagler suggested I try the tunable-top with the eyepiece and,
voila'...
suddenly I realized I had not been getting the full effect!
Is the difference enough to warrant buying a new ParaCorr? I thought so.

Mike Harvey


Hi Mike,

The additon of the Tunable Top (Televue part # PTT-2002) turns the
Paracorr Photographic into the "Photo-Visual" model.

Cheers,

- Craig