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The world without Televue

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#251 25585

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Posted 22 September 2019 - 08:53 AM

I was very pleased to look through Al Nagler's NV eyepiece in his 101mm rerfractor at the NA Nebula 

at Stellafane his year. It was my first and only experience with NV. It was a wonderful experience but

not something I would seriously consider buying, at least at this time. However, in the past I've said the

same thing about Ethos eyepieces and Paracorr ll which I now own. You never know where the path will

take you. 

The price is steep. Had I the funds, I would buy a Tak or TV refractor first. Nice developed world dilemma...



#252 25585

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Posted 22 September 2019 - 09:25 AM

The innovation I would like to see is more along this line of thinking - what we need is a CCD eyepiece, not monochrome NV devices.

 

Look how small "smartphone" computers have become, with batteries, cameras, and monitors built-in.  Look at virtual-reality goggles in gaming. Let's take advantage of miniaturization of technology.

 

How about an ocular the size and weight of a 31mm Nagler that has a CCD chip and LCD monitor built-in.   You put the eyepiece into the focuser, look into it, and see a real-time, color image of the target.  You plug it into your USB charger to charge the battery up before each session.  

 

When I do outreach events I already have people holding their Iphones up to my eyepiece and taking pictures of Jupiter.   The next step seems obvious!

I believe that is much more the future. With night photography capabilities improving on smartphones, its in the near future they will be capable of showing more than the visual potential of any telescope. New phone contract due soon, I am looking into that as a major feature to sell me a model....

 

What is most appealing to me is that if eye relief is too short in an eyepiece wearing glasses, the whole FOV can be seen (& in more colour) afocally with an OLED display. Brightness, contrast, colour, touch screen zooming-in all benefits, and loads of other benefits.

 

Using a DSLR or mirrorless camera afocally, or not, inline with the OTA, flip screen up instead of a diagonal, gives RACI views & their display & photography settings offer more options than a cel phone currently.

 

Afocal needs large exit pupils, so longer focal length eyepieces, and longer eye relief I imagine. TV 35 Panoptic & 55 Plossl are fine, but not the 41 Panoptic with its current eye end design, an adaptor or re-design needs making. Do any NV users employ the 41 Pan?  



#253 25585

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Posted 22 September 2019 - 09:46 AM

If I wore tattoos, one would read TeleVue.

Not.

 

But..

Attached Thumbnails

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#254 Jeff Morgan

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Posted 22 September 2019 - 11:17 AM

Using a DSLR or mirrorless camera afocally, or not, inline with the OTA, flip screen up instead of a diagonal, gives RACI views & their display & photography settings offer more options than a cel phone currently.

 

Afocal needs large exit pupils, so longer focal length eyepieces, and longer eye relief I imagine. TV 35 Panoptic & 55 Plossl are fine, but not the 41 Panoptic with its current eye end design, an adaptor or re-design needs making. Do any NV users employ the 41 Pan?  

 

Definitely DSLRs (and dedicated astro cameras) give worlds better results.

 

But these days everybody already owns a smart phone. Just add a $100 adapter and a $4 app (for more access to the camera controls) and you are in business. It's very easy to do. Moon and planets are plenty bright.

 

The cell phone adapter goes onto the eyepiece fairly quickly and if you use Extra Dark Red Cling film on the iPhone screen it is possibly to mix it in with regular viewing, though I have drifted away from that myself. Still some disruption to observing, and my sessions are usually goal-oriented working through target lists. No time to mess around with the phone. More relaxed or casual observers may not find that to be an issue, YMMV.

 

On the afocal, Tele Vue says any Dioptrx capable eyepiece works.

 

WRT to the 41 Panoptic and NV, some people are doing this now:

 

https://www.cloudyni...-dob/?p=9594361

https://www.cloudyni...ield/?p=9659939

 

A beast of a set-up (imagine attaching a Delos to the end of a 41 Panoptic), but reported better edge correction than the 55 Plossl (which I use fairly often).


Edited by Jeff Morgan, 22 September 2019 - 11:17 AM.

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#255 25585

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Posted 22 September 2019 - 11:40 AM

I see Gavster is considering a Tak LE50. Maybe they have better attributes for afocal viewing.

 

Pentax XW 30 & 40 also have M43 threads. 



#256 nicoledoula

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Posted 22 September 2019 - 01:27 PM

Where would TV be without constant threads glorifying them? 


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#257 csrlice12

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Posted 22 September 2019 - 05:10 PM

Where would TV be without constant threads glorifying them? 

They would then be in the same place as the Pentax XWs....who relies on word of mouth, no fancy glossy ads.


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#258 John Huntley

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Posted 22 September 2019 - 06:09 PM

...Also no surprises like half of an eyepiece family having field curvature. I love the shorter XW's, but don't really want to take any more chances on the longer ones.

Agreed. This is why I use the Delos 14 and 17.3 and a 24 Panoptic alongside the Pentax XW's 10, 7, 5 and 3.5.


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#259 careysub

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Posted 22 September 2019 - 06:29 PM

Image Intensifiers are doing some of what you list right now.

 

And TV has dipped their toe into that market.

 

HERE is a link.

 

Bob

It is interesting to note how image intensifiers work, and compare that to how regular lenses work.

 

Do regular lenses show you the original photons emanating from the celestial object? No, and sort of yes. The photon path is bent by the glass because it is repeated absorbed and re-emitted with exactly the same properties, save for a slight change in its travel vector.

 

There is no test you could do that would reveal that it was not the original (assuming you could know the original state).

 

Image intensifiers convert the image, carried by photon quanta, to an image carried by electron quanta. It is not stored, detected, or analyzed in any way. This electron stream is amplified by acceleration, then strikes a microchannel plate that converts that energy into multiple electrons along the same path, which then gets converted back into photons at a phosphor screen.

 

The image is preserved in the stream of quanta from beginning to end. The original frequency of the electron is lost -- a good thing, if you want to take advantage of its deep red and infrared sensitivity.

 

It can reasonably be described as an "electron optics eyepiece".



#260 nva

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Posted 22 September 2019 - 06:48 PM

I didn't read the 11 pages of adulations did anyone else say "cheaper" yet?
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#261 Starman1

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Posted 22 September 2019 - 08:24 PM

Change your personal post-per-page number to 99 and you are only on page 3. 

LOL.

 

Given that the last 50 posts seem to be lauding the advantages of night vision devices (all of which make TeleVue eyepieces seem very inexpensive),

and that there are many brands of eyepieces more expensive than TeleVue, which also make TeleVue eyepieces seem inexpensive, I think it would be fair

to say that there would be one less brand of medium-priced eyepieces.

Of course, given that there are at least 3 levels of price for products, someone else would have filled the niche if TeleVue hadn't existed.

 

There's no guarantee that someone wouldn't have filled that niche with something lesser at the same prices, either.



#262 Jeff Morgan

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Posted 22 September 2019 - 09:53 PM

I didn't read the 11 pages of adulations did anyone else say "cheaper" yet?

 

Of course not. Tele Vue bore the R&D costs for Meade and ES.


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#263 alnitak22

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Posted 22 September 2019 - 10:05 PM

Of course not. Tele Vue bore the R&D costs for Meade and ES.

Yet so many seem unaware or don’t seem to care.


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#264 carl_g

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Posted 24 September 2019 - 08:51 PM



Amateur astronomy is an incredibly small niche, and (as a group) we are notoriously cheap. I doubt one of the big optical companies with small astronomy units (Nikon, Pentax, Zeiss for example) would have risked capital to make a hobbyist-targeted product. That would be left to an inspired optical expert to form his own company.


That’s hilarious I love it. We are CHEAP

#265 25585

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Posted 25 September 2019 - 01:40 AM

I would like to pay tribute here to TV refractors. Though not a fan of TV eyepieces, I owe my continuing love of refractors to TV, Petzvals in particular.

 

Still have my F5 Genesis, 30 years old, an almost year old 85 and a pre-owned Pronto.

But the Genesis is my favourite, whether as a cure for burn-out, or for sky spanning star hopping on its Panoramic mount. It's OE aluminised mirror diagonal gives sharp bright views still.


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