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alanjgreen

Every Dog has its Day (or does it?)

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I have started making changes to my eyepiece collection!

Having sold some fantastic "modern" eyepieces (Televue Delos) recently, the postman has delivered me a couple of "old men", the Televue 55mm Plossl & Televue Panoptic 27mm (seen pictured with the Televue Panoptic 35mm that I acquired a couple of weeks back).

NVeye.jpg.e4d06a5fd0418b6eeb352ccd35773603.jpg

These "old dudes" are about to "have their day" once again when I get up & running with "Night Vision" later in the year...

- the 55mm plossl will act as a 0.5x reducer (speeding up big dob to f1.9)

- the 35mm Panoptic will act as a 0.7x reducer (speeding up big dob to f3)

I decided to jump on a 27mm Panoptic as an alternative to "buying a Dioptrx adapter for my 24mm Panoptic" and I gain 4mm of eye relief in the process.

- Eye relief is important as you have to get the image up to the objective lens of the image intensifier tube

- I am assuming that the fast light cone of big dob will be better served with 2" eyepieces so I have stayed away from the 1.25" plossls for that reason (and the fact that a chunky 2" is easier to handle in the dark with gloves etc)

Further up the power scale, I have recently sold two fantastic Panoptic 19mm eyepieces, which I have replaced with two DeLite 18.2mm (for the 20mm eye relief that the Night Vision needs plus they accept Dioptrx which is needed for the Televue TNVC Afocal adapter to attach to).

del.thumb.jpg.59b6176aa5607e01753a300771a6d73b.jpgtnvc1.jpg.03c50268378dbb0aaa2b0be060e49355.jpg

A couple of "young guns" to keep the "old men" company!

More to follow...

Alan

Edited by alanjgreen
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Its going to be interesting to see how you get on with the Night vision. I understand Gavstar thinks NV are a real benefit in the Frac

Not a cheap accessory I understand a quality Night Vision gear. But in that Big Dob of yours it may produce some outstanding result. Good luck and let us know how you get on in this age of the NV accessory ?

 

 

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Just be aware that the 27mm Panoptic has only 14mm of measured, usable eye relief with the eyecup flipped down.  With the cup removed, you might gain one or two more millimeters.

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1 hour ago, Louis D said:

Just be aware that the 27mm Panoptic has only 14mm of measured, usable eye relief with the eyecup flipped down.  With the cup removed, you might gain one or two more millimeters.

Of course, the rubber eye cup is removed and replaced with the Televue TNVC afocal adapter which attaches directly to the Dioptrx connection and screws directly into the pvs-14 monocular.

If the eye relief does not put the image exactly at the night vision objective lens then the outer fov can be affected.

Luckily, the Panoptics have 68 degree fov and with the NV only using the centre 40 degrees, I have plenty to spare!

Having recently tested the pan27 in my Borg, I have to say it's a superbly sharp EP and I really liked it :) 

Edited by alanjgreen

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They say the 27mm Panoptic is the pick of the range and it is the only one that of what was a range of 6 that I have not had, thought the 15mm and 19mm have long gone I still use the other almost ever session even though I have many others. I liked the 55mm as well, sharp as any I have used.

Alan

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A well thought through line up... Looking forward to hearing how it goes with the night vision gear.

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I have the 55 Pl & 35 Pan for looking through, as well as a 40mm Pan. All great & have good eye relief - TV's big 2" three for that in fact. Did you intentionally choose 2 inch eps Alan?

Glad to know someone else appreciates them too :)

Edited by 25585

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16 hours ago, 25585 said:

I have the 55 Pl & 35 Pan for looking through, as well as a 40mm Pan. All great & have good eye relief - TV's big 2" three for that in fact. Did you intentionally choose 2 inch eps Alan?

Glad to know someone else appreciates them too :)

For night vision, I needed long focal length eyepieces with focal length >27mm as they produce a side effect of decreasing the focal ratio of the scope (with night vision monocular) and this produces better results when matched with the f1.2 focal ratio of the night vision monocular itself.

I will be using a paracorr2 in the dob with the eyepieces and 2" means that I don't need the 1.25" adapter.

The big dob has a fast wide light cone and I want to use 2" filters so 2" just seemed the way to go. I also like Panoptics!

At 18.2mm and below I will be using 1.25" eyepieces but I own quite a few of those to play around with already.

I had NO eyepieces longer than the 21 Ethos until I added the 3 big fellas above.

Edited by alanjgreen
Typo
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1 hour ago, alanjgreen said:

For night vision, I needed long focal length eyepieces with focal length >27mm as they produce a side effect of increasing the focal ratio of the scope (with night vision monocular)

Alan, I think there is a typo here, using long focal length eyepieces decreases rather than increases the f ratio of the scope. NV thrives on fast optical setups.

I guess one disadvantage of NV monoculars is that they are all 27mm, which means that it’s not possible to use high magnification and also keep the f ratio low (to give the best results)

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As far as I know gen 3 NV-devices are not allowed for exports out of the US. How is the legal situation concerning these Televue/TNVC devices in the UK?

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8 hours ago, marcus_z said:

As far as I know gen 3 NV-devices are not allowed for exports out of the US. How is the legal situation concerning these Televue/TNVC devices in the UK?

Fine, the televue/tnvc is just an adapter not a night vision device so no issues importing it into the UK.  

You then need to get a pvs-14 night vision monocular which are available as European made with European made tubes (eg photonis tubes). The photonis  tubes are gen2+ but the latest photonis intens gets quite close in performance to the best USA made gen 3 tubes.

However my understanding is that taking the European NV devices to the USA is not a good idea because that would be illegal under itar rules.

Edited by GavStar

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10 hours ago, marcus_z said:

As far as I know gen 3 NV-devices are not allowed for exports out of the US. How is the legal situation concerning these Televue/TNVC devices in the UK?

"Harder Digital" make gen3 devices in Germany. 

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11 hours ago, alanjgreen said:

"Harder Digital" make gen3 devices in Germany. 

nice :icon_biggrin:

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Gen 3 tubes have a wide variation in quality (like gen 2 tubes!). So it’s quite possible that a gen 2+ tube would materially outperform an older or lower quality gen 3 tube. The specs of my photonis 4g tube are up there with very good gen 3 tubes.

I haven’t managed to find any comparisons or reviews of the Harder gen 3 tubes - they seem to be much less known than the photonis tubes. It appears that Harder Digital acquired a Serbian night vision manufacturer a while ago and that’s where the gen 3 manufacturing capability comes from.

When I bought my night vision monoculars, the retailer suggested from his experience that the photonis 4g would be better in most aspects for astronomy.

But it would be nice to see directly how a Harder Digital gen 3 tube compares with the photonis 4g.....

Edited by GavStar

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