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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Eyepiece for low power and low cost (1 Viewer)

Fernando np

Well-known member
Hi,
In my first scope, an indestructible Adlerscope 80, I got excellent views with the 15X fixed eyepiece at night specially with mammals, mainly foxes and wolves. Of course there was more eyepieces. Now with a Dyascope 85 I wander about the choice to spread their range at low power, one time light catering is among its stronger points. In this forum, sometimes I've been surprised cause of the good reviews for cheap eyepieces written for people with obviosly knows well what they arey are telling about. The minimum level of performance MUST implicate some improvement over the Vario zoom at 20X. Whithout budget limits the choice would be a 28mm 2" of hight quality and price. In high power I'm very satisfacied with an TV Radian 5mm 1 1/4", but that kind of prices isn't considered for low power. So, if somebody has positive experience in the 15 to 20 range please make it public. I don't expect too much answers.
 
Fernando,

No direct experience with long focal length eyepieces I'm afraid but there is no way you are going to achieve focus with a 2" astro eyepiece. The Zeiss astro adapter (1 1/4"), which fits inside the bayonet mount has an external diameter of 41mm, i.e. < 2".

There are however many 1 1/4" eyepieces around 25mm although I suspect that some of these with longer 1 1/4" barrels would not reach focus at infinity.

I have used an 11mm Televue Plössl on my Diascope 65 with the Zeiss astro adapter (the Baader Planetarium bayonet adapter is an alternative) with no problems except the 8mm eye relief.

The 25mm Plössl has 17mm eye relief, would give you 20x magnification and excellent optical quality at low cost but only 50° AFOV, about the same as the Zeiss Vario at 20x.

I expect the 24mm Televue Panoptic with 68° AFOV (short barrel) would also focus to infinity but am not sure if it is suitable for terrestrial applications (lots of pincussion?).
Perhaps one of the astronomers could help out here?

John
 
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Hi,
Zeiss has both adaptors, for 1 1/4 and 2" eyepieces, in its catalogue. So , at least some 2" must be taken in mind. The Baader system, what I regret not have bought, looks more practical when you're in the field.
In every case, I'm not in a hurry and whithout the expectation to get bigger performance than the zoom at 20X I keep on looking for alternatives. By the way, the zoom has better sealing for the scope. Here, nights are usually very clear and takes sense to have a look. Twenty years ago I spend, between work an dinner, uncountable hours looking at the fox pups in their den gates in spring. Under 100 meters, their vision for static objects is fairly poor, the 15X gave me a lot of enjoyment. Its advantage over the zoom at 20X was more than evident.

Fernando
 
Zeiss has both adaptors, for 1 1/4 and 2" eyepieces, in its catalogue.

There are two types of adapters: one to use 1 1/4" astronomical eyepieces on Zeiss Diascopes (2" astronomical eyepieces are a no-go) and the others to adapt Zeiss Diascope eyepieces to 1 1/4" or 2" for use on astronomical telescopes.

John
 
I suposse you have no problems with the full range of focusing. Would the same be said about the TV plossl 32mm?. I'm looking prizes for both, eyepiece and Baader adapter.
 
Fernando,

The 1 1/4" TV Plössls would be parfocal so no problems there.
However, the Zeiss adapter ring, which screws onto the male thread of the Diascope body fits over the body of my 11mm Plössl. It would not fit over the larger diameter body of the 32mm Plössl, which would necessitate moving the eyepiece out by 4mm (probably similar to using the Baader adapter).
Using the 11mm Plössl I have a lot more focus overtravel to infinity (and somewhat poorer close focus) than with the Zeiss eyepiece so I don't think you should have any problems reaching focus at infinity.

John
 
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Thanks, I had forgotten the parfocality matter. The TV32mm plus the Baader adapter are already for to teleskop-service.de. 157 euros, shipping included, is the best prize I've found in the european sellers. In this range of prize is a nuisance to pay the VAT apart.

Fernando
 
The TV32mm plus the Baader adapter are already for to teleskop-service.de. 157 euros, shipping included, is the best prize I've found in the european sellers. Fernando

I dealt with Teleskop Service once and was quite satisfied.
Just to make sure you would have no focussing problems, I pointed my Diascope at a distant object and set the focus to the end of travel (infinity).
With corrected vision (glasses) and the Zeiss adapter ring on the 11mm TV Plössl I was able to slide this out of the bayonet mount until I reached focus.
It required a full 10mm of outfocus so even if you are very short sighted and view without glasses you would have no problems.
No doubt you have done all the sums but with 16x magnification and a 5,3mm exit pupil the 32mm Plössl should give excellent twighlight performance.
If you decide to go ahead it would be very interesting to hear how it works.

John
 
I've just been adviced from the people of teleskop-service about how to maximize the focusing range, full range plus closest focusing distance.
In this way, taken backward 4mm the TVRadian 5mm infinite focusing keeps on and the shortest focusing is almost halved.
Next first tests will be posted here.
 
I expect the 24mm Televue Panoptic with 68° AFOV (short barrel) would also focus to infinity but am not sure if it is suitable for terrestrial applications (lots of pincussion?).
Perhaps one of the astronomers could help out here?

I use both the TV 24mm Panoptic and the 13mm Nagler with the Zeiss adapters, and both are fantastic in my 85mm Diascope. They do exhibit edge curvature (the Nagler more than the Panoptic), but its more acceptable than the edge softness of the Zeiss zoom.

I love the 24mm Panoptic in the Zeiss, and use it a lot. Awesome low-power views!

The only drawback to it is that changing it if you need a higher power EP is a chore.
 
I love the 24mm Panoptic in the Zeiss, and use it a lot. Awesome low-power views!
The only drawback to it is that changing it if you need a higher power EP is a chore.

Yes, I know the Zeiss adapter is a bit of a fiddle, although well made. The Baader Planetarium adapter, though should be quite quick and costs about the same, around €30.

If that Panoptic has a fairly flat field and not too much pincussion distortion the views at 21x mag with a 4mm exit pupil and 68° AFOV must be truly great.

Fernando, it would be interesting to read of your experiences with the 32mm Plössl.

John
 
Hi John,
I've just read your private message and decided answering here. At the same cost, it would be useful for somebody more.
First, the Baader adapter is easier for exchanging. Probably it keep on with the same ocular. It fix to the eyepiece strongely with tree allen screws. I prefer this design to the Zeiss. This kind of low-tech stuff, next to suitable caps and so, probably would be made a ridiculous cost under a generic brand.
The first impression about optical quality, well overwhelming isn't the right adjetive. Radian rates, as its price, fairly over. There must be supossed Naglers and Panoptics are even better. The stars appears as shorts // although absolutely unidimensional. The view of the Moon is more relaxed and with more detail compared with the zoom at 20X. Let's go to the animated beings, 16X is far of an overkill for birding. But large mammals, my original aim is a different matter. The first sunset and night in a wetland picked mixed outcomes. The glows on the water surface looks more problematic for the Plossl than for the zoom, even with the light gathering on the side of the 32mm. Probably somebody stronger than me in optics can explain it. With a good bunch of stars in the sky I found with the binoculars a herd of sheeps round 500 meters far. The Diascope at 20X gave me more detail. Then I change to the Plossl. Believe me, colours appeared where there weren't. It was possible to identify the sheperd, a person I know. There was no doubt about its clothes' colours and about a new dog, among their older ones, cause of the pattern of patches of his coat. Returning to the zoom the dark overflowed the fields. This experience is enough for me. Its performance in such conditions had been shown. Unluckily, there aren't thrilling night views in my planning now. I'm thinking in things such as a wolves and so.
I hope you had found some useful.
 
Fernando,

Many thanks for the interesting report. It seems that for your requirements the Plössl was a worthwhile investment.

Regards,

John
 
Less than two hours ago I've been watching a family group of four badgers starting their work night. You can be sure there's no doubt about the money spended in the Plossl.

Fernando
 
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