Lunt LS80 - Binoviewer Eyepiece Shootout TV Pan 19 vs TV Delite 15 vs Lunt 21-7.2 Zoom

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Lunt LS80 - Binoviewer Eyepiece Shootout TV Pan 19 vs TV Delite 15 vs Lunt 21-7.2 Zoom

Post by Tigger »

Lunt LS80 – Binoviewer eyepiece shootout TV Pan19 vs TV Delite15 vs Lunt 21-7.2 Zoom[/i]

I have recently been using my Lunt LS80 THa single stack with a Baader Giant Mk V binoviewer fitted with a 1.75x GPC.
In order to get focus with the bino, I had to remove the spacer between the etalon and the focuser unit. The focuser is then attached to the etalon using the same three grub screws. Using the 1.75 GPC, focus is around halfway along the crayford focuser without pulling the Blocking filter out at all. Its almost as if Lunt designed the scope around the MK V because its so perfect.
I use the 1800 blocking filter. There is no vignetting and the disc is beautifully and evenly lit across the whole diameter. There is no ‘sweet spot’ and it’s a joy to observe using the binos which give that natural 3D view. In addition, binos provide more contrast (must be sometime to do with using both eyes together) and I find I can observe for longer because the eyes do not get so tired.
Ok so on to the shootout. Its between the Televue Panoptic 19mm (Mag 52x) vs Televue Delite 15mm (Mag 65x) vs Lunt 21-7.2mm Zoom (Mag upto 136X). I have selected these Eps because I already successfully use the 19 & 15mm with my nighttime scopes. The Lunt Zoom because they offer increased magnification and flexibility as zooms. I was also interested to see if the Lunt coatings would increase contrast for a given similar magnification compared to a night time EP.
I have decided to rate them by Comfort, viewing Proms and viewing Surface Detail.
Lunt with Panoptics
Lunt with Panoptics
Lunt with Panoptics.jpg (908.22 KiB) Viewed 200 times
19mm Panoptic
Comfort - The most comfortable EP of the 3 to use. Its small and light and tapers away from the eyecup. A perfect shape for binos and to be able to get your nose between the Eps. The Pans are also very forgiving about eye placement without kidney beaning. Score 3 points

Viewing Proms – The Pans give a fantastically bright view. The proms really are very bright and almost have their own fire. Faint proms are easy to see. BUT the pans are only x52 mag, which means that the image does not fill the whole view and there is quite a big gap of blackness from the edge of the sun to the edge of the EP. The image is too small for my tastes. Score 3 points

Viewing Surface Detail – The Pans are again very sharp but they are also very bright and do not offer a decent amount of contrast, probably because the image is too small. Don’t get me wrong, it’s a wonderfully sharp view, just when they are up against the others in this shoot out, they don’t quite cut the mustard. Score 1 point.

15mm Delite
Comfort – These are big EPs for a binoviewer. The eyecup does not taper at all and the diameter is quite large. This is then compounded if the rubber eyecups are raised. That said, I have now found the best compromise. I set the eye relief at its lowest setting and roll up the rubber eyecups. The position is no where near as comfortable as the Pans, but usable. Score 1 point.

Viewing Proms – The reason for compromising with the comfort is the view of the Proms. The sharpness and level of detail that can be seen with the Delites is jaw dropping. A ‘normal’ prom is transformed into a complicated beautiful object in its own right. Individual blobs of plasma can easily be seen along with the complex structure.
Faint proms seem to have their own internal illumination and detail can be seen easily. With reasonable seeing, the spicules at the edge of the sun can easily be seen in lovely detail. I use these to gauge the seeing. The best EP here for viewing proms. Score 5 points

Viewing Surface Detail – The Delites are wonderfully sharp so it is very easy to see sunspots, plage filaments and the lines of magnetic flux around the sunspots and filaments. The contrast is very good and the ‘orange peel’ is easy to see. Solar flares stand out as bright lights against the contrasty background. I thought the surface detail could not be beaten, but read on. Score 4 points.

Lunt 21-7.2 Zoom
Comfort – The Lunt is neither as comfortable as the Pans or as uncomfortable as the Delites. Its in the middle of the two. There are no roll up eyecups. Instead you get a hard rubber adjustable cup that you can adjust the eye relief by twisting up and down. I fine the best position is the lowest setting. Comfort is Ok, score 2 points

Viewing Proms – Because the lunt is a zoom, I was able to set its magnification to be the same as both the Pans (19mm) and Delites (15mm) to do a direct comparison of lens quality and sharpness. It will come as no surprise that the Lunt was not as sharp as either the Pans or the Dels. It was not far behind either of them, but if you are looking for absolute sharpness then fixed length EPs are always going to win out. The Lunt, however, can play its trump card by increasing magnification. I found that between 13.5-10mm was the best compromise between mag and resolution on the proms, but I preferred the Delites at 15mm. Proms were very good, score 3 points

Viewing surface Detail – This is where the Lunt really came into its own. Again I did the direct mag comparison with the other two shooters. The Lunt consistently showed more contrast and it was easier to see more detail. The real joy of this EP was when I cranked up the mag to 10mm (98x) or with good seeing, 7.2mm (136x). The contrast increasing dramatically and a sunspot or filament becomes a object of beauty with lovely detail. I think Lunt must put a coating on their eyepiece to enhance the solar view. I am asking myself the question of whether I need a double stack because the Binos coupled with the high mag zoom give a really constrasty view without the hassle of setting the PT on the second stack and the red glow associated with the internal DS. Surface detail is awesome, score 5

There is no such thing as the perfect eyepiece. I use the 15mm Delites for the Proms and the Lunt Zoom for the Surface because of the contrast at high mags. If I had to choose just one pair? That’s a really difficult question to answer. I think it would be the Lunt Zoom because its so versatile and the high mag surface views are intoxicating, but the sharpness of the Delites is awesome.

Clear skies to you all.
Lunt with Zooms.jpg
Lunt with Zooms.jpg (686.19 KiB) Viewed 200 times
Lunt with delites.jpg
Lunt with delites.jpg (1.15 MiB) Viewed 200 times

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Re: Lunt LS80 - Binoviewer Eyepiece Shootout TV Pan 19 vs TV Delite 15 vs Lunt 21-7.2 Zoom

Post by marktownley »

Thanks for the review! :)

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Re: Lunt LS80 - Binoviewer Eyepiece Shootout TV Pan 19 vs TV Delite 15 vs Lunt 21-7.2 Zoom

Post by RKBerta »

Interesting results. I have a 60mm Coronado external etalon (the original US made version) with the 30mm BF and used with a Astro Physics 2" diagonal. That setup is used on either a TV 85 APO or an Officina Stellare 80mm triplet APO. I also have a Lunt 60mm pressure tuned scope with their small BF diagonal. I do have a binoviewer but I only have one set of eyepieces for it that are matched (20mm Burgess).

I did do extensive testing on various eyepieces I have but in particular the Lunt 7.2-21 zoom and the Pentax 8-24mm zoom and the latest BAADER 8-24 zoom V III. All seemed to be better choices than the fixed eyepieces...mainly because you could tweak the view by adjusting the magnification. This goes against common thinking that a fixed EP would always be better. I do have a full set of the Coronado fixed fl eyepieces and their barlow (when still US owned). I also have a full set of Pentax EPs. While all of the zooms seemed to work very well for Ha, the PENTAX zoom always gave better and more detailed views of both prominences and surface chromosphere sharp and contrasty detail. I have several friends with various Ha scopes up to 100mm aperture and in AB testing on their own scopes with my eyepieces they all came up with the same opinion. I am not sure why this would be....maybe more beneficial coatings for solar on the Pentax. This was a strange result as you would think some of these solar specific eyepieces and others with very simple optical designs would have the edge both in detail and contrast.
Between the BAADER and Lunt was close for solar although the BAADER was better for DSO and planetary which made sense since the Lunt was designed as a solar EP.

Have any of you had a chance to try a Pentax 8-24 zoom on your Ha solar scopes? Note...Pentax also has another zoom EP but I didn't find it in the same performance level as the 8-24...both for solar as well as deep sky and planetary.

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