Leica HC PLAN S 10x/22 (Br.) M, focusable, f=25mm Eyepiece, item #507807

[j.gardavsky]

Hello all,

this high contrast Leica eyepiece completes now the set including the Tele Vue and Zeiss Plössls at f=25mm,

Leica HC Plan M.jpg

The first impression is that of a precisely tooled full metal body, crystal clear glass inside, and a hard eyeguard,
all well fitting in my hand and to my eye, enough eye relief and nose relief, nothing too much or too less,
everything as it should be.

Technical specifications:
Focal length: f=25mm
Apparent field of view: 50°
Weight: 132.5g
Barrel diameter: 30mm, barrel length: 34.5mm
Total length: 79mm, maximum diameter: 38mm
Eyeguard inner diameter: 31.4mm, eye relief: ca 14mm
Reticule plate: optional (M), diameter 26mm
Inner focusing: very smooth helical focusing on the field stop, dioptre adjustment – 6.8 up to +4.2, the neutral internal focus position is marked with a silver ring
Coatings: Fully multicoated, each lens has its specific multicoatings (yellow, amber, pale blue, and violet taints)
This eyepiece is not purged, or otherwise protected against the fogging, restricting its use when the environments are cold and humid

Delivered:
Plastic canister, no caps, original box not available, pre-owned in excellent condition

Manufacturer’s information:
https://www.leica-microsystems.com/p...nd-graticules/
https://www.leica-microsystems.com/p...t-microscopes/
and also included in the manuals to the Leica DM6000FS microscope.

Search availability in the U.S.: https://spectraservices.com/507807.html , and others


Test with the green laser pointer:
The optics scheme is: (1- field stop -1-1-2)
The field lens is a singlet concave out, the eye lens is a cemented doublet convex out.
Two lenses inside reveal a hardly visible scatter, and they are probably made from the Leica proprietary fluoride glass materials, my guess.
The other lenses show not bright but still well visible scattered light traces, similarly to the high grade high refractive index glass materials.
The laser beam impact patterns on the glass/air surfaces show minimal diffusion, indicating high grade polish and a precise deposition of the multicoatings.

The optics scheme and the laser beam tracing makes it fairly plausible to regard this Leica HC Plan S as a continuation of the old Leitz Periplan GF legacy, see post #8 in Becoming friendly with the Leitz Periplan GF eyepieces

Terrestrial test
Date and place: 7th December 2017 early afternoon, set up on the terrace
Telescope: 6” F/5 Synta (Sky-Watcher) achromatic refractor
Test target: Houses down in the valley, about 1,000 m away
Observing conditions: 6°C, no wind, good visibility and low atmospheric turbulence
Documented with: Lumix GF7 hand held on the eyepiece, objective setting for the full field of 50°, no post-processing

This eyepiece reveals amazing sharp and contrast views with the smallest details resolved down to the Dave's limit)* , as shown in this enlarged section of the center field,

Leica HC Plan enlarged.jpg

The full field (50°) is free from distortion,

Leica HC Plan full field.jpg

The CA is under control in the center field, the lateral CA becomes visible towards the edge of the full field,
as expected due to the mismatch of a strictly planar eyepiece with a convex focal space of a fast achromatic refractor.

The views through the eyepiece, and the pictures taken with camera, reveal a cold color rendition, which may be due to the lacking UV cut (or skylight cut), and/or due to an enhanced transmissivity of light on the blue wavelengths, as required in the high resolution and fluorescence microscopy.

)* The resolution limit has been estimated on the 3.5mm cross section diameter wires in the fence in the tested scene as in the post #12 on the Leica B 20x WW and Leica B 32x WW eyepieces in Leica Eyepieces: B 20x WW, B 32x WW, and 25x - 50x WW 80° ASPH.

Disclaimer
This is not a purchasing recommendation, as different users of the astronomy equipment may prefer different choices.

Thanks for reading,

JG

[DeanD]

Thanks JG!

I like the lack of CA in the central part of the image considering that you are using an f5 achromat.

How does it compare with the Televue and Zeiss plossls that make up your "set"? Have you tried it at night yet? (It looks like there would be some coma when looking at star fields, but I guess that is more due to the fast optics of your scope.)

Your neighbours over the park need to have a "Hello JG" sign on their windows!

All the best, and keep up the good work.

Dean

[j.gardavsky]

Hello Dean,

this has been just a short test due to the weather conditions we have, so no chance to test it against the CZJ Plössl,
or against the Leitz Periplan GF.
The Leica Periplan GF 12.5x (f=20mm) might be very close in contrast and resolution, but the transmission of light might be lower, my guess.
The closest eyepiece regarding the contrast, resolution and light might be the Leica B 20x WW f=22mm, but as with the sports optics eyepieces, it has the UV (skylight) cut as required for the high color contrast in the long range viewing.
The long focus spotting eyepieces from Swarovski may be a bit behind, even if these are truly great eyepieces.
The Zeiss 23x/30x B WW f=17mm is already too short to take it for a valid comparison

From what I have seen, I would not expect coma or astigmatism on the Leica HC Plan S.

What I have been looking for, it is the ultimate contrast, a good correction, and high transmissivity, - all of them on the blue wavelengths so important for the nebulae and most of the galaxies.
The high resolution down to the Dave's limit is a nice added gift.

I have been tempted to bid for a convolute of boxed Leitz GF Periplans, but looking at the drawer,
I have found out that I already have 8 Leitz/Leica eyepieces.
What I'll eventually add in future, these might be the short focus Leica HC Plan S eyepieces, this would make sense.

Best,

JG

[DeanD]

I have been tempted to bid for a convolute of boxed Leitz GF Periplans, but looking at the drawer,
I have found out that I already have 8 Leitz/Leica eyepieces.

That really is an amazing sock drawer you have there JG!!!

I'm looking forward to the star tests.

All the best,

Dean

[Don Alvarez]

Disclaimer
This is not a purchasing recommendation, as different users of the astronomy equipment may prefer different choices.

Lol is this a thing now? I definitely have to come up with one of my own. I'll throw it to my legal department and see what they come back with.



Disclaimer
The ideas and opinions in this post represent the musings of Don Alvarez, incomitatus, and are not reflective of an expert astronomer, or a sane person for that matter, and certainly are not representative of AstronomyForum.net. His wife and kids don't listen to him, nor did the police when he said he was just kidding about the bagel incident. So you probably shouldn't listen to him either.

[j.gardavsky]

Lol is this a thing now? I definitely have to come up with one of my own. I'll throw it to my legal department and see what they come back with.
...

Hello Don, and thanks for asking.

We are sometimes using such or similar disclaimers to avoid an impression that the poster might be in whatever connection with the vendors, marketing, or other forms of support or promotion of a specific product, when reviewed in the post, and when an impression of a product support for a profit might arise.

A disclaimer does not apply to the posts generally discussing products, their properties, and ways of applications.
Thank you for your understanding,

JG

[DeanD]

The ideas and opinions in this post represent the musings of Don Alvarez, incomitatus, and are not reflective of an expert astronomer, or a sane person for that matter, and certainly are not representative of AstronomyForum.net. His wife and kids don't listen to him, nor did the police when he said he was just kidding about the bagel incident. So you probably shouldn't listen to him either. [/I][/SIZE]

I like it Don! (... although we probably already guessed most of it anyway!)

- Dean

[Eagleheaf]

The HC arrived today. Very nice object. I was not aware that this one has a set of reticles.
One center set and two on the perimeter. I will need to figure out what measure they are to put them to use on the stars.
Are you familiar with this JG?

[j.gardavsky]

Hello Mark,

congratulations on the Leica HC Plan, it is a jewel among the eyepieces!
Mine has been without reticule, you would eventually need a reticule when measuring the position angle in the double stars, or when sketching.
The reticules are pretty expensive, so keep them in the drawer, or sell them for a good money.

Now, all we need are clear skies, and your first light report through the Leica,

JG

PS: "Reticule" sounds a bit french, we also say "reticle".
In any case, I'd celebrate your new EP with a glass of good champagne, glass to glass and cheers,
you know.

[Eagleheaf]

This is how the reticle looks. I may need your help to interprit it. :-)

I will toast tonight with a snifter of 20 year old Tawny Port. :-)