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Swarovski ATX-115: Star-test and Resolution Measurements (2 Viewers)

Tringa45

Well-known member
Europe
With a ridiculous magnification of 360x (max zoom, XTS 1,7 + Zeiss 3x12 mono), with my ATX95
Kimmo,

You must have the dexterity of a neurosurgeon to be able to focus the ATX at 360x :).
What tripod and head were you using and how did you secure the 3x12 Zeiss to the ATX eyepiece?

John

PS:- Fine focus with the Zeiss Mono perhaps?
 

Binastro

Well-known member
Hi John,

I had no trouble testing the Pentax 100mm scope at 400x with a 3mm Clave eyepiece.

Or the 12.5 inch Dall Kirkham at 1100x with a 4mm orthoscopic eyepiece.

But both had proper astro mounts.

More difficult was the Vivitar 600mm f/8 solid Cat at 180x with a 3x teleconverter and a monocular converter.
It easily split Epsilon Lyrae both doubles with clear space between.
This was on a Slik 88 photo tripod.
I could actually observe planets with this set up so long as I didn't touch anything and if it wasn't windy.

Regards,
B.
 

Tringa45

Well-known member
Europe
Hi David,

Those were astro scopes with a Crayford or rack & pinion focusser and the depth of focus on an f/12 scope helps too. It gets difficult though on a spotter with helical focusser.

Regards,
John
 

Binastro

Well-known member
The Crayford invented by John Wall I think of Crayford astro Society maybe was later than my Dall Kirkham.
The Dall Kirkham had a focusing main mirror as per Maksutov Cassegrain plus maybe a rack and pinion. I can't remember.
Focal length 4650mm with some variation if a diagonal used or for photography.

The Pentax had a rack and pinion.
Not sure I have had a Crayford.

I used a micro drive on the Slik 88 that had fine drives by hand up and down and sideways.
However, if a planet is south then one only needs sideways movement.
I would move just out of field and let the planet drift over the field.
The microdrive fits between the head and the tripod.

However, my 120mm refractors have no focus mechanism at all.
The drawtube just slides.
I got very good at twisting drawtubes while slightly moving the tube axially.
My normal magnification was 250x.

The same applies to my 123mm refractor and drawtube terrestrial scopes. I just slide while twisting.
No, not a dance.

I am not sure if there are 115mm ATXs with no SA.

With lenses such as the Dallmeyer 36 inch f/6.3 there is enormous SA at full aperture, which becomes o.k. at f/8.7 or smaller stops.
People used to make telescopes out of these ex gov lenses, but they made very poor telescopes.
There were many available cheaply.

Regards,
B.
 
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henry link

Well-known member
...and how did you secure the 3x12 Zeiss to the ATX eyepiece?

John
I can answer that part, John. My 3x12 Zeiss monocular came with an adapter for Zeiss FL binocular eyecups which also fits the ATX eyecup. If I had bought the scope my intention was to attach the 3x12 just when I needed more than 70x. Probably not optically quite as good as the 1.7x Extender, but good enough to show the scope's resolution limit and much quicker and easier to put on and take off.

Henry
 
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Tringa45

Well-known member
Europe
Hi Henry,

Yes I also have an adapter for my 3x12 Zeiss Mono, which I was told was the largest available. It is 35,7 mm in diameter but I nevertheless had to pad it out with several layers of tape for a secure fit in the 30x W Swarovski eyecup and with even more tape for the 25-60x Kowa TE-!!WZ.
I assumed the ATX eyecups were even bigger and hand-holding is a poor option behind tripod-mounted binoculars, let alone a scope.

I don't consider myself a hobby astronomer but have played with various astronomical eyepieces on my birding scopes. Paradoxically the best view I ever had of Jupiter was with the 3x12 Zeiss behind the 30x W on my ATM65 HD for 90x - with all that glass! I guess the seeing on that night must have been exceptional.

John
 

DRodrigues

Well-known member
...
I have done some artificial star assessments on the X115's this year, but not at great length and not with a particularly excellent sample yet.
...
Kimmo,
Any of the X115 you tested bested your cherry X95 in terms of resolution?
I will have one X115 since I expect to gain resolution with the extender but your post made me to think if that would be true...
The gain in light availability with the X115 is good (I do many hours of resighting at dusk and also digiscopy...), but not my main goal.
 

henry link

Well-known member
Briefly, because the refractive index of a block of prism glass is higher than the same thickness of air it causes spherical overcorrection and increased longitudinal CA when placed in the light cone behind an objective lens. When combined with a spherically undercorrected objective lens the result can be lower spherical aberration for the prism and lens in combination than for the lens alone. Virtually all binocular objectives lenses are designed to work with prisms to lower spherical aberration.

I've observed this at work in one of my scopes with an undercorrected F/5.6 Fluorite doublet objective. Using a prism diagonal instead of a mirror almost perfectly compensates for the undercorrection of the lens.
 
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Tringa45

Well-known member
Europe
I recall seeing on Cloudy Nights that someone had built a binocular telescope with two 95 mm Swarovski modules and Matsumoto erecting mirrors.
Without the glass path through prisms I suspect that the results, at least at higher magnifications, would have been mediocre.

John
 

henry link

Well-known member
John,

I think one of the objective modules used to make that binocular is the very same one that was tested in the link in post #12.

Henry
 

Binastro

Well-known member
The ATX 115 should have a focal ratio longer than the ATX 95.
In fact it is shorter, so this makes it harder to produce an equivalent performance.

It may be that some hand figuring, or aspherising is needed to produce high quality images with the 115 ATX..
Swarovski may only have one or two in house master opticians able to do this work, if indeed this is what is needed.

If the sample ATX 115 tested was in the Covid period, the master opticians may not have been available or had their work disrupted.

This is only conjecture on my part.

Canon published a video of their master optician skilled at figuring large optics. He was not young and had been with Canon 30 years.

Sony are proud of their machine aspherics supposedly working to 1/40 wave on their large optics.

I don't think that high quality spotting scopes are difficult to make.
But high quality large aperture short spotting scopes may in fact be difficult to produce reliably to high standards.

Regards,
B.
 

Tringa45

Well-known member
Europe
I think one of the objective modules used to make that binocular is the very same one that was tested in the link in post #12.
Yes, Henry that must be it. I can't claim to understand all the test results but at least the tester remarked that the objective would profit from an additional 40 mm glass path.

John
 

jring

Well-known member
How is the non-technical unwary consumer to protect him/her self?
Hi,

learn to star test your optics. If in doubt, at least learn how to make usable images (2-3 rings offset with at least ok seeing) and post them here...

Joachim
 

kabsetz

Well-known member
Kimmo,

You must have the dexterity of a neurosurgeon to be able to focus the ATX at 360x :).
What tripod and head were you using and how did you secure the 3x12 Zeiss to the ATX eyepiece?

John

PS:- Fine focus with the Zeiss Mono perhaps?
Hi John,

I use a Velbon Carmagne 830 tripod and a Sirui VH 10 head. They provided a sturdy enough support unless there is a fair amount of wind. Unlike Henry, I don't have the Zeiss adapter for the 3x12. Instead, there's a bit of bicycle inner tube stretched over the Zeiss mono, giving it a nice and snug fit in the ATX eyecup. My ATX prism unit also has smoother than average focus action. And it is also possible to use the monocular focussing for fine-tuning the focus, although I usually don't do this.

- Kimmo
 

kabsetz

Well-known member
Kimmo,
Any of the X115 you tested bested your cherry X95 in terms of resolution?
I will have one X115 since I expect to gain resolution with the extender but your post made me to think if that would be true...
The gain in light availability with the X115 is good (I do many hours of resighting at dusk and also digiscopy...), but not my main goal.

David,

In fact, at least three of them bested my X95 in being able to show better line-pair separation, but they did not do it by as much as they should have. I'm pretty sure that for your use, which is more practical and scientific and not as heavily aesthetic as mine, the X115 (at least a good sample) will be an improvement.

- Kimmo
 

kabsetz

Well-known member
I can answer that part, John. My 3x12 Zeiss monocular came with an adapter for Zeiss FL binocular eyecups which also fits the ATX eyecup. If I had bought the scope my intention was to attach the 3x12 just when I needed more than 70x. Probably not optically quite as good as the 1.7x Extender, but good enough to show the scope's resolution limit and much quicker and easier to put on and take off.

Henry
Henry,

The 1.7x Extender (in the range it gives) gives much better views than the scope + Zeiss 3x12. Not necessarily resolution-wise, but the light loss and contrast loss that come with the Zeiss are very obvious, whereas the Swaro extender makes a barely perceptible difference, if even. Also, the viewing comfort is so much better (the same as without the extender), and FoV superior. Putting it on and taking it off is admittedly somewhat clumsier, but once you practice it a bit, not that bad.

And yes, I will keep you posted about possible cherry X115's and what they are capable of.

- Kimmo
 

Mickr

Well-known member
I have this scope and my early opinion is that it is superb, especially when used in low light. I used it a couple of nights ago, well after dusk and it looked like I was out in daylight. A few people looked through the scope and they couldn't believe how much of a difference it made. I was also using the extender and the image was reasonable but was spoiled by moisture in the air. I have the smart phone adapter which is over priced and I have the camera adapter for my DSLR which I think is either rubbish or I am thick and don't know how to set it up correctly.

 

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