X115 vs. X95 (1 Viewer)

[DRodrigues]

Still is no thread dedicated to this comparison. Since several months I wanted to summarize my findings and managed to do a short version of it at CR-telescopes
The short summary is: - if money and weight aren't limitations for you, get a X115! If you already have a X95, don't want to spend money and/or don't want to carry more weight, you aren't loosing much by not updating to the X115. With the BTX, the benefits of the X115 might be higher.

 

[MustangHX]

Do we have enough samples to tell which one has better quality control? Larger glass could potentially introduce more errors during grinding and assembly. I have an impression that the Kowa 99a seems to have more lemons than 88a or 883 from the discussion here.

 

[The BulbMogul]

Still is no thread dedicated to this comparison. Since several months I wanted to summarize my findings and managed to do a short version of it at CR-telescopes
The short summary is: - if money and weight aren't limitations for you, get a X115! If you already have a X95, don't want to spend money and/or don't want to carry more weight, you aren't loosing much by not updating to the X115. With the BTX, the benefits of the X115 might be higher.

I own both and quite happy with them.

 

[Rich5555]

These scopes are a bit of a mystery. The 115mm, given the taper and length of the body, it's impossible to utilize full illumination from the front lens group. One thread mentioned two measurements for the focal length of the front elements, 431mm and 551mm. At 551mm, the light cone would have to be outside the body of the instrument not to experience vignetting/light cone edge cut-off. If it's 431mm, it matches the module dimensions. If it's the latter, the light cone is vignetted and the true aperture is less than stated. So, the 115mm may be no brighter than the 95mm at a given magnification. Only way to avoid vignetting IF the front lens group is 550mm, is if there is some kind of compression lens somewhat further behind the front elements in the objective module that diverges the light cone.

 

[Tot]

I own both and quite happy with them.

Hi wich do you find the sharpest 115 or 95 thanks

 

[Tringa45]

These scopes are a bit of a mystery. The 115mm, given the taper and length of the body, it's impossible to utilize full illumination from the front lens group. One thread mentioned two measurements for the focal length of the front elements, 431mm and 551mm. At 551mm, the light cone would have to be outside the body of the instrument not to experience vignetting/light cone edge cut-off. If it's 431mm, it matches the module dimensions. If it's the latter, the light cone is vignetted and the true aperture is less than stated. So, the 115mm may be no brighter than the 95mm at a given magnification. Only way to avoid vignetting IF the front lens group is 550mm, is if there is some kind of compression lens somewhat further behind the front elements in the objective module that diverges the light cone.

According to this link, https://www.cloudynights.com/topic/729314-swarovski-atx-95-optical-test/, the 95 objective module is f/5,8, which corresponds to a focal length of 551 mm. As the magnification range of 30-70x is the same with the 115 mm objective, the focal length would be similar giving an extremely "fast" focal ratio of f/4,8. Not really surprising that its optical properties leave something to be desured.
Most waterproof spotting scopes use internal focussing and many recent designs use a negative focussing lens resulting in a similar construction to a telephoto lens. This has the added benefit of reducing the overall length.

John

 

[DRodrigues]

According to this link, https://www.cloudynights.com/topic/729314-swarovski-atx-95-optical-test/, the 95 objective module is f/5,8, which corresponds to a focal length of 551 mm. As the magnification range of 30-70x is the same with the 115 mm objective, the focal length would be similar giving an extremely "fast" focal ratio of f/4,8. Not really surprising that its optical properties leave something to be desured.
Most waterproof spotting scopes use internal focussing and many recent designs use a negative focussing lens resulting in a similar construction to a telephoto lens. This has the added benefit of reducing the overall length.

John

The erecting prisms also reduce the length of the spotting scopes, when compared to astro-refractors.
The X115 has about 1% longer focal length than the X95, as mentioned at my page linked above. That is more noticeable when using the 1.7x extender.

 

[DRodrigues]

... The 115mm, given the taper and length of the body, it's impossible to utilize full illumination from the front lens group. ...

The STX115 and the ATX115 use all aperture. Ironically, the BTX115 doesn't...
At Swaro X derivations you can see how to get much wider FOVs from a X objective module.