John A Roberts
Well-known member
In 2015, Omid started a thread inquiring as to how the reticle projection system on the STR telescope works
There were nearly 1,400 views but no replies! (see: https://www.birdforum.net/showthread.php?t=314386 )
So better late than never . . .
The STR consists of:
A) an objective housing using the STS/ ATS objective and focusing glass
B) with the addition of a rear module containing:
- a primary optical system using a Porro prism pair, and
- additional optics and electronics to project an illuminated reticle onto the image
The reticle is projected into the eyepiece prism (i.e. the one closest to the objective) by using an attached beam splitter
The Swarovski patent indicates that the reticle (referred to as ‘a mask’) is illuminated from behind by a battery powered light source
And the illuminated reticle can be adjusted both for brightness and focus (dioptric correction)
The STR uses the eyepieces of the ATS/ STS telescopes
- - - -
Apart from the basic information on the STR page on Swarovski’s website, the only other information that I’ve found is:
- the STR manual (20 MB in size and downloadable from the STR home page)
- two cross-section images (I downloaded these some time ago, but can no longer locate the source)
- the US patent, and
- a 2014 Fact Sheet by Swarovski
- - - -
For purposes of illustration I’ve attached copies of:
- a page from the manual showing the controls
- the two cross-section images
- an image from the patent showing more of the detail of the reticle components, and
- the specifications from the Fact Sheet
Somewhat alarmingly the Fact Sheet lists the STR’s light transmission at only 75%, compared to the 82 to 86% of the STS/ ATS telescopes (and 86% for the STX/ ATX scopes)
This is presumedly an unavoidable consequence of the addition of the reticle projection technology
Without the additional components, and when using Porro prisms, one would expect higher transmission than that of the regular STS/ ATS units using Schmidt-Pechan roof prisms
There is often a similar problem with transmission levels when manufacturers incorporate laser rangefinder technology into optics
e.g. see the varied transmission graphs for the different brands of rangefinder binoculars in this thread: https://www.birdforum.net/showthread.php?t=379668
continued . . .
There were nearly 1,400 views but no replies! (see: https://www.birdforum.net/showthread.php?t=314386 )
So better late than never . . .
The STR consists of:
A) an objective housing using the STS/ ATS objective and focusing glass
B) with the addition of a rear module containing:
- a primary optical system using a Porro prism pair, and
- additional optics and electronics to project an illuminated reticle onto the image
The reticle is projected into the eyepiece prism (i.e. the one closest to the objective) by using an attached beam splitter
The Swarovski patent indicates that the reticle (referred to as ‘a mask’) is illuminated from behind by a battery powered light source
And the illuminated reticle can be adjusted both for brightness and focus (dioptric correction)
The STR uses the eyepieces of the ATS/ STS telescopes
- - - -
Apart from the basic information on the STR page on Swarovski’s website, the only other information that I’ve found is:
- the STR manual (20 MB in size and downloadable from the STR home page)
- two cross-section images (I downloaded these some time ago, but can no longer locate the source)
- the US patent, and
- a 2014 Fact Sheet by Swarovski
- - - -
For purposes of illustration I’ve attached copies of:
- a page from the manual showing the controls
- the two cross-section images
- an image from the patent showing more of the detail of the reticle components, and
- the specifications from the Fact Sheet
Somewhat alarmingly the Fact Sheet lists the STR’s light transmission at only 75%, compared to the 82 to 86% of the STS/ ATS telescopes (and 86% for the STX/ ATX scopes)
This is presumedly an unavoidable consequence of the addition of the reticle projection technology
Without the additional components, and when using Porro prisms, one would expect higher transmission than that of the regular STS/ ATS units using Schmidt-Pechan roof prisms
There is often a similar problem with transmission levels when manufacturers incorporate laser rangefinder technology into optics
e.g. see the varied transmission graphs for the different brands of rangefinder binoculars in this thread: https://www.birdforum.net/showthread.php?t=379668
continued . . .
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