The analog Schlierenscope is an analog projection focusing schlieren system designed for large area applications. The apparatus is factory-aligned and comes with its own illumination system. Unlike traditional schlieren systems, the entire apparatus is contained in a single unit, so it is essentially a point-and-shoot schlieren system. This makes it massively easier to use than traditional schlieren systems, and because it is a focusing schlieren system, the system sensitivity is concentrated on a particular image plane, which can allow schlieren effects in different parts of the optical path to be distinguished.

Compared to our digital schlieren systems, it is somewhat larger, heavier, and more expensive, but it can also be more sensitive. Schlierenscopes are presently a custom order but can be fairly readily designed for ranges from 5 to 20 feet with throw ratios of around 6:1 (distance:height). Schlierenscopes have been delivered using flash illumination and can be customized for various high speed applications such as ballistics and high-speed wind tunnels (note that export outside the United States may be subject to restrictions for hypersonic wind tunnel applications).

Analog projection focusing schlieren system
Analog schlierenscope

Please see also our 2014 NASA Tech Briefs Article, "A Portable, Projection Focusing Schlieren System". The latest brochure can be downloaded at this link. Application of a high-speed system was also described in a 2014 conference paper coauthored with NASA, "Application of a Novel Projection Focusing Schlieren System in NASA Test Facilities".

Below, we show a few images captured with Schlierenscope systems.


Schlieren image of supersonic projectile and shockwaves interacting with a surface
Supersonic projectile and shockwaves interacting with a surface
Schlieren image of heated air from a lamp and a kettle
Convection from a lamp and a kettle