A gas-lens telescope

Lensing properties of rotational gas flow

“…Positive (focusing) gas lenses were demonstrated in long, heated, spinning tubes [3]. These lenses were used for imaging distant objects [4] and proposed for applications in astronomy. Focusing of laser beams for metal cutting applications was also successfully demonstrated in heated tube lenses [5].…”

Aero - Optics: Controlling Light with Air

“…Another improvement was to combine both rotation and gas injection to create a steady focus (Notcutt, 1988). An interesting application was when the SPGL was used as a high quality telescope objective to take images of sun spots and moon craters, illustrating the power of such devices (Michaelis, 1991). Further improvements included operating the SPGL at pressures higher and lower than atmospheric pressure (Forbes, 1997) in order to control the focal length, and careful characterisation of the temperature distribution inside the pipe (Lisi, 1994).…”

Non-solid non-rigid optics for high-power laser systems

“…We employed a SPGL to demonstrate the quality of gas lenses by imaging a water tower at a distance of 5 km, sunspots and various phases of the Moon: fig. 4 (20). The SPGL was one meter long, had an internal diameter of 25 mm, was apertured down to about 8 mm and heated to a temperature of about 70 o C. 21) is a versatile pulsed gas lens that as its name implies, results from the collision between a number of shock waves generated by discharges in air.…”