Shining letters float in front of the background of the Nobeyama 45-m Radio Telescope listening to radio waves from space under the night sky. “NRO” stands for Nobeyama Radio Observatory. By moving a light during the time that the camera’s shutter is open, the light trail can be captured in a single photograph. This photographic technique is known as “light painting.” This picture was taken with a 30 second exposure. There is very little diurnal motion in this short period of time, so the stars appear as fixed points, but the drifting clouds are seen like veils.

Light Accumulation Photography Techniques and Astronomy

Since antiquity, humans have observed the Universe with their eyes. Even after telescopes were developed, observers looked through them by eye and recorded their observational results as sketches.

The human eye, which responds to the light from twinkling objects being absorbed in the retina each instant, can’t discern the shape of faint celestial objects well. Astronomy changed greatly with the advent of photography in the 19th century. By controlling the exposure time, it became possible to accumulate light from objects which can’t be perceived by the unaided eye, such as dim stars, pale-expansive nebulae, and the structure of galaxies. Today, CCDs and other high sensitivity instruments have succeeded the human pupil for capturing the light from the Universe.

The Night Sky Shifting from Autumn to Winter

This picture shows stars rising from the north-east behind the Nobeyama 45-m Telescope. The bright stars gathered together in the upper right are in the constellation Perseus, one of the typical autumn constellations. The remarkably bright star right next to the telescope is the first magnitude star Capella in the constellation Auriga. This picture shows the changing of the night-sky-hero as autumn shifts to winter.

Author: Seiichiro Naito (Public Relations Center)