Images from the NHK Camera
Explanation of these images
These images are the results of a project of the National Astronomical Observatory of Japan that was introduced to the public about performances of the gigantic concentrating and the tied images, which are produced by Subaru Telescope in corporation with NHK in order to see the natural color development of astronomical images. The Ultra-high-Sensitivity HDTV I.I. color camera was attached to the Cassegrain focus of Subaru Telescope, and animate images were taken and then processed as still images.
According to a memorandum between National Astronomical Observatory of Japan and Nihon-Housou-Kyoukai, the copyright of the images belongs to the National Astronomical Observatory of Japan.
The observation camera uses a color-resolved prism to divide lights in three colors, R (red), G (green) and B (blue), then, it receives optics by three CCDs, and film these images.
In order to bring along its sensitivity, the camera is equipped with an Image Intensifier (I.I.), for each of these three colors to amplify strength of light about 3000 times. Moreover, it refrigerates CCD and changes methods of the image signals readout. These devices make it possible for the camera to take a longer exposure time approximately 4 to 5 seconds. As a result of these devices, it is able to show the ultra-high sensitivity that is 360 thousand times more than a regular high sensitivity camera. In order to take wide images, the camera mounts a reducer lens, which takes in a focal length 0.23 times in the front of the camera.
For the reason of this construction, when the camera is attached to the Subaru Telescope and images are taken of celestial objects, the exposure time reaches a marginal magnitude of 21 by using a standard video rate (1/60), so that, the camera is able to get lovely colored images. On the other hand, this complex optical system has a large numbers of lenses and prisms, which makes dim images, which is caused by optical blur, disperse and diffraction. Likewise, it is very difficult to coordinate united optical axis of RGB three colors.
As reasons above, images of this filming has an inferior resolution, for example, some parts of the distorted images and chromatic aberrations shows the inferior resolution. Please understand that this system does not fulfill the function of Subaru Telescope perfectly. However, it provides a fine structure and highly colorful images which small aperture telescopes are not able to provide. These images are offered for publicity and educational uses.
For users of Subaru Images
- The press:
It is unrestricted for reporting them on newspapers, TV, or magazines.
- Publishing, Exhibitions, Internet etc..:
We welcome you to put these images to practical uses, which are followed by our policy that these images are produced for one of the astronomical publishing popularization activities. Please ask the National Astronomical Observatory of Japan for the permission. In principle, the images are free.
[Application receiver: National Astronomical Observatory of Japan Subaru Mitaka office (tel. 81-422-34-3517)]
In the event the images are used with our permission, if it is possible, please provide the product (a sample copy, paper or the print part).
- When using the images, please credit the photo and use the original images (In the event the images become a second copy light by an innovation, we request immediate cancellation for using the image, and deal with a piracy.)