Prime Focus Method

Connecting the camera to the telescope with a suitable adaptor enables the telescope to become a long telephoto lens.

An eyepiece placed in the adaptor will project the prime image formed by the telescope objective lens onto the film with the resulting image magnified. 

The Moon and Lunar Eclipse

As the brightness of the Moon varies according to its phases, exposure time should be adjusted. During the process of a lunar eclipse, the brightness is diminishing, thus the exposure should be increased accordingly. To record the reddish-orange colour of the eclipse, the exposure should be 10,000 to 100,000 times the exposure for a normal Moon.

Since sunlight is very strong, do not attempt to take photographs of the Sun, partial or annular solar eclipse without using a professional filter. However, during a total solar eclipse, when the Sun is fully blocked by the Moon, you can photograph it with a telephoto lens or even a telescope.

Planets should be highly magnified with the eyepiece projection method before their disks or surfaces could be recorded. Focusing is critical. The vibration of the telescope caused by wind or the turbulence of the atmosphere will affect the sharpness of the image.

The recommended exposure can be obtained from "Exposure Table for Magnification Photography".

Exposure Table for Magnification Photography( enlarge )