INSTRUMENTS
 

ASTRAL TELESCOPE

page 12

PHOTOGRAPHIC USE

With the appropriate adaptors it is possible to use a telescope as an objective for the common reflex-type camera. In order to do this you will need:
1) a reflex camera with an interchangeable objective, with an automatic release.
2) A photography adaptor (to be chosen from among those available with every model.)
3) a T/2 ring which varies depending on the make of camera.

Different methods of taking photographs exist (described in the manual GENERAL NOTES) and each type of photography is chosen according to the result you want to obtain. For example, for photography of terrestrial objects direct focus photography is recommended whereas to photograph the Moon, you can achieve satisfactory results with the ocular projection method. Consult the list of optional accessories for your telescope to know which adaptors are available for the type of photography that interests you.
For mounting the various accessories do as follows:
DIRECT FOCUS PHOTOGRAPHY (fig. 12) for adaptors :
a) remove the objective 0 from the camera following the instructions for use accompanying the camera.
b) take the photography adaptor 0, and screw in the T/2 ring.
c) Put the T/2 ring and the photography adaptor on the body of the camera.
d) Insert ail in the focusing tube 0 of the telescope in place of the oculars.
N.B. Adaptors 1069 and 1070 can be used for two types of photography; for direct focus photography it is necessary to make two parts of the adaptor as shown in the instructions.

OCULAR PROJECTION PHOTOGRAPHY (fig 13) :
a) remove the objective (C) from the body of the camera as shown in the instructions manual.
b) Take the photography adaptor (A) and screw in the T/2 ring (B).
c) Insert the ocular that you want to use in the inside of the adaptor (E) and fix it in place in the central part with the appropriate screws.
d) Put ail in place along with the T/2 ring in the body of the camera.
e) Place all in the focusing tube (D) of the telescope in place of the oculars.

A - photo adaptor
B - T2 ring
C - body ofthe camera
D - telescope tube
E - ocular support
F - fixing ocular screws

PARALLEL PHOTOGRAPHY.
This adaptor is fixed to the counterbalancing rod of the equatorial mounting (which has to be motorized for the Right Ascension). This operation has to be carried out before assembling the counterbalancing rod on the mounting. On the adaptor you will see a screw with a photography-style thread, on which you will have to fix the camera with its "normal" objective.
Once you have completed the balancing operation and the equatorial positioning described on page 70, point the camera towards the celestial zone that you wish to photograph, start the motor and take the photograph. Taking advantage of the "B"-type pose, you will be able to get exposures of one or two hours that will allow you to get on film a great deal more detail than that you can see with the naked eye. Obviously, for a good photograph you will need to ensure that the mounting has been accurately carried out and positioned according to the Polar Star. You will be able to note any errors in tracking by using the telescope as a guide telescope. Keep a reference star at the center of your field of vision (not necessarily the star that you are photographing) and you will notice that with the passing of time, the star will tend to move from the center of the field, allowing you to make the necessary corrections.