40
Photography with a 35mm Camera
Photography through your ETX model requires the addition of the optional #64
T-Adapter (see OPTIONAL ACCESSORIES, page 43). With the #64 T-Adapter attached
to the telescope (
Fig. 28), through-the-telescope photography is possible with any
35mm camera body with a removable lens. In this way the telescope effectively
becomes the lens of the camera.
For through-the-telescope photography, turn the flip-mirror control (5, Fig. 28) to the
“down” position, allowing light to pass straight through the telescope and out the photo
port (
Figs. 29a and 29b). With the flip-mirror control in the “down” position and the
photo port’s dust cover removed, you can see the front lens of the telescope when you
look through the photo port. The #64 T-Adapter threads onto the photo port, followed
by a T-mount for the particular brand of 35mm camera being used, followed by the
camera body (with the camera lens removed).
The #64 T-Adapter consists of two sections (
1 and 2, Fig. 28), which are threaded
together in shipment. You may use either of the following photographic mounting
formats to couple the camera body to the telescope’s photo port thread.
• Format 1: Camera Body + T-Mount + Section (1) of the #64 T-Adapter (7, Fig. 28).
ETX-90AT 1250mm at f/13.8
ETX-105AT 1640mm at f/15.6
ETX-125AT 1900mm at f/15
Format 1 utilizes only the short section of the #64 T-Adapter to permit close-coupling
of a camera body to the telescope. In this format vignetting will occur; the
photographic image will appear on film with a slight darkening at the corners of the
35mm frame (see
Fig. 30).
• Format 2: Camera Body + T-Mount + Sections (1) and (2) of the #64 T-Adapter (see
Fig. 28).
ETX-90AT 1450mm at f/16
ETX-105AT 1830mm at f/17.4
ETX-125AT 2310mm at f/18
Format 2 utilizes both sections of the #64 T-Adapter threaded together to form a rigid
unit. In this configuration there is no field vignetting; images are illuminated to the
edges of a standard 35mm frame (see Fig.
31).
To frame an object in the viewfinder of the 35mm camera body, slightly loosen the
knurled attachment ring (3, Fig. 28), which threads the #64 T-Adapter to the
telescope’s photo port; rotate the camera body to achieve proper framing of the
object; then re-tighten the knurled ring.
PHOTOGRAPHY
Fig. 28: Example of photography through the ETX using the #64 T-Adapter: (1) Short
section of #64 T-Adapter; (2) Extension section of #64 T-Adapter; (3) Knurled attachment ring;
(4) T-mount; (5) Flip-
mirror control in “down” position; (6) 35mm camera body; (7) Format 1.
1
2
6
4
5
7
3
Fig. 29a: Flip mirror control in
the “up” position.
Fig. 29b: Flip mirror control in
the “down” position.
Fig. 30: Example of a format
1 photo.
Fig. 31: Example of a format
2 photo.