Omegon 49751 User manual

Reproduction of part or all of the contents of this document in any form is expressly prohibited other than for individual use only. All text, images and labels are property of nimax Gmbh.

Instruction Manual

Congratulations on the purchase of Omegon® variable

projection and focal adapter 1.25”. Also known as tele-

extender, it is used for afocal photography with an

eyepiece and a camera.

1. How does it work? A 1.25”eyepiece –with a

maximum of body diameter of 38m - is inserted

(eyepiece lens facing out) in the system through the

aperture on the back (#5 –figure 1). Then it slides all the

way in so that it is fixed by the Eyepiece fixation

thumbscrew (#6 –figure 1). Usually one wants to start

using an eyepiece of high focal length (say 25mm). The

camera can be attached to the T-Threads (#5 –figure 1)

if it has T-Threads (M42x0.75).

In theory, any camera with T-Threads or with a T-ring

can be used for projection photography. The

performance depends on the combination of distance

between the eyepiece and camera sensor, eyepiece

optical design and camera sensor (size).

2.1. Attaching the tele-extender to the telescope. The

assembled system (as decribed in 1) should now be

attached to a telescope. There are two options. If the

telescope’s focuser has T-Threads we suggest removing

the 1.25”nosepiece from the telextender and directly

attach it to the telescope. It provides more stability. If

the telescope focuser, on the other hand, only accepts

1.25”eyepiece barrels use the supplied 1.25”nosepiece.

2.2. Focusing. Before using the tele-extender make sure

to first focus the eyepiece. This gives you a rough focus

oint when using the tele-extender.

2.3. Focusing with the camera. Release the two

Extender fixing rings (#3 –figure 1). So that the T-

threads body (#4 –figure 1) slides freely in and out. Slide

all the way in so that the camera is at its closest position

to the eyepiece. Now start by racking in (or out) the

focuser to get a sharp image (focused) as seen by the

camera screen. The light from the eyepiece is being

projected to the camera. Depending on the camera’s

sensor distance to the eyepiece so is magnification

different.

3.1. Magnification and how it works. Using a long focal

length eyepiece provides less magnification than using a

short one. The longest the distance between the camera

and the eyepiece the biggest the magnification.

3.2. Illuminated Field. Camera sensors vary in size.

Photography using eyepiece projection usual deliver an

illuminated circle with the image and the surrounding

image is rendered black. This effect is technically

impossible to solve. The performance however is very

good for planets and the Moon. Therefor we

recommend testing several setups with different

eyepieces and distances to find the best setup.

DSLR Cameras usually use bayonet systems that

allow to change objectives. Remove the objective

from the camera and attached a compatible T-ring

(list of compatibility at the end of this document) –

not supplied.

Figure 1. Features.

1- Nosepiece adapter 1.25”;

2- Eyepiece body;

3- Extender fixing thumbscrews;

4- T-Thread body;

5- T-Threads;

6- Eyepiece fixation thumbscrew.

Figure 2.

A –Camera (DSLR);

B –T adapter;

C –Eyepiece;

D –Tele-extender.

Figure 3. Eyepiece is fixed inside the tele-extender.

Reproduction of part or all of the contents of this document in any form is expressly prohibited other than for individual use only. All text, images and labels are property of nimax Gmbh.