Explore Scientific 0116950, Instruction Manual

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Illustration 9: Mirror adjustment by using the adjustment screws
Let's look at the image in a typical Newtonian reflector telescope with a usual aperture ratio (i.e. a
smaller aperture ratio). When the observer looks through the telescope (without eyepiece), the eye of
the observer, the secondary mirror, primary mirror and eyepiece extension appear relatively exactly
centered in the middle. (see figure 7).
With the fast aperture ratio of Newton telescopes, on the other hand, the secondary mirror must be off-
set in two directions from the centre: 1. away from the focuser and 2. towards the main mirror (by the
same amount).
This so-called "offset" is a few mm in both directions. Remember that these settings were made at the
factory before the telescope was shipped. We will only mention it here if you have seen corresponding
images on the Internet. For checking and possibly new optical collimation, please proceed as follows:
1. Look into the eyepiece drawer without the eyepiece. The secondary mirror appears round and in
the middle. If it is not in the center, center it with the two collimation screws on the back of the sec-
ondary mirror mount.
2. If the reflection of the secondary mirror is not exactly in the center of the primary mirror, adjust the
primary mirror with the 3 collimation screws located in the mirror box above or left and right below
the primary mirror.
Main mirror adjustment
Illustration 10: Main mirror adjustment with collimation tool
If the secondary mirror and the reflection of the primary mirror (2, fig. 7) be centered, but the mirror im-
age of your eye and the reflection of the secondary mirror (5, fig. 7) are not centered, the primary mir-
ror must be adjusted. To do this, insert the supplied adjustment tool over one of the three hexagon
socket adjustment screws visible on the side and above the main mirror. If you turn and swivel the ad-
justment tool a little, you will notice that it will soon snap into the hexagon socket of the screw. Now
you can adjust the main mirror by turning the adjustment tool. (See Figure 8) Practice this a little until
you get a feel for what a turn of one of the adjustment screws in the eyepiece extension will do. When
you have placed the reflection of the eye in the position shown in Fig. 8 the rough adjustment of the
telescope is completed.
Fine adjustment