ASTRO-PHYSICS German Equatorial 1200GTO, Руководство пользователя

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Understanding the R.A. and Dec. Clutch Knobs
We suggest that you read this before assembling the remainder of your system.
1. What do they do?
The four R.A. and four Dec. clutch knobs depicted in the Assembly Diagram on page 6 have the function of
connecting the R.A. and Dec. axes to their respective drive worm wheel gears. Their function is progressive, from
no tension (axes free to move - as required during correct balancing of the telescope) to a completely "locked up"
state.
2. How can you find out what they really do?
As shipped, all 1200 mounts have all four R.A. and Dec. clutch knobs firmly hand tightened. This will give you a
good idea of the maximum tightness (clutch action) that can be achieved by hand effort alone. At this point, you
must bear in mind that for optimum performance all four clutch knobs on each axis (R.A. or Dec.) should be
tightened evenly with the same tension i.e. all four half tight, all four fully tight, etc.
In order to feel the effect of the clutch knobs, you may wish to partially assemble your mount. Fit together the R.A.
and Dec. assemblies plus mounting plate and counterweight shaft. Do not put scope and counterweights on at this
stage. With the above assembly (with the clutch knobs firmly hand tightened - "as shipped"), you can feel the
amount of force needed to move each axis by hand. Grab each end of the telescope mounting plate and move it
with a backward and forward movement of the Dec. axis. You will feel considerable resistance to this motion.
Perform the same operation on the R.A. axis by moving the counterweight shaft backward and forward. With a
well-balanced telescope, the above tightness of the clutch knobs will be sufficient for all normal conditions of use.
Now, if you proceed to mount up and balance your telescope, you can "feel" what this resistance in R.A. and Dec.
(movement backwards and forwards) is like when you make these motions from the eyepiece end of your
telescope as you would during normal use when slewing (pushing) by hand to acquire an astronomical object within
the field of view of your finder or scope.
3. How tight can the clutch be and can you do any damage by pushing against them?
The maximum tightness of this clutch system is 1/3 turn (with a 5/32 hex key) further in than the tension you can
achieve with the knobs by hand. You will see that each clutch knob has a 5/32 hex socket for tightening with a hex
key. With this extra 1/3 turn on each clutch knob, the axis (axes) will be considered completely "locked up" and you
should not attempt to push your scope by hand against this "locked up" resistance, or undue stress will be placed
on the worm wheel/worm and bearings.
However, if you are undertaking a very long astrophoto exposure, it is advisable to increase the pressure on each
clutch knob (with the 5/32 key) by about 1/8 turn past hand tight on Dec. and 1/8th turn past hand tight on R.A. You
may safely slew the scope by hand with this tension, however you will notice considerably more effort is required to
achieve movement. This is the absolute maximum tension that can be used for hand slewing. As a general rule, if
you have a big scope (7" or 8" refractor) with all the accessories, you will need more clutch tension than a 5" or 6"
scope.
WARNING! Resist the urge to over tighten the clutch knobs with the hex wrench. This will only cause them to
deform and lock into position. If you find that you are no longer able to adjust the tension and the knobs are locked
firmly in place so that the axis will not move, please refer to the Clutch Plug Replacement Section at the end of this
manual.
Balancing Your Telescope
For proper operation, the telescope must be adequately balanced along both axes. Start by balancing the tube assembly.
First, Balance the Declination Axis
1. Position the mount for balancing. Move the R.A. axis so that the counterweight shaft is pointing down. The
declination axis assembly will be in the meridian (this is the classic photographic pose for a German Equatorial).
Position the Dec. axis so the telescope tube is horizontal and pointing east.
2. Tighten the 4 R.A. axis clutch knobs.
3. Loosen the 4 Dec. axis clutch knobs (about 3/4 to 1 turn) so that the telescope moves freely about the declination
axis. Be careful because if your telescope is significantly out of balance, it may swing rapidly in the out-of-balance
direction!
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