ASTRO-PHYSICS German Equatorial 1200GTO Use and care manual

Step 1 - Remove the declination axis assembly,
GTO control box unit and any cables from the
mount. If your mount has the GTOCP1 control box,
you may elect to leave it attachted since it is more
difficult to remove than the GTOCP2 control box.
You may leave the right ascension assembly on
your pedestal, pier or tripod for most of the
upgrade. Have a table close by to set parts on.
Please note that the polar axis you will be removing
weighs approximately 36 pounds. Although not
mandatory, it would be best to have an assistant for
this upgrade.
Step 2 – Look at the interface between the polar
fork and right ascension housing. There are 4 flat
washers that will be dropping out as disassembly
takes place. Be aware of their location. All four are
the same size and thickness.
Step 3 – Using a ¼ inch hex key, remove the lock
knobs from both sides of the polar forks. The
washers resting between the forks and the housing
may fall out at this time. Be prepared to catch
them. If they do not drop out, release the torque on
the rear screws approximately one turn to release
them. (3-A) DO NOT remove the rear screws at
this time.
There is a possibility that the knob under the
worm drive bracket will hit the end of the cut out in
the bracket. (3-C) In this case the length of the
screw in the knob is slightly too long. Place a piece
of tape on the bracket to prevent scaring of the
parts.(3-D) Rotate the knob out until it hits the tape
and with a 1/4 inch hex key in the center screw, try
to “wiggle it free. If this does not work try the
following. Remove the set screw in the knob using
a 5/64 hex key. (3-E) Push into the set screw hole,
as deeply as possible a 1/8 inch hex key. Make a
cushion of cloth or paper and locate it under the
hex key and fork stiffener. Using a 1/4 inch hex
key attempt to break free the 5/16 socket head cap
Upgrade replacement of
1200GTO Polar Forks S1200PF-B
3-A3-A 3-B3-B
3-D3-D3-C3-C
3-E3-E 3-E3-E
2-B2-B
2-A2-A
1-A1-A
4-A4-A 4-B4-B
Please gather the following tools
and materials to aid in the
replacement process.
¼ inch hex key
1 inch wide masking or electrical tape
Wood 2x4, maximum length 9 inches
Approximately 10) 3 ½ x 5 inch
pieces of single corrugation
cardboard
3/32 inch hex key
3/16 inch hex key
Table near telescope pier.
06/22/2004
Although the installation of the new forks would seem to
be fairly obvious the weight of the RAAxis, location of
washers, awkwardness of position and gravity all add
complexity. We advise that you follow these instructions,
rather than “Wing it”. This will assure that all of the
pieces are assembled back properly and will prevent
damage to the paint finish.

screw in the center of the knob. (3-E) Turn the
wrench counter- clockwise. Be very careful. If you
succeed in breaking the screw free, rotating it out
approximately 1/16 inch should be sufficient to
allow for easy removal of the knob. If not, contact
customer service.
Step 4 - Remove the rear pier top knob from under
the right ascension housing.
Step 5 - Place a wood 2x4 approximately 9 inches
long under the housing. Take up the remaining gap
with precut pieces of cardboard. Push the
cardboard in tight. How many pieces you will need
will depend on your latitude. Customers higher
than 42 degrees may want to lower their axis to
accommodate at least two pieces of cardboard. If
you have a 1200GTO with digital encoders the
encoder housing will have to be removed to get the
wood block into place.
Step 6 - Place a strip of tape over the top face of
the forks on both sides to protect the paint.
Step 7 - With an assistant, if possible, grasp the
mount firmly at the top and remove one of the two
rear pivot screws. Use a ¼ inch hex key. The
housing will shift, but settle on the cardboard. The
washer between the housing and forks will fall out.
Step 8 - Firmly brace the housing with your arm
and remove the second screw. The housing is now
free, resting on both the cardboard brace and
altitude adjuster.
5-A5-A 5-B5-B
5-C5-C 5-D5-D
6-A6-A 6-B6-B6-A6-A 6-B6-B
7-A7-A 7-B7-B
8-A8-A
8-B8-B
8-C8-C

Step 9 - Grab the housing with both hands and lift
out of the forks. Remember that the weight of the
housing is approximately 36 pounds.
Step 10 - Using a 3/16 inch hex key remove your
altitude bracket assembly.Take note that the pivot
screw aligns with the curved front surface of the
bracket. Make a record of the screw locations
before removal. All four screws must be removed.
Have an assistant spread the forks if there is too
much pressure on the bracket.
Step 11 - Remove the three remaining pier top
knobs. Lift the polar forks from the pedestal, invert
and set on a table. Remove the azimuth adjuster
or pair of adjusters depending on which version
you own. The new one part azimuth adjuster
(shown in photo11-A,B) is available for sale as
upgrade. Part number S1200AZA-A.
Step 12 - Remount your azimuth adjusters on the
new polar fork assembly. If you have the older two
part adjusters (shown in photo12-A,B) take note
that as the screw is tightened the azimuth threaded
rod should be parallel with the azimuth block cut
out. Use a 3/32 hex key for the azimuth
replacement.
Step13 - Place the new forks back on the pedestal.
Put three of the four pier top knobs back in place.
Remount the altitude bracket at the same hole
setting as the original forks. Note that the pivot
point is at the front curved surface of the bracket
(Step 10). Start with that screw first. Leave all four
screws loose at this stage.
9-A9-A
9-B9-B
10-B10-B
10-A10-A
10-C10-C
11-A11-A 11-B11-B
12-A12-A 12-B12-B
13-B13-B13-A13-A
13-C13-C

Step 14 - Put both rear pivot screws back in place,
protruding slightly through the forks. Mount the
pivot washer on each screw and secure with a
piece of tape. Place the tape well away from the
hole in the washer so it will not trapped by the
housing. Also make it long enough to be retrieved
later.
Step 15 - Place tape on the top front faces of the
both sides of the forks.
Step 16 - The pivot point of the new fork assembly
is ¾ inch higher than the older version. To
accommodate the new height add 5 sheets of
single corrugation cardboard to the previous 2x4
and cardboard stack. The combination should
place the housing and fork holes close to
alignment.
Step 17 - With an assistant, place the housing back
into the fork, resting it on the altitude adjuster and
wood/cardboard stack. Remove one pivot screw
and look in the hole for the threaded hole in the
housing. Make adjustments and start the first
screw a couple of threads. Look in the second
hole, align housing and start second screw. Rotate
both screws into a light stop. Do not lighten at this
stage. The cardboard can be crushed to lower the
housing with full support. Note that the first screw
may be hard to get in more than a few threads if
the opposite side is too far out of alignment. If the
washer should move and block access to the
housing hole, it can be moved out of the way with
one of the smaller hex keys.
14-A14-A 14-B14-B
15-A15-A
16-A16-A
17-A17-A 17-B17-B
17-D17-D17-C17-C
17-F17-F17-E17-E 17-G17-G

Step 18 - Remove the tape from the forks and
washers.
Step 19 - Replace the fork knobs on both sides.
The knob washer can be guided into place. Put the
threaded portion of the knob though the curved
hole in the housing. Spear the washer with the
knob and drag the tip lightly along the housing
surface to the threaded hole. If you had trouble
removing the knob under the worm drive back in
step 3, place tape on the mounting bracket.
Loosen the altitude bracket and pivot screws. Use
the stick again if needed.
Step 20 - When finished, tighten all six screws and
the two knobs. Remove the wood/cardboard stack,
any forgotten tape and replace the last pier top
knob. If the mount had an encoder replace that
also. Enjoy the features of the new polar forks.
06/22/2004
WAP LK
18-A18-A
19-B19-B19-A19-A
19-C19-C 19-D19-D
19-E19-E
20-A20-A 20-B20-B
20-C20-C