Socket Mobile GTOCP2 - Manual (Page 10)

10
Assemble Polar Axis Assembly to Pier or Tripod
In order to track the motion of astronomical objects, the polar axis must be positioned so that an imaginary line drawn
through the center of the axis points toward the celestial pole. At this stage of the assembly process, you want to position
the mount so that it points roughly north.
1. Remove the four (4) hand knobs on the pier top adapter and keep them close at hand.
2. Prior to lifting the polar axis assembly into place, turn the fine azimuth adjustment knobs so that the space
between them is wide enough to allow the center azimuth block to fit easily between them. Ensure both pier top
and polar axis assembly mating surfaces are clean and free of dirt.
3. Place the polar axis assembly onto the pier top adapter so that the center azimuth block fits between the fine
azimuth adjustment knobs.
4. Move the base of the polar axis assembly so that the threaded holes of the pier top can be seen through each of
the four slots.
5. Thread the four hand knobs loosely in place (you will tighten these later after polar alignment).
Altitude and Azimuth Adjustments - Rough polar alignment
For rough polar alignment, your goal is to sight the celestial pole when looking through the polar alignment sight hole in the
center of the polar axis. You will need to make altitude (up/down) and azimuth (side-to-side) adjustments to the position of
the mount.
We recommend that you do your rough polar alignment with the R.A. axis only since you will be making major adjustments
to the position of the mount at this time. The remainder of the mount, telescope and counterweights would add considerable
weight and require more hand effort. Later, you will do your final polar alignment with the telescope and counterweights
attached, but the adjustments will be small.
1. If the R.A. encoder housing and encoder adapter are installed (part # ENC1200 - Mounted Encoders to use with
Digital Setting Circles - are available as an optional purchase), you may remove them to complete these steps.
Please refer to the section entitled “ Installation of Encoders and Encoder Housings – 1200 Mount“. Alternatively,
you can simply sight up the side of the polar axis to see Polaris.
2. If you examine the polar axis assembly, you will see that the center of the R.A. shaft is hollow. If you have not
done so already, loosen (1/2 turn) the four pier knobs.
NOTE: If you have already attached the Dec. axis, remove the sight hole cover and rotate the internal Dec. shaft
by moving the top of the Dec. axis (or the cradle plate if it is attached) to reveal the sight hole that has been drilled
into it. Now, you can look through the shaft to the other side.
3. Azimuth adjustments: Move the entire pier or tripod east or west until the mount is oriented approximately
towards the pole (an imaginary line drawn through the hollow shaft). Use the two fine azimuth adjustment knobs,
one on each side of the mount, to make adjustments. You must back off the opposing azimuth knob in order to
move the other knob in that direction. Please refer to Diagram 4.
One turn of the azimuth knob is approximately 0.53 degrees (32 arc minutes).
4. Altitude (latitude) adjustments: Loosen the altitude locking knobs. Move the polar axis up or down with the large
altitude adjustment knob located in the front of the polar axis assembly. The tommy bar can be positioned in any
of the threaded holes located in the altitude adjustment knob. Use this bar to help you turn the knob. Please refer
to Diagrams 3 and 4. We have found that fine altitude adjustments also can be made by using the turnbuckle on
the north leg of our pier, if used.
One turn of the altitude knob is approximately 0.5 degrees (30 arc minutes).
5. Continue your azimuth and altitude adjustments until you can sight Polaris in the polar alignment sight hole. At
this point, you have achieved rough polar alignment, which may be sufficient for casual visual observations if you
are not planning to slew to target objects with the keypad. When the R.A. motor is engaged, it will compensate for
the rotation of the earth and keep the target object within the eyepiece field of view. Your target object will slowly
drift since polar alignment at this stage is only approximate. However, you can make corrections with your hand
controller as we will discuss later.
6. Tighten the altitude locking knobs by hand.
7. Tighten the pier knobs firmly by hand.