# Saddle Plate Rotation

## Step 1: Find zero position

The `Zero` position (aka `Home` position) on an equatorial mount is the position at which the counterweight shaft points to the ground, the telescope is at the highest position with its axis parallel to the polar axis and the telescope is pointing to the celestial pole.

<figure><img src="/files/VPnLHtPB7vlbCcBm07aO" alt=""><figcaption></figcaption></figure>

Plug in the 12V DC power supply to the DC12V power socket. Connect the hand controller to the HBX port on the mount side panel. Turn the mount power on.

<div align="left"><figure><img src="/files/kydnNgFwL9XrA9OimBaq" alt=""><figcaption></figcaption></figure></div>

Go to `zero position` in the hand controller and select `search zero position`. The mount will start to slew slowly to search and set the mount to the `Zero` position. When the mount has found the `Zero` position, the hand controller will ask if you want to `calibrate the zero position`. Press enter to confirm. Make a note of the North facing side of the mount top plate.

&#x20;

<figure><img src="/files/CHcB4Kev6uRmIYFnckir" alt=""><figcaption></figcaption></figure>

The way the camera box hardware is designed, the cameras would face 90 degrees away from the celestial pole when the mount is at the `Zero` position.

<figure><img src="/files/wYdbaBwvhUIykHtlgbki" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
If your camera box is facing in the direction of the celestial pole at the zero position, you can skip doing the mount saddle plate rotation as described below.
{% endhint %}

The saddle plate of the mount needs to be mechanically rotated by 90 degrees (as shown below) so the cameras are facing North when the mount is at `Zero` position.

<figure><img src="/files/IiP3vqmrkpKKpM3H01xY" alt=""><figcaption></figcaption></figure>

## Step 2: Rotate saddle plate

Turn off the mount. Disconnect the power supply. Remove the screws in the order shown below, rotate the saddle plate, and reassemble the top plate.

<figure><img src="/files/nahQw1hejACwHj4bsvNG" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/bxwzxMvGKOCkA2zAYBed" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
Make a note of which cable corresponds to which port.
{% endhint %}

<figure><img src="/files/ZAJdNcJRt5yf6vgHIYNN" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
Only the four center screws need to be removed in order to remove the saddle.
{% endhint %}

{% hint style="warning" %}
The screws holding the saddle in place might be tight. It's best to have someone firmly grip the saddle while attempting to unscrew otherwise it's possible to rotate the saddle itself, which will cause the internal gears to grind against each other.
{% endhint %}

<div align="left"><figure><img src="/files/hUoY6wmWa1aaKStMNmhW" alt=""><figcaption></figcaption></figure></div>

<div align="left"><figure><img src="/files/IMO2EmWGL91vtX2wXnv9" alt=""><figcaption></figcaption></figure></div>

{% hint style="warning" %}
Be careful when re-attaching the screw on the underside (see image below). If you screw it in all the way it has the potential to grind against the underside of the saddle plate.
{% endhint %}

<figure><img src="/files/e01rAJExztDEuiCZMyrh" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/jrsdG7dCVoZV3jWrqWyy" alt=""><figcaption></figcaption></figure>

Put back all screws and reassemble the saddle plate.

{% hint style="info" %}
The small box that has the wires can be re-attached on either side of the saddle plate.
{% endhint %}

## Step 3: Test new `Zero` position

Plug in the 12V DC power supply to the DC12V power socket. Connect the hand controller to the HBX port on the mount side panel. Turn the mount power on.

Go to `zero position` in the hand controller and select `search zero position`. The mount will start to slew slowly to search and set the mount to the `Zero` position. When the mount has found the `Zero` position, the hand controller will ask if you want to `calibrate the zero position`. Press enter to confirm. Check to see if the new `Zero` position is rotated by 90 degrees compared to the `Zero` position seen in [#step-1-find-zero-position](#step-1-find-zero-position "mention").

<div align="left"><figure><img src="/files/4EsL7NuJtMhfVyhO6rlZ" alt=""><figcaption></figcaption></figure></div>


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