Telescope is a Planewave PW1000. Software control is through Planewave's PWI4 software. This runs under Windows, and provides a graphical user interface, as well as an ASCOM driver and also a custom Planewave HTTP API. This is run from a Windows computer in the dome, pwi1m.

pwi1m has two network interfaces. One connects to the telescope internal network on 192.168.10.XXX. pwi1m is 192.168.10.40, the Maestro controller on the telescope is 192.168.10.50, and the OTA controller on the telescope is 192.168.10.60.

On starting PWI4, devices are controlled from the left panel, which has five tabs: Mount/Focus/Rotate/M3/Temp. You connect to the telescope using the Connect button on the Mount tab, and you can enable/disable the azimuth and altitude motors. On the Focus tab, you connect to the focuser and enable/disable it, and on the Rotate tab, you connect and enable/disable the rotator. On the Temp tab, you connect the OTA, which allows you to get temperature monitoring, control fans, etc. The M3 tab is used to position the tertiary to the Nasmyth ports: Port 1 is the port with the rotator and focuser.

You can slew the telescope using the SkyViewer tab: click on the desired location, then confirm with Goto button. You can also just enter coordinates directly on the Goto tab. Tracking should be started after the slew. You can monitor the tracking performance with the Tracking tab. Temperatures can be viewed on the Temperature tab. Finally, a camera can be controlled through the Camera tab; you need to select the camera (ASCOM or MaximDL), and then connect to it.

Software is implemented so that all devices can be controlled from a single command-line program running on a separate computer, using software in the APOsong repository. Given that all of the devices are on the internal APO network, the main control computer, song1m, is located on this network, and remote operation can be done using VNC with an openVPN or tunneling connection. On song1m, the software environment is set up for the song user.

The control software is run from a Python environment; APOsong provides commands to control telescope, camera etc., but you can also use all regular Python functionality, providing for a powerful environment. Within the APOsong software, interactive image display is enabled using the pyvista display tool and built-in, e.g. for the expose() command, but of course any other Python packages can be used interactively.

To access the software:

from aposong import *

The dome has motorized upper and lower slit sections. Control of the upper slit and dome rotation is done through a custom relay box on the S side of the dome constructed by the Autoscope Corporation; the lower slit is controlled through a box on the N side, designed and constructed by Dave Woods. There is a manual/automatic toggle to allow dome control either through switches on the side of the boxes, or via remote control. Relays to control the dome motors are 24V relays and are activated by setting input control lines to ground. The 24V power is supplied externally.

There is an encoder coupled to the motor drive shaft.

There is a magnetic home sensor installed on the E side of the dome; the home position when the magnet on the dome lines up with the sensor places the slit at an azimuth of 80 degrees.

Dome control is implemented through software running on a Raspberry Pi (dome1m). Initial implementation controls dome motors through the Autoscope box with Opto 22 relays, but goal would be to just control the dome relays directly. The Raspberry Pi has a RELAYPlates card with 7 relays, which control shutter direction, shutter power, dome direction, dome power, and watchdog reset. These relays connect the control lines to ground.

The dome encoder gets +5V and ground from the RPi, and receives 5VDC signals from the A and B phases of the quadrature encoder. These are wired into RPi GPIO ports through a level converter that converts 5V to 3.3V. DC +5 and ground are connected to RPi power, A and B outputs are connected to level shifter input channels; level shifter output channels are connected to RPi GPIO pins. An independent ground from the cable shield may be very important, do not ignore!

The home sensor gets +5VDC and ground from the RPi, and receives a signal on a GPIO port that is normally low, but goes high when the home magnet is in proximity to the sensor.S

Dome control is implemented through software running on a Raspberry Pi (dome1m).

Low-level functions are implemented in the APOAshDome.py module. An ASCOM Alpaca interface was implemented using the templates from the AlpycaDevice package. Software is archived at https://github.com/holtzmanjon/APOAshDome.

User account on dome1m is ocs.To run Alpaca device, cd APOAshdome/device, python app.py