There is a spectrograph computer, spec1m, that controls the spectrograph camera (QHY600) and the spectrograph focuser (Esatto). The computer is a OnLogic CL210-G, same as the pwi1m computer, running Windows 11.

The original QHY is liquid cooled, but the camera has no internal protection against overheating should the cooling loop fail. To try to add a layer of safety, we have a couple of thermocouples taped to the body of the camera. We also run the spectrograph power through a Peltec watchdog, and have a relay that resets the watchdog every minute if the thermocouples are reading acceptable values.

The thermocouples are read by a USB device, a Yoctopuce. The relay is a Kmtronix 2-channel USB relay, controlled by serial interface (COM7). If the Yocto software is not running, the QHY 600 should power off after a few minutes. If it is running, the watchdog reset should only be triggered if the thermocouple readings are below a critical value, and if the chiller (see next paragraph) is not reporting any faults.

In April 2026, we installed a TCube Edge 300 from Solid State Cooling Systems to chill and pump fluid through the QHY camera. The TCube has a serial interface (COM8) that allows one to check status, set fluid temperature, etc. (see manual).

The focuser is a PrimaLuce Esatto focuser. It has an ASCOM driver and connects at COM5.

The PrimaLuce Esatto focusser has some internal lights that scatter into the spectrograph at a low level. The only way to remove these is to power the focuser down. This is plausible given that the spectrograph is supposed to be stable. We have run the USB to the focuser through a WandererAstro Ultimate PowerBox V2, which allows for turning the USB off and on, via a simple serial interface that I wrote an Alpaca switch driver for.

The Esatto focusser is connected on port 3 of the Wanderer. The power/USB can be cycled through the Alpaca switch drive (SW.SetSwitchValue(2,0) to turn off, SW.SetSwitchValue(2,1) to turn on).

We run the QHY600 USB through the Wanderer as well, in case we ever need to reconnect the USB. It is plugged into port 1 (so accessed through SW.SetSwitchValue(0,0|1)).

The entire spectrograph is enclosed in a box made of 2“ Thermasheath foam insulation (R13.1) purchased from Distribution International in El Paso. It is made of 7 different panels; the top side panels are designed to be removable. There is a pass-through for the fiber on one end, and for cables to the camera, focuser, and thermal sensors on the other end.

The box is put together using PVC along the panel edges, and bolting/clipping panels to each other.

There is no bottom to the box, it rests on a couple of foam yoga mats.

We also have a pair of Avtech TemPageR units for monitoring temperatures. Each box has a sensor inside the box, and connectors for two external thermocouples (?). These four sensors are placed in various location inside the spectrograph box.

Here is a photo of the system components.