Monday 28 October 2019

Ethernet over mains remote imaging with AstroDMx Capture for Linux and a Canon EOS 4000D DSLR

An experiment with remote DSLR imaging with Ethernet over mains via powerline ethernet adapters.


Our observatory is 20m from the house and we routinely run an extension cable out to the observatory to power the mount and an imaging laptop.

We used a Tenda P200 kit pair of powerline Ethernet adapters. The adapters each have a UK plug and an Ethernet socket. One adapter was plugged into the mains in the house near to the router and an Ethernet cable was connected between the adapter and the router. The other adapter was connected to the end of the extension lead in the observatory and an Ethernet cable was connected between the adapter and the imaging laptop in the observatory, which was running Ubuntu Linux 19.10. This gave Ethernet access to the observatory laptop. The observatory laptop was covered by a plastic printer cover to prevent condensation from forming on the keyboard.

Powerline Ethernet adaptor


Nicola configured the observatory computer was with a fixed IP address within the same subnet as the main network. The observatory computer was running a VNC server that ships with the OS, which provided a mechanism to access the remote computer's desktop and fully control AstroDMx Capture. The observatory computer was setup as shown in the following screenshot.



A laptop in the house running Fedora Linux was then able to access the observatory computer's desktop by using a standard VNC client application and fully control the desktop of the observatory computer. This allowed the computer in the house to see the live preview and remotely operate the controls of AstroDMx Capture for Linux.

A motor-focuser-adapted Bresser Messier AR 102xs f/4.5 ED refractor was mounted on the HEQ5 Synscan GOTO mount in the observatory. Using a 2" adapter, fitted with a light-pollution filter, a Canon EOS 4000D DSLR was placed at the prime focus of the refractor. The DSLR was USB tethered to the observatory Ubuntu laptop.

30 x 90s exposures at ISO 6400 were captured of M31 with matching dark-frames and 22 x 90s exposures were captured of NGC7789, Caroline Herschel's White Rose cluster in Casseopeia.
The camera RAW images were stacked in Deep Sky Stacker and post processed in the Gimp 2.10.

Screenshot of the Fedora laptop controlling AstroDMx Capture for Linux on the observatory Ubuntu computer, capturing data on the Andromeda Galaxy

Screenshot of the Fedora Laptop controlling AstroDMx Capture for Linux on the observatory Ubuntu computer, Capturing data on the White Rose Cluster


The Andromeda Galaxy

NGC7789 The White Rose cluster

On a cold night, this system only required occasional visits to the observatory to check on things.