February, 2012

Modes, Cameras, and Secondaries

The wavefront sensor software runs in 3 major modes: F9, F5, and MMIRS. Each mode corresponds to an entirely different camera and associated wavefront sensor hardware. Each mode involves a different set of motors and schemes to move the camera (or pick-off mirror) into the optical path and each has its own specific GUI to control exposures, motors, and whatever is needed to obtain images to be analyzed by the rest of the software. Only MMIRS allows continuous wavefront sensing while observing, the others need to be switched in and out.

f9 camera The operator interacts with f9wfs_gui, which is a ruby script to allow control of the necessary things. To make an exposure, this script does ssh to the machine f9wfs (as user "tim"!!) to run the script "get_apogee", then uses scp to transfer the file.

The machine f9wfs runs linux, and has a special PCI card that interfaces to an Apogee camera.

f5 camera The operator interacts with f5wfs_gui, which is a ruby script to allow control of the necessary things. To make an exposure, this script runs the bash script "getimage", which uses netcat to send commands to port 3001 on the machine wavefront. It looks like netcat is actually using the MSG protocol in a brutal yet utilitarian way. Standard output from netcat is redirected into the desired file.

The machine wavefront runs windows, and was delivered to us from SAO as a turnkey system. Ultimately the f/5 wfs output comes from an SBIG camera. This machine uses Cygwin to run some of the software components, but by and large is a black box to the MMT software staff. One concern is to keep some kind of disk image as a backup for the inevitable day when some hardware failure takes place.

MMIRS camera The operator interacts with mmirs_gui, which is a ruby script to allow (you guessed it!) control of the necessary things. This mode has the most sophisticated setup (and could be a model for the rework of the other modes). An SRV lookup is done on the resource "mmirs-wfs", which at the present time resolves to port 9876 on tcs_server (i.e. hacksaw). To control the camera a service "mmirs-wfs-server" (managed by mmtserv) must be running. Details beyond this are unknown to the current author.