teldaemon_astrosib is a daemon that controls an Astrosib telescope equipment via a serial line or virtual serial port over TCP. It provides a TCP/UNIX socket interface for clients, integrates with a weather_proxy to enforce safety rules, and generates a FITS‑header file with current telescope status.

Features

Shutter control – open / close
Focuser control – absolute move, relative move, stop
Cooler control – switch primary mirror cooler on/off
Heater control – switch secondary mirror heater on/off
Status reporting – shutters state, focuser position, cooler/heater status, mirror and ambient temperatures
Weather integration – automatically closes shutters and prevents opening when weather is bad or data is stale
Manual override – via SIGUSR1 (forbid) / SIGUSR2 (allow) signals
FITS header file – writes current telescope state into a FITS‑style header file (e.g., for later use by image processing pipelines)
Network interface – supports both INET (TCP) and UNIX domain sockets
Daemon mode – forks, writes PID file, restarts child on crash

Command‑line options

Option	Argument	Default	Description
`-h`, `--help`	–	–	Show help
`-v`, `--verbose`	–	0	Increase verbosity (each `-v` adds 1 level)
`-l`, `--logfile`	path	–	Full path to log file (otherwise stderr)
`-n`, `--node`	string	–	Node specification: IP, `name:IP`, or path for UNIX socket. For anonymous UNIX socket use `\0path` or `@path`.
`-u`, `--unixsock`	–	0	Use UNIX socket instead of INET
`-m`, `--maxclients`	number	2	Maximum number of simultaneously connected clients
`-p`, `--pidfile`	path	`/tmp/teldaemon.pid`	PID file path
`-d`, `--serialdev`	path	–	Full path to serial device (e.g. `/dev/ttyUSB0`)
`-b`, `--baudrate`	speed	9600	Serial baud rate
`-t`, `--sertmout`	microseconds	1000000 (1 sec)	Serial read timeout (µs)
`-H`, `--headerfile`	path	`/tmp/telescope.fits`	Output file for FITS‑style header
`-N`, `--telname`	name	`Astro-M (1)`	Telescope name inserted into the header
`-M`, `--headermask`	bitmask	`0xff` (all bits set)	Mask controlling which information appears in the header. Use `-1` to list bits.

Header mask bits (used with `-M`)

Bit	Description
0	telescope name
1	focuser status
2	cooler status
3	heater status
4	external temperature
5	mirror temperature
6	measurement time

For example, if you are using an external focuser and want to prevent the possibility of its data being overwritten by the telescope data, use a mask -M125 (alternatively: -M0x7D or -M0b1111101).

Socket protocol

The daemon listens for text‑based commands on the configured socket. Each command returns one or more lines of output, terminated by newline (\n).

Commands

Command	Description	Example
`focrel <steps>`	Move focuser relatively (negative = inward, positive = outward)	`focrel = -500`
`focabs <position>`	Move focuser to absolute position (0 … 65000)	`focabs = 32000`
`focpos`	Get current focuser position	`focpos` → `focpos=12345`
`open`	Open shutters (only if weather permits and observations not forbidden)	`open`
`close`	Close shutters	`close`
`status`	Get shutters state, temperatures, last error, and safety flags	`status` → (see example below)
`focstop`	Immediately stop focuser movement	`focstop`
`cooler <0/1>`	Switch primary mirror cooler off (0) or on (1)	`cooler = 1`
`heater <0/1>`	Switch secondary mirror heater off (0) or on (1)	`heater = 0`
`dtime`	Return server’s current UNIX time (seconds with milliseconds)	`dtime` → `UNIXT=1704067200.123`
`help`	Show available commands (default handler)	`help`

Each setter returns an OK answer in case of success or error code like BADVAL for bad value of setter.

Example `status` response

status=closed
measuret=1779086249.480
mirrortemp=6.2
ambienttemp=6.3

status can be opened, closed, intermediate or unknown.
measuret is the time when the status was last read from the hardware.
errored_command appears if the last attempted command failed.
FORBIDDEN appears when observations have been manually disabled (SIGUSR1).
BADWEATHER appears when weather proxy reports unsafe conditions.

Weather integration

The daemon retrieves weather data via the weather_proxy shared memory interface (get_weather_data()).
Safety rules:

If weather.forceoff, weather.rain, or weather.weather > WEATHER_TERRIBLE → shutters are closed and opening is blocked.
If the weather data is older than 900 seconds (WEATHER_LOST) → treated as lost communication → shutters are closed and blocked.
When weather becomes good again, the daemon automatically resets the BADWEATHER flag and allows normal operation.

Signal handling

Signal	Effect (in child process)
`SIGUSR1`	Forbid observations – close shutters and block open
`SIGUSR2`	Allow observations – remove manual block
`SIGTERM`	Stop the daemon and remove PID file
`SIGINT`	Same as `SIGTERM`

FITS header file

The daemon writes a text file (default /tmp/telescope.fits) with FITS‑like keyword/value pairs. The file is updated every polling cycle (every 2 seconds) and can be used by external pipelines to record telescope state.

Example content:

TELESCOP= 'Astro-M (1)'         / Telescope name
TELSTAT = 'closed'              / Telescope shutters' status
TELCOOLR= 0                     / Primary mirror cooler status: 0/1 (off/on)
TELHEATR= 0                     / Secondary mirror heater status: 0/1 (off/on)
TDOME   = 6.3                   / In-dome temperature, degC
TMIRROR = 6.0                   / Mirror temperature, degC
TTELMEAS= 1779086301.494        / Measurement time: 2026-05-18 09:38:21

The file is created atomically using mkstemp() + rename().

Building and dependencies

Dependencies

libusefull_macros – common macros and helpers
libweather_proxy – shared memory weather data
pthread, libc

Build

git clone --depth=1 https://github.com/eddyem/small_tel.git
cd small_tel/Daemons/teldaemon_astrosib
make

The resulting binary is teldaemon_astrosib.

Installation

Copy the binary to a suitable location (e.g. /usr/local/bin).
It is recommended to run the daemon as a system service (using init script, e.g. in /etc/local.d/) so that it starts automatically at boot.

Usage example

Start the daemon with a UNIX socket and weather‑aware header:

teldaemon_astrosib -u -n "/var/run/teldaemon.sock" \
                   -d /dev/ttyUSB0 -b 115200 \
                   -H /var/state/telescope.fits \
                   -N "Astrosib-500" -M 0x7f

Connect to the socket using socat, nc or my tty_term:

socat UNIX-CONNECT:/var/run/teldaemon.sock -
> status

Send SIGUSR1 to forbid observations (e.g. before maintenance):

kill -USR1 $(cat /tmp/teldaemon.pid)

Notes

The serial protocol is specific to Astrosib hardware (commands like FOCUSERGO?, SHUTTEROPEN?1,1,1,1,1, etc. are hard‑coded).
Focuser absolute position range is 0 … 65000 (values outside this range are ignored).
The daemon polls the telescope every 2 seconds (T_INTERVAL). During that interval it also processes client requests and checks weather.
If the serial device becomes unresponsive, the status will show unknown and the header will not be updated.

License

GNU General Public License v3.0 or later.
See the LICENSE file in repository's root directory or http://www.gnu.org/licenses/ for details.

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teldaemon_astrosib