Multi-mount astro

Connect a hybrid LX200-like mount where RA is driven by a SkyWatcher SynScan mount and DEC by a DIY Arduino + TMC2209 controller.

About this project

This repository exposes one LX200-compatible endpoint while coordinating two different physical axes:

• RA is driven by AxisRA on top of SkyWatcherMotor.
• DEC is driven by AxisDEC on top of TMC2209Motor.
• Combiner joins both axes and feeds SkyLX200, so INDI clients can treat the setup as one mount.

The current Python runtime is built from:

• LX200SimpleServer for TCP/LX200 framing;
• LX200Handler / SkyLX200 for LX200 command dispatch;
• Combiner for two-axis coordination and polar-compensation feedback;
• AxisRA and AxisDEC for mount-position tracking, motion queuing, and motor compensation;
• SerialLine for the low-level serial transport to both controllers.

The DEC firmware lives in telescope_dec/src/main.cpp. It exposes a small line-based protocol (status, position, speed, acceleration, direction, delta, run, stop, mode, set) that the Python TMC2209Motor backend uses directly.

Scheme

KStars / Ekos / INDI
        |
        v
   LX200 client
        |
        v
 LX200SimpleServer
        |
        v
     SkyLX200
        |
        v
     Combiner
      |     |
      |     `--> AxisDEC --> TMC2209Motor --> Arduino firmware --> TMC2209 --> DEC axis
      |
      `--------> AxisRA  --> SkyWatcherMotor --> SynScan mount

Coordinate system

Case	RA Rate	RA Ticks	RA mount	Dec Rate	Dec Ticks	Dec mount
Mount didn't track, keep still	0	const	↑	0	const	const
Mount base track	1	↑ == T	const	0	const	const
SLEW / GOTO
East slew	-800	↓↓	↑↑	0	const	const
West slew	800	↑↑	↓↓	0	const	const
North slew	1	↑	const	> 0	↑↑	↑↑
South slew	1	↑	const	< 0	↓↓	↓↓
GUIDE
East guide	0..1	↑ < T	const	0	const	const
West guide	> 1	↑ > T	const	0	const	const
North guide	1	↑	const	> ~0	↑	0
South guide	1	↑	const	< ~0	↓	0

RA: 00:00:00 .. 23:59:59 DEC: -90*00:00 .. 90*00:00

Expected runtime behavior:

• the mount starts in tracking mode;
• SYNC updates the logical mount coordinates;
• GOTO moves both axes toward the target;
• HALT returns the affected axis back to tracking.

Repository layout

• src/lx200: LX200 protocol parsing and TCP server.
• src/sky: axis state machine, combiner, polar compensation, coordinate math.
• src/skywatcher/motor.py: SkyWatcher/SynScan RA backend.
• src/tmc2209/motor.py: Python backend for the Arduino DEC controller.
• src/web_control: standalone web monitor infrastructure.
• telescope_dec/src/main.cpp: AVR firmware for the DEC controller.
• src/tests/hw: active hardware and end-to-end tests.
• src/tests/units: active fast tests.
• src/tests/old: archived tests that are kept for reference and are not collected by default.

Current TODO / known gaps

• Pole crossing is still incomplete: when DEC reflection crosses the pole, RA should be mirrored by +12h as well.
• LX200SimpleServer still allows multiple concurrent clients against the same handler and has no connection-level disconnect hook.
• MS still returns a simplified boolean status instead of a full LX200 slew result code.
• Step-based typed units such as steps/s are not modeled explicitly in sky.physics yet.
• RA and DEC backend status contracts are still similar but not fully unified.
• The web monitor server is started separately and currently uses an empty registry in src/__main__.py.

Tests

Default pytest discovery uses src/tests/hw and src/tests/units. Hardware suites expect real devices and serial ports; fast checks live under src/tests/units. A more detailed overview is kept in TESTS_PLAN.md.