OnStep for EQ5 (SkyWatcher) Mount

Adapting EQ5 (SkyWatcher) telescope mount or similar types to OnStep goto controller, by Howard Dutton project.

Accessories recommended

• OnStep Mini 2.0 Cotroller and Box on base MiniPCB2 and Teensy3.2

or

• OnStep STM32 Controller and Box on base STM32 Blue Pill
• OnStep SHC Smart Hand Controller

BOM

2x JK42HM40-1684 NEMA17 0.9 Degree Stepper Motor 1.68A

2x GT2 Timing Belt 6mm wide 2mm pitch 136mm-2GT 68 teeth

2x GT2 Timing Pulley with 16 Teeth and Bore 5mm for 6mm belt

2x GT2 Timing Pulley with 40 Teeth and Bore 6mm for 6mm belt (Optional)

1x M8x15mm Inbus screw

1x M8x40mm Inbus screw

2x M8 nuts

9x M3x10mm Inbus screw

1x M3 Assortmen

2x M4 worm

2x M3 nuts

2x M4x20mm Hex Head screws

2x M4 wing nuts

2x M4 Assortmen

18x 2x6mm self-tapping screws

2x RA and DEC PCB

2x RJ14 6P6C Right Angle PCB Jacks

2x JST B4B-XH-A socket

1x 3mm Red LED and (1kΩ rezistor in STM32 case)

1x 3.5mm Stereo jack and cable

Optional

• LUX Photo Case AKV-115
• ZWO ASI AIR

OnStep 2.22 Config for TMC2130 drivers (Vref=1.6V)

// Axis1 is for RA/Az

// calculated as : stepper_steps* micro_steps* gear_reduction1* gear_reduction2/360 // EQ5 : 400* 64* 2.5* 144/360 = 25600.0 #define StepsPerDegreeAxis1 25600.0

#define AXIS1_DRIVER_MODEL TMC2130_QUIET_LOWPWR #define AXIS1_MICROSTEPS 64 #define AXIS1_MICROSTEPS_GOTO 64

// Axis2 is for Dec/Alt // calculated as : stepper_steps* micro_steps* gear_reduction1* gear_reduction2/360 // EQ5 : 400* 64* 2.5* 144/360 = 25600.0 #define StepsPerDegreeAxis2 25600.0

#define AXIS2_DRIVER_MODEL TMC2130_QUIET_LOWPWR #define AXIS2_MICROSTEPS 64 #define AXIS2_MICROSTEPS_GOTO 64

// PEC, number of steps for a complete worm rotation (in RA), // (StepsPerDegreeAxis1360)/gear_reduction2. // EQ5 : 25600.0 360/144 = 640000 #define StepsPerWormRotationAxis1 64000L

#define MaxRate 24 #define STEP_WAVE_FORM PULSE

#define RETICULE_LED_PINS 128

OnStep 3.16 Config for TMC2130 drivers is here (Vref=2.4V)

NOTE

• Polar Scope Iluminátor LED serial connected with 1kΩ rezistor. In STM32 board plug to MULTI socket 3V3 pin and reticle pin.
• FreeCAD sources on Github

UPDATE

• 2020-02-23 Add Config.h for OnStep 3.16 and Pulley_GT2-40v2.stl
• 2020-10-09 New red edition add RA/DE belt gear box cover and more improved
• 2020-12-12 Add GX16-4 ports version, PCB is on EasyEDA

Another recommended link:

• 3D printed - Small Travel EQ telescope mount
• OnStep for GS-280 (old GSO) EQ mount
• OnStep for SEBEN EQ3 mount
• My all desing for Astronomy telescope

Category: Other