Astropi Customs is a GoTo telescope drive system for
new builds or replacement of bad factory controller boards
Software can be customised to a variety of mounts
Hardware and electronics components are readily available unlike factory parts
Astropi Customs drive system uses "Astropy" a Python library for Object Location Calculation
and can be used stand-alone or with Astroberry Astronomy Suite
Astropi Customs Drive is ST4 Guidable and Soft Pulse Guidable with
Astroberry Suite using the LX200GPS driver
See More About Astroberry Server Here
See More About Astropy Here
Astropi Customs troysworks at gethub
Using a Raspberry Pi for the object calculations and wifi app server
Using a Raspberry Pi Pico Microcontroller for the motor control and encoder counting
Serial UART communications between the RPI and Pico
Wifi App Interface for object look-ups or custom Ra Dec input
Wifi App Stepper motor system Overview DC motor system Overview
Mechanical Description
Stepper Motor Degrees Calculator Software Install and Configuration
http://astroberry:8008/ or http://yourhostname:8008/ on your Tablet, Laptop, or PC
Astropi Customs App details top to bottom:
1: Once Polar Aligned push Aligned button, Mode 1
Mode 2 = Tracking/Slewing, Mode 3 = Home Position
Tracking button toggles between Stopped to Slew/Tracking Mode 1 and 2 back to 1 Stopped
2: Your Site Latitude, Longitude, Above Sea level, Local Sidereal Hour
set in the configuration file "config.json"
3: Solar System Lookup and calculate button
4: NGC Lookup and calculate button
5: Messer Lookup and calculate button
6: Named Stars Lookup and calculate button
7: Custom Ra(H) Dec(D) Input and calculate button
8: Selected Object Information
9: Object Az(Deg), Alt(Deg)
10: Home Position goto button Mode 3, Mount Type EQ, Fork, Alt Az
North or South Hemisphere
11: Az/Ra deg/cnt, Alt/Dec deg/cnt, Mount Movement per count or step,
set in the configuration file
12: Calculated oscillator values
13: Drive Position +- counts/steps from polar aligned position
Error From setpoint and Adder count/step movement made from manual
direction buttons or guiding adjustments
Drive oscillator values
14: Manual Moves Buttons changes the object setpoint value , Deg-Movement small to large change
Warning Labels for "Below Horizon" and "Meridian Flip Soon"
Wifi connection http://astropi:8008/ on your wifi or ethernet cable
You must have internet access to use the App
Object positions are updated periodically
and need internet access to download IERS movement change tables
Astroberry Server
If using Astroberry Server, first install Astroberry Server on the RPI
then install Astropi Customs drive system
Stepper motor system Overview
eliminate unwanted movements
Electronics Parts:
1- Raspberry Pi model 3 or 4
1- Raspberry Pi Pico with GPIO header
1- Breadboard PCB 3.5"x2" or Solderless Breadboard
2- A4988 Stepper motor driver board
2- 100uF, 25v, Radial Electrolytic Capacitor
4- 1N34A Germanium Diodes for OR gate
Various 2.54mm header pins and breadboard jumper wires male and female
2- NEMA 17 Bipolar stepper motors 40x40x42mm is a 1 amp size,1.8 Degree with 1m Cable for 3D Printer
1- 5V DC Wall Power Adapter 2A, micro usb plug end to Raspberry Pi
1- 12V DC Wall Power Adapter 2A, 5.5mm x 2.5mm male plug and female jack for the case
1- SPDT 3 Pins 3 Position ON/Off/ON Black Rocker Toggle Switch
4- Momentary Mini Push Button Switch Normal Open
Current adjustment of the A4988 Stepper motor driver Go-by Here
1to3- The Joystick and the ST4 guiding cables plug into a RJ-11 6-wire female jack mounted on the case
3d stl files of the control box/case is available in the Download page
Other project boxes are available online and can be modified
Bench test App and stepper motor movement before
mounting in a case or on the mount
Mechanical:
Nice slip fit over 10mm shaft
Worm gear pressed over tubing
1: 1/4-20 wingnut, washer, clutch tension tube
2: 1/4-20 bolt welded to 1" shaft
3: 1" bore roller bearing
4: 96 tooth gear, worm gear, shaft and bearings
5: 2- 4" disks of cork gasket sheet, glued (contact cement) to gear and go-kart hub as clutch plates
6: 1" bore go-kart hub
7: 1" bore pillow block bearing
8: 2- 1" shaft collars welded to the OTA side frame/rings
Or 2- shaft collars welded to plates, bottom set screwed and the top is loose and greased
Shows the bearinged pivot rollers 3- used
See 12" dob pictures
Shows the output shaft and 8x10mm coupling to the worm gear shaft
8mm Bearings pressed/tapped into reducer box
Mechanical Parts:
Suggested parts list for 2 drives and Alt Az pivots
1- 8mm x 300mm shafting, cut 4- 65mm reducer boxes, 3- 31mm Az pivot bearings
2- 10mm x 200mm shafting, worm drive shafts
14- 8mm bore 608-2rs ball bearings, 8- reducer boxes, 6- Az pivot bearings
2- R16-2RS 1" bore ball bearing, worm drives
4- 10mm bore pillow block bearing, worm drives
2- 2GT 158 length 6mm width timing belts, reducer boxes
2- 2GT 220 length 6mm width timing belts, reducer boxes
2- 2GT Timing Pulley 20 teeth 8mm Bore, reducer boxes
2- 2GT Timing Pulley 20 teeth 5mm Bore, stepper motor
4- 2GT Timing Pulley 60 teeth 8mm Bore, reducer boxes
6- Shaft collar 1" bore, 1-1/2" OD, 5/8", Alt Az pivots
2- Go kart sprocket Hub, 1" bore, Alt Az clutches
2- 8mm to 10mm bore shaft coupling, reducer boxes to worm shaft
8- M6 Hanger Bolts, worm drive shaft bearings
4- M12 Hanger Bolts, Alt pivot pillow block bearings
3- 3" Swivel Caster Wheels with Safety Dual Locking
Stepper motors use m3x10 bolts and washers and box covers use #4x3/8" screws
3D STL files for gears and reducer boxes are on the Download page
Amazon and robotdigg.com has most of the parts
1" Shafting cut to +- 130mm and 80mm for Alt pivots, and 136mm Az pivot
Check your local scrap metal store before ordering shafting from others
Stepper Motor Degrees per step Calculator - Worm Gears
Worm Ring Teeth @ 1:1 Reducer to stepper ratio :1
Stepper 200 steps per revolution =
Deg/Full step - Use this number in the config file
Deg/Micro step - Tracking speed
CPS Tracking Oscillator 1/16 Micro Step - Calculated by the App
(Above 15 CPS is preferred and smoother)
Ring Teeth Pinon Teeth Reducer to stepper ratio :1
Stepper 200 steps per revolution =
Deg/Full step - Use this number in the config file
Deg/Micro step - Tracking speed
CPS Tracking Oscillator 1/16 Micro Step - Calculated by the App
(Above 15 CPS is preferred and smoother)
Software Install and Configuration:
Astroberry contains INDI driver server, KStars Graphical Views and telescope goto interface
Ekos Device Manager for Mounts, Cameras, Filter Wheels, CCD's, Guiding ect.
PHD2 Guiding
If using Astroberry Server, first install Astroberry Server on the RPI
then install Astropi Customs drive system
Astroberry Basic Setup:
Astroberry telescope driver for LX200GPS
Profile Editor for LX200GPS
Indi-KStars to Astropi Customs network socket for LX200GPS mimic
Use 127.0.1.1 and port 10760
For Stellarium thru INDI server add telescope add-on configure and connect with
these settings:
Use INDI and add a scope name
Use astroberry or your host name, port 7624, refresh devices
and select LX200 GPS as mount driver
For stand-alone installation Choose "Raspberry Pi OS with desktop"
Raspberry Pi OS Go-by Here
Follow default install and set the following:
Configure Wifi
Add Host name, as description of the telescope "astropidob12" for example
Enable SSH, Disable Serial Console, Enable Serial Port
Once raspbian OS is installed or your using Astroberry Server pre-installed
Install Astropi Customs from gethub.com Go-by Here
wget -O - https://raw.githubusercontent.com/troysworks/AstroPiCustoms/main/setup.sh | bash
The install adds a service to start on boot-up
You should be able to run the App as
http://yourhostname:8008/ on your Tablet, Laptop or PC
Raspberry Pi Pico examples are also Here
I'm using PyCharm IDE for development and debug and
Thonny IDE A MicroPython interface for the Raspberry Pi Pico
Save a Pico example as main.py on the Pico to auto start on power-up