The AutoPA V2 upgrade is system that allows motorized polar alignment by turning the Azimuth and Altitude using two additional stepper motors.
AutoPA works using NINA's Three-Point Polar Alignment or Sharpcap Pro's Polar Alignment Routine to determine the error correction needed and the software handles automatically adjusting the mount to bring it in alignment with the pole.
Here are two video examples by Discord user @Elessar showing AutoPA achieving polar alignment using both Sharpcap 4.0 and N.I.N.A.:
Sharpcap 4.0 Example
Each axis can also be manually controlled via OATcontrol's minicontrol panel if you wish to make manual adjustments.
AutoPA has a range of +3/-15 deg altitude, depending on which track is used (short track is 6 deg less range than the long track). The +3 might also be limited by things like undermounted MKS cases, etc as they may collide with the bottom framing.
|Stepper Motor||NEMA17 0.9° or 1.8° (recommended) or 28BYJ-48||2|
|Stepper Driver||TMC2209 (recommended) or generic stepper driver||2|
|Shaft||d=5mm, length >= 75 mm (sold as 100mm, it is optional to cut to length)||1||https://www.amazon.com/s?k=uxcell+5mm+x+100mm+304+stainless+steel+solid+round+rod+for+diy+craft+-+5pcs&crid=RMOGMF2KRFB2&sprefix=%2Caps%2C128&ref=nb_sb_ss_recent_1_0_recent|
|Toothed Pulley||GT2, w=6mm, ID=5mm, 16T||2||https://www.aliexpress.com/item/32621920304.html|
|Idler Pulley||Toothless, w=10mm, ID=5mm, 20T equivalent||2||https://www.aliexpress.com/item/32817328238.html or https://www.amazon.com/dp/B07BPHRSN5?psc=1&ref=ppx_yo2ov_dt_b_product_details|
|Idler Pulley||Toothless, w=6mm, ID=5mm, 20T equivalent||2|
|Worm Screw + Gear||Brass, ID=5mm, 0.5mm module
|1 gear + 1 wheel (usually sold as a set)||https://www.amazon.ca/dp/B07G54YQL4
|Belt||GT2, w=6mm||~ 500mm|
|Belt tension spring||GT2||2||https://www.aliexpress.com/item/32650610030.html|
|M3 bolts||Various sizes (mostly 12mm)||~ 20|
|M4 bolts (if using 28BYJ steppers)||length=8mm||4|
|13_rear_AltAz_mount.stl||1 - Replaces default rear mount|
|Alt_Track_Short.stl||1 - for 50deg roll mount|
|AutoPA_mount_left_2020base.stl||1 - Replaces default left mount|
|AutoPA_mount_right_2020base.stl||1 - Replaces default right mount|
|u4_holder.stl||2 - From OAT Universal mount|
For help with assembly, you can view the complete model in your browser here: AutoPA 3D Model
Once assembled the system can be tested. Ensure the firmware is up to date with 1.9.32 or later.
Use the minicontrol panel in OATcontrol to manually control each axis to test up/down/left/right.
Refer to Electronics for directions for which position to use on the control board for each stepper motor.
While OAT with the autoPA Addon might work using cheap boost converters connected to 5V USB Powerbanks, the additional power required by the addtional two motors might cause issues when exceeding the specs. Reported behaviour is that OAT restarts when Alt/Az Motors are moved.
The AutoPA system works with NINA TPPA or Sharpcap Pro to measure the aligment error and automatically adjust altitude/azimuth.
Please make sure to have a look check
In NINA you will have to install the three point alignment plugin and activate logging in the settings.
See the Github README for directions to install and usage.
In addition to that please also check Software especially for Linux/Astroberry users check the sections Software > joystick_indi. You can use this script to manually move Az/Alt.
You can use OATControl to check if everything is wired up and working correctly, under mini-control you can manually move Az/Alt. See OATControl Point 8/9.