Hello everyone, I plan to build an electric focuser using a NEMA 17 stepper motor. I have some questions during the selection process and would like to ask for your advice:
-
What is a suitable holding torque for a focuser? Is around 40 N·cm sufficient, or is a higher recommended?
-
Is it necessary to choose a NEMA 17 with a gearbox, or can microstepping drive meet the accuracy requirements?
-
Is there a significant difference in focusing accuracy between a step angle of 1.8° and 0.9°?
-
How can I reduce the impact of vibration and resonance on image quality when operating at low speeds?
-
Are there any special recommendations regarding motor current and heat dissipation in astrophotography environments (low temperature, long-term operation)?
I welcome experienced builders to share their model selections and troubleshooting experiences. Thank you very much!