Re: G11 Dual Axis & G8 Single Axis Configration #configuration

"Guilherme Vênere

My G8 runs with direct drive steppers and since I bought my Onstep kit with the steppers and brackets ready to install on the G8 I never cared about trying a reduction before.

But as George said the resolution in this case is very close to be a bother especially for astrophotography. I had many issues with this mount before (not related to OnStep) so only now i'm starting to check how this low resolution could affect my images, but it does seem to have an effect.

If you're starting from scratch i'd recommend looking at using reduction as suggested. 

Btw my imaging setup is a 102 F7 scope with an ASI1600 which gives me close to 1.1" per pixel so the resolution above is very close to my limit.


On Tue, May 4, 2021 at 3:33 PM George Cushing <stm32bluepill@...> wrote:
Yes, 1/4 looks reasonable. But the Losmandy SAIA steppers are not 400 steps. I think they are 24 step, 15° angle and the gear head reduction is 120:1. They were made in India.

Then there's the power issue, 83 Ohms means what, 150mA? 

Direct drive with 400 0.9° step angle and 64 µsteps may get you 0.91 arc-seconds a second resolution. But the same motor with a 3:1 GR1 and 32 µstep is 0.39 arc-seconds a second resolution. I'd work on getting some belt and pulley set up figured out. 

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