Sonixx I m using a 178m in 2x2 bin on a 250mm guide scope. Guiding rate is 0,9x
Hi Stephan, what is the FPS that you get from that setup? When I tested the ASI178M with ASIAIR, I did managed to get 2 FPS, but couldn't get it to go faster than 2FPS. By comparison, the ASI290M can reach 5 FPS with 0.2 sec exposure.
Going over 1200x the mount will reboot on slew command with my power source. 13v 10A
That reboot just doesn't sound right -- did you check with xuranus (bjjeong@rainbow-robotics.com; B.J. Jeong's title is R&D Manager with both Rainbow Robotics and Rainbow Astro.) to see if that is normal?
FWIW, the specs for the RST-300 here shows that with a 12VDC supply, the mount can slew at 1000x sidereal, and 16VDC supply can slew at 1200x. (The RST-135 slews at 1500x with no problem.)
https://www.deepspaceproducts.com/product/rainbow-astro-rst-300-weightless-mount
My Voltage arriving at the RST while tracking is 12,4V and 12,1v while slewing.
This could be part of the problem.
What AWG wire did you use to power the mount (since a good 10A power supply should not droop much at all). The specs for the RST-300 claims that tracking consumes 0.4A and slewing consumes 4A. That means that there is a delta V of 0.3V (sorry, I use dot for the decimal place instead of commas used by Europeans :-) for a delta i of 3.6A, implying your cable resistance is a whopping 0.8 ohms. (0.4 ohms per wire of the pair of wires).
18 AWG stranded copper has about 23 milliohms per meter, so the 400 milliohm implies your wire is 17m long(!!!!) or your wire is too thin, or it is not true copper. (If you really have a 17m long cable, it is best to insert a DC/DC boost converter near to the mount.)
So, I would recommend getting this ohmic drop down first.
There are many wires at Amazon that don't have copper core, and also lie about their wire gauge. I have found this one to be good quality and has silicone insulation that does not become stiff when it is below freezing (they claim -60ºC, but I don't go out even at -10ºC :-):
https://www.amazon.com/gp/product/B0785FJNBJ
It is not cheap, probably because of the silicone insulation.
You might try the above wire, or some other real copper wire with at least 18 AWG to see if you can get the voltage drop at 4A to be less than what you are seeing. The one above appears to be tin-coated copper core.
BTW, the RST-135 tracks at 0.2A and max slew (at 1600x, 16 VDC) at 2A.
Another by the way, the AM5 appears to use the same Model 17 Harmonic Drive gear that is used in the RST-135.
https://www.harmonicdrive.net/products/gear-units/simplicity-gear-units/shd-2sh/shd-17-100-2sh
Your RST-300 probably uses this gear:
https://www.harmonicdrive.net/products/gear-units/gear-units/csg-2uh/csg-25-100-2uh
Chen