Icosahedron

Additional information: Telescope: 80mm f10 achromat Barlowed to f22.5 Spectroscope: 2 x 900mm focal length achromats and 1800lpmm(30 x 30mm) grating Camera: 2088 pixel(14 x 14µm) CCD line sensor with 16-bit imaging signal processor Dimensions: 155 x 30 x 14cm Weight: 11kg

Spent a frustrating afternoon yesterday chasing sunlight here in the South East. One of my USB to Cat5 converters stopped working the day before resulting in a rather taut USB cable out the back door. No way of observing and making manual adjustments as the instrument was designed purely for remote adjustment. Unable to remove dust from the slit and discovering that I didn't allow for long enough camera exposure time. Worst problem was the clouds scuppering my attempts to find spectral lines with an instrument that is not calibrated. By a miracle the sky cleared long enough to make an attempt. A long list of problems to attend to but in principle it works! Brief description of spectroheliograph: Arduino DUE bit-banging a linear CCD sensor, positioning the optical components and handling data communication. Ordered a Teensy 4.1 last night. Did not have time to take photo's, that will come later.

I auto formatted your code and spotted a superfluous semicolon in the summing loop.

These do not require lubrication.

Sounds like stepper motor resonance during acceleration and deceleration to me. Apart from ensuring that the supply power is adequate there isn't an easy solution if it is the case.

Post deleted.

Looks like pin 7 on the motherboard is connected to the microcontroller via L7 and pins 6 and 8 to ground. Pins 7 and 8 on the EQMOD cable supply power.

This is more likely the problem.

Definitely a split ring equatorial mount with GOTO capability. Quite a coincidence as I've just started modifying my version of one this week, abandoned years ago as result of LP where I live. I now need something for my latest project and have decided against getting an EQ6. I don't see why a friction drive is in any way inaccurate. I regard it as gears with an infinite number of teeth. This does make it difficult to determine the exact ratios, but that is easily sorted with firmware. Unlike gears, worms and belts there is nothing to introduce periodic errors unless something is not round or centred, also easily sorted. IMO, if properly built it can be the DIY'ers 10 micron drive!

Could you please repost how you’re going to extract 4 bits of information from the symmetrical 3 track Gray encoder disc, I’m intrigued. The information you provided on this in 2012 doesn’t seem to be available anymore. Thank you.

Here is another crowd working on this. They report some success with chloroform and two matchsticks I suppose .

This is not something I'll ever attempt. I've read the first few pages of this thread and hope someone suggested later on to gently grind the sensor window off with fine grit and a little water on a flat piece of glass. Safe and easy.