Gina

Don't know when I shall be able to check this outdoors, the weather forecast is for solid cloud for the foreseeable future Misty too! I now have just two stepper motors to control - focus and lens cover and I may be able to put both A4988 driver modules on the RPi HAT. The whole casing is in for a re-design now and this includes the lens cover drive arrangements. I'm expecting to reduce the size of the casing from the last design. More thinking needed

Focus motor with bracket added.

Photo of camera and lens with focus gear.

Stepper motor pinion. This gives about 2:1 reduction ratio.

Focus gear - a push fit on the barrel of the lens.

Test run completed using SharpCap (haven't got the RPi set up). Here is a photo of the rig and a screenshot from SharpCap of the image. The 1mm offset was too much so I turned the plastic part on the camera. I estimate the required offset is around 0.5mm.

First of all I'm printing an adapter to connect the camera to the CS/C adapter. This includes a 1mm offset which I think is about right. I can run a test to see and adjust the design if wrong.

Been looking into the ASC casing but there are problems due to the lens adjustments for focussing and alignment. In fact I definitely don't like my present design for lens control and have decided I need to find a better solution. The present arrangement is bulky, complicated and may be difficult to operate

The main problem with using the threaded C mounting as a helical focuser is the slop in the thread so I'm now wondering if spring loading the thread would cure that problem. I think it likely that if I can find a way to keep the lens straight while focussing, there will be no need to adjust the alignment. There is still an offset needed due to the imaging sensor being offset from sensor in the camera. The offset is only around a mm but with a 5mm sensor height, this is significant in getting full coverage.

I really don't like the three stepper motor focussing and alignment system even if I have almost completed it!! As I posted above it's causing problems with the casing, it takes up a lot of room and will probably be pretty awkward to operate. I think that's why I haven't felt like doing any more work on the ASC. I have now decided that I need to find an alternative solution - the present arrangement is not practical.

The MLX90614 IR sky temperature sensor looks useful for detecting cloud or clear sky

The electronics for the weather station will be in two groups - Arduino Nano + RPi at mast head and Arduino Uno + RPi in the scope room of the observatory. The wind instruments feed the Arduino at the mast head. Outdoor temperature and humidity will read by a DHT22 in a small Stevenson Screen attached to the north side of the observatory and fed to the main Arduino Uno. Finally the rain gauge I'm thinking I shall attach to the mast just above the roof of the obsy with Hall sensor and fed to the inside Arduino Uno. I may add a light level sensor too.

I shall need to give some thought about how to take the weather station data into the desktop computer, process it and send to the wall mounted gauges and web site etc. I could probably do this with INDI as I do for the astro imaging systems including ASC but there may be an easier way. It's beginning to get rather complicated for my poor old brain

Having completed the construction of the arm and casing etc. for my weather station wind instruments, I'm now coming back to the ASC as the casing will contain the Raspberry Pi that will run the weather station wind sensors. May be the same RPi as used for the ASC but I have yet to confirm that. I am having a problem with the design of the ASC casing due to the way the lens can move about with the alignment system.

Bottom cover plate installed.

Printing the bottom cover plate.

Yes, that's right That's exactly what I did in the past though I had only 16 possible values of the raw data.

The wind instruments on a pole outside. No bottom cover on the narrow part of the casing yet so the USB cable and Arduino Nano are hanging out. I've given the narrow parts a bit more overlap that I originally intended since the arm was longer than needed. I think I'll see about the bottom cover and ASC casing next.

This shows the errors in polar coordinates.

This screenshot shows the relevance of the errors concerned. One compass point (of 16) is shown by markers on the LHS. The errors are less than a quarter of a compass point ie. four times better (or more) than the standard for wind direction. There would seem to be little point in trying to reduce these errors.

Errors plotted on a graph/chart. Not exactly sinusoidal as shown more clearly in the two cycle plot but these are only small errors and the hardware settings are only accurate to a few degrees.

Changed calibration to 602 and ran test again. Errors :- -4, -4, 1, 5, 5, -5, -4, -4, -4

Yer 'tis Errors :- 1, 4, 6, 9, 10, 2, 4, 6, 2. Error range 1 to +10 = 9, a bit better than before.

Here's the raw data - one tenth of a degree resolution. Looks like 248 is the reference value. So formula required is 360+248-ii mod 360 = 608-ii mod 360. How strange, magnet seems to have gone back on the axle in almost the same orientation. I'll re-enable the calculation and do another test run.

That's cured it Now to do a test run...