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I have an EQ5 telescope mount which i use for astrophotography. I have modified it with a motorised RA axis using a bipolar stepper motor - my thread for the build is here .
I want to expand the mount's tracking ability by motorising the DEC axis and using a guide scope/camera. I generally use the mount in fairly remote locations so would like to use a raspberry Pi for portability.
I understand that I'll need to use a Raspberry Pi Camera Module for the guide camera.
The capability I want is:
1. guide the mount along RA and DEC axes using a guide star as feedback
2. track the mount using the RA axis only, and if possible continuously take 20-30 second exposures on the guide camera (this functionality is optional, but would assist in polar alignment of the mount)
I don't want any GOTO capability. I am very new to RPi and need some help:
- do I need to write code for this, or is there existing programming available for what I want to do?
- is it possible to avoid the use of screens (in the field)? My preferred option would be to flick a switch to start and stop the guiding, with another switch for alignment mode (or something simple like this).
- do I need to use any particular stepper motors/drivers for raspberry Pi? I'm using a bipolar stepper motor running quarter steps, with an A4988 stepper driver
- is the RPi 3 Model B+ the unit I should buy?
I've picked up a second hand Lightrack II recently, so was keen to test it. My plan was to use the guiding assistant in PHD to get a graph of the tracking performance, but initially the mount wouldn't move. After a search, I had to modify the guiding cable that came with the mount, as it was wired up 'the other way' to the one required for QHY5L. After that it calibrated fine and could run the test. Below is a 22min graph of the unguided performance, while it's not within the 2" peak-to-peak quoted, it's still pretty good.
Next I've tried it with a canon 300mm lens (unguided again), the picture is a crop of a 10min exposure, slightly eggy, but again pretty happy with that.
I've set my scope up on it's pier in my ROR observatory, done a few drift aligns and started to take some images.
I've noticed a 'quite' regular dip in my DEC line on several nights.
Would anyone be able to have a quick scan of my log and offer any insight?
Could it be backlash? Could it be something with each rotation of the gears? Faulty tooth?
It is quite regular, although not always, and always in the same direction.
It doesn't seem to be adversely affecting imaging yet, but I've not tried anything too taxing.