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Old 08-05-2019, 08:32 PM
Averton (P and C)
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Averton is offline
Join Date: Mar 2019
Location: Melbourne
Posts: 59
Hi Bojan & Chris,

Thanks for your comments & suggestions as they are greatly appreciated. We have learnt a great deal researching the items that you have suggested. "Why not use OnStep?" is an excellent question. There are a few reasons at this time.
  1. When we started this project we did not know as much about the various other options. Even at this time we have now only seen the online documentation of some of them and certainly not seen them in action so we are basically learning as we go along.
  2. We actually enjoy the making of things as well as astronomy. In fact, we enjoy the designing, making and programming of hardware. Also it is much easier to understand and modify code that you have written yourself than to work from other people's code. All a bit like exercise for the brain.
  3. We guess that if we are honest, like all engineers, there is a bit of the thought that you can design a better widget. This is probably not the case in this situation but there is still the fact that the design is for our own particular circumstance and constraints.
  4. This is the biggest reason. As you can see from the pictures, the hardware is completed and we are just tidying up the electronics. We have actually had the opportunity of using the mount with breadboarded electronics on a couple of occasions. It has certainly delivered on our original expectations, that being it is totally successful for observing over the one hour period without losing the subject from the FOV. However, as you pointed out from the very start, the design does have limitations and since using it we have had a small taste of the potential that tracking has for imaging. Testing thus far has shown that our current unit is good for low magnification and exposures up to 15 seconds, however, at magnifications greater than 200, the limit of reliable exposures is around 2 seconds. Basically all this means that we have already started to think about a better tracking design as a next project.
So the current plan is to accept this platform for what it is and enjoy using it and start thinking of an improved mount design. Our research thus far on OnStep has raised a couple of questions. As we use only Linux as our OS and Stellarium, the OnStep documentation is vague in this area. It talks about INDI drivers but then gives examples of its instruction set being Meade LX200 codes. This would seem to invalidate the need for an INDI driver when using Stellarium as Stellarium happily outputs LX200 codes to the /dev/ttyUSB0 port. We have put a serial port analyser on the codes and confirmed their validity and written a small amount of code to make Stellarium think it has a scope attached and this works. Another initial question is that the instructions for OnStep say that you should boot with the scope pointing to the SCP, which would seem to be less accurate than starting with the OTA level (which can be quite accurate) & facing north (not so accurate) but easier than the SCP.

Early stages of thinking for this next project so plenty of time to change things this time around.

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