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Hi Ken,
Their system as described uses a separate aligning scope and camera to that of the main scope
If this second scope is not coaxial with the main image scope all that means is that their aligning system is now polar aligned but the main system is not necessarily polar aligned !
The number of ways that it could be misaligned is quite a few !
But Differential flexure being an awkward one without an easily computed solution since it varies across the sky.
Add in some camera rotation and different mechanical/optical centres of the two telescopes into the equation and you have a mess.
Its no big deal but it involves more hardware and more alignment issues
But that is where Tpoint does its magic - it corrects in software almost everything else left that you couldnt quite achieve in hardware - except for freeplay/backlash in cheaper mount designs and PE (which is corrected with other software and/or mount integrated firmware)
And this is all done with the main scope and main camera (no need for duplication)
So today there are simply better tools available than existed for amateurs at the time they wrote that paper, that not only do the job much better - ie into the very low arcseconds instead of their claimed 2 arc minutes, but doesn't require a separate system and other hardware and the resultant differential flexure problems that most dual telescope systems will suffer from.
The moderm alternative also means that Tpoint is correcting for atmospheric refraction when pointing and other software such as ProTrack can actually make all the same Tpoint calculated corrections in real time during actual tracking, you can be relatively certain of excellent tracking right across the sky
Add in some regular guiding and of course your set !
Of course if this was really cheaply integrated into a telescope and or mount at the point of manufacture (say less than $100 which the Chinese could potentially do), I can still see that it might have some benefit for novices to get them started and remove some of the initial pain of polar alignment.
But 2 arc minutes of accuracy and another 1-2 arc minutes of atmospheric refraction and maybe some more in all the rest of a typical amateur system (flexure, backlash, mechanical errors, PE, loose fittings, sleeved nose adapters instead of threaded adapters, balance problems etc) suddenly we're looking at maybe 4++ arc minutes of error in Polar Alignment depending on where you end up pointing to after the initial alignment
But maybe the novice should just start with an Alt/Az mount and use 3 star alignment and then once they have the determination and understanding move up to an equatorial mount !
Its still interesting, but in many ways we have everything they proposed embedded within some of the more modern software - but we still dont have an automated mount adjustment system for EQ style mounts to set Alt/Az - but that would need two more drives/controllers on top of RA/Dec !
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