Hi Frank,
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Originally Posted by telecasterguru
But this is version 2 so it must be better than version 1.
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yes it is a V2 version but what did they change and why was a V2 needed at all?
The main point for the V2 was the build in ST-4 Port as they realized that a autoguiding port IS NEEDED
and the system is useless without such a port because you need a way to correct the DEC axis, the Refraction, and align errors that the system is not aware of.
But what happens if you connect a autoguiding system to this port?
In my opinion the system is simply deactivated
when useing this autoguider connector. The
manufactor, no not meade, makes this clear!
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Important: TDM has a dead-time on auto-guider input following the end of the last auto-guider correction period for as long as 2 seconds avoiding excitation and resonance problems of two different control-loops.
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So if your autoguider sends impulses within a time period of 2 Seconds!, what is a very long time for a autoguiding system, the system is in dead-time waiting the autoguider stops working. I think this just happens after the exposure.
Other disadvantages, beside the price:
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Using TDM you need to accomplish very accurate polar alignment
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Without a polar scope
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There is no optical feedback from the certain part of the sky observed so your telescope needs to have a sturdy and rigid mount which is not cheap
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A autoguider do not have such limitation.
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This system is insensitive regarding flexure of mechanical parts and weak quality RA bearings.
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No problem if useing an off axis autoguider.
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TDM cannot follow objects in the sky having remarkable proper motions
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No problem with a autoguider at all.
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This version of TDM does not compensate air refraction
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Any autoguider will do this job.
CS
Rajiva