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Originally Posted by ausastronomer
Rastis,
Dennis's comment about manually tracking with his SCT is not relevant IMO as a SCT fitted with motor drives is not optimised to be used by hand tracking. Actually some of them are down right impossible to use with the drives switched off.
Likewise I have used a 20"/f5 with a 2.54 metre focal length on numerous occasions at high power without issue. I think your making an assumption there Dennis without ever having tried to track with such a scope.
CS-John B
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This is good – we are getting to the nitty gritty of some useful stuff that hopefully Rastis will find useful. Your points are valid for optimized dobs and competent users but, you appear to have dismissed some of my comments on technical issues rather than the usability issue that I was attempting to illustrate. Therefore, I offer the following comments:
The equatorial mount used in my example was a Takahashi EM200 with the Declination clamp locked - all I had to do was nudge the RA. Despite the eyepiece being at the “wrong end” and the method of handling the OTA awkward compared to a dob, this was still easy and predictable due to the quality of the movement of the Tak mount. But, when compared to the ease of tracking, it still is a pain in the bum to me, a comment which may be relevant to the original querant.
Also, I have used Peter Robinsons fine (ex) 20” f5 Obsession so I am aware of how easy a good dob can be handled, so there is no assumption here – just a data point to alert the original querant that “try before you buy” would help avoid buyer’s remorse.
Astronomers tend to favour one or the other which just comes down to personal preferences, what works for them and what trade offs they are prepared to make.
Also, I suspect that Rastis would not be purchasing a 25” Obsession
Regards
Dennis