Telescope Reviews: Upper End Mounts worth it Anymore

First, you have to define 'good tracking', and what that means to _you_. Allow me to illustrate with our own case(s) here.

Case 1, Williams 80 mounted on an HEQ5, using a 9x50 with starshoot autoguider to guide it. Camera is a Nikon D-50, which results in an imaging scale of 2.95 arcseconds per pixel. The guider has a resolution of 6.1 as/p. Tracking of +- 1 arcsecond is more than adaquate to produce very good images out of this system, and, the guider is quite capable of keeping our HEQ5 running at that kind of accuracy. So, I can see absolutely no reason to upgrade the mount underneath it, none at all.

Case 2, 8 inch SCT mounted on an EQ6-Pro, using an ST80 on the guide side, another starshoot autoguider in that one, and a canon 350 on the SCT, which runs mostly without any reducers. That imager runs about 0.66 arcseconds per pixel. To get good images out of this one, I need tracking far superior to the above kit, on the order of +-0.25 arcseconds. Again, the guider on this one is capable of producing that kind of accuracy, so, as above, no real point in upgrading the kit underneath it. But, I will also mention, the guider really does work on this kit. Again, that's why I bought it, to make corrections to the mount. It would be a waste of money buying guide kit if the mount doesn't need any corrections.

BUT, I'm happy with a system where the guider is providing inputs at a relatively high frequency. That's exactly why I bought it, to do just that. In all honesty, I dont look at guider output, I look at the final images on the imaging side. But, some folks are not going to be happy with a system that sends guider updates every 5 seconds (second harmonic of the first gear mesh). For those folks, then neither of our mounts will be considered 'good enough', and they'll have to upspend a bunch to get a mount that wont need such aggressive correction at the resolutions we use. That fine with me, its their perogative (and money).

More folks will be shooting at yet higher resolutions, swap out my 8 inch at 2000mm focal length, swap in something closer to 4000mm, and I dont know if my EQ6+guider will be quite as good underneath it anymore. With pixel resolutions on the order of 0.33 arcseconds, we'll need tracking accuracy at 0.1 arcsecond or better, and that's going to be a tall order for my kit. At that point, I'd have to do some tests with the PEC on board, and see if that can bring it into line with what I want/need, but, up to now I haven't had to experiment with that, altho it's in the plan for the not to distant future. In theory, properly trained for PEC, even my mounts _should_ be up to a job far more demanding than I'm putting on them today.