The PE of SA is comparable to the PE of Vixen AP, which I own one. I found it not quite good enough to do 2-3 minutes of unguided exposure with a 180mm lens. So I suppose SA is similar. For things under 100mm, it works very well (under D800's resolution).
Other than the somewhat disappointing PE, the overall build quality of Vixen AP is excellent, and it's easy to use. It has a version without the Dec unit, so it works just like SA and other small trackers. Its tripod is more solid than what most people would get for a small tracker, but then course it's larger and heavier. Polar alignment is also easy.
I know you are sort of in the mode of "SA or nothing." This is just for your reference.
Thanks Wei-Hao. Honestly, if I could get something better for as cheap, I would. I'd get an AstroTrac, but it gets fairly pricey when you combine the necessary parts and all. I think Adorama has a full package for around $800.
I have been alternately intrigued and dismayed as well on this same score. Even a CG-4 with a clock drive and the shoestring astronomy auto guiding mod is ten times the mount. An AVX is just plain easy in comparison.
If price were not an object, I would agree with you. However price IS an object here. If you can point me to a used AVX for under $300, I'll go for it. ;P Well, actually, skip the AVX...if I had to pick between that and either a ZEQ25 or a Sirius, I'd take either one. The Sirius would really be it, as I already have an EQDIR cable and am already very familiar with EQMOD.
Orly, I looked around, and could not find a used SkyMemo. Looks like it might be the closest option to my price range. I found something on Amazon, the SkyMemo R, for just shy of a grand...and that looked like it was JUST the base head, no counterweight shaft or counterweights or anything like that. I did find an article where a guy tested the PE...he said it was 42 arcseconds P2P? That seems higher than either the SA or the AT. Has anyone else done any testing of that? The Tak EM-11 apparently has +/- 10" PE, so 20" P2P? Best I've seen, but it seems as though it's thousands of dollars, so well out of budget.
Steve, I have a quick question. You mention that using the polar scope can be difficult? I will be using the DEC bracket that comes with the Astro version of the SA. When you say you cannot use the standard illuminator, how and why is that? That seems like a bit of a problem.
At 14, 24, and 50mm, I'd be working within the PE of any one of these mounts, so I don't think that would be a problem. At 85mm image scale would be half the PE, so if the worm period is 10 minutes, that should get me more than enough time for 2-3 minute unguided exposures, and longer if I guide. I won't be using 180mm or 200mm for a while, just my thoughts on the upper limits of what I plan to use. If I have to guide to do that, then I guide. Not a big deal. I am not expecting this to be like an AP with absolute encoders or anything like that. I don't need high end, I need super light weight and cheap. I will be getting a 300-400mm scope at some point, but I'll use that on the Atlas, so I am not concerned about being able to use it on this small tracker. The key with this small tracker is cost and ultra portability, as a backup mount when I cannot otherwise image at a dark site, or simultaneous option for use alongside my main rig.
Edited by Jon Rista, 22 October 2015 - 10:21 AM.