If I go for a Celestron 9.25” C91/4 SGT XLT, I’m looking at $1,874 and 62 pounds total net weight. This doesn’t break the budget and my wife will be no worse for the wear. However, if I change out the 24mm Panoptic for a 41mm Panoptic (since the 9.25” comes with a 25 mm Plossl instead of a 40mm Plossl), the cost of that lens is $200 more than the 24mm Panoptic (a 55mm TV Plossl would be about $65 less than the 24mm Panoptic). So far so good, I’m still below my total budget for the Celestron 8” Nexstar GPS XLT and accessories. But if you add a polar alignment tool, you’re pretty much back at the same price as the Celestron 8” Nexstar GPS XLT and accessories.
You do not need a polar alignment tool. Sighting Polaris through the mount hole works just fine.
Celestron 9.25” C91/4 SGT XLT vs. Celestron 8” Nexstar GPS XLT: From what I can tell, even though I’d be gaining 1.25” in aperture, I’d be giving up the following (based on the Celestron and Astronomics product descriptions, and ignoring the advantages of a german equatorial mount (the 9.25” SGT) vs. the cost of a wedge (8” Nexstar GPS) vs. Fastar capability (8” Nexstar GPS) since Astrophotography is not a major issue for me at this point):
o The GEM mount of the SGT XLT doesn’t appear to be of equal quality to the Nexstar GPS Alt/Az fork mount or the CGE mount - taking into account jrcrilly’s points.
Perhaps it's not of the same quality. But the quality is more than adequate.
o GPS (but could be added at extra cost), compass (which provides, I believe, auto north, so no need for polar alignment), altimeter, auto leveling, Permanent Periodic Error Compensation, adjustable backlash compensation, serial ports, separate CCD autoguider port, separate 12 Volt DC accessory power outlet.
And the net value of this in practice is... skipping the polar alignment. Which takes about 30 seconds (make sure mount is level, then sight Polaris through mount hole).
o Aluminum Tube vs. Carbon Fiber Tube (in Nexstar GPS)
o Does the SGT XLT cause cable wind around the mount when slewing (it looks like it would)? The Nexstar GPS doesn’t.
I doubt you would ever be able to tell if your Carbon Fiber tube was replaced by an Aluminum one. And no, the AS-GT does NOT cause cable wind, the mount is smart enough to go the long way to avoid that.
o Ease of setup / breakdown compared to the Nexstar GPS fork mount.
o Slightly greater portability (in terms of the size of the tube) with the Nexstar 8” GPS (although this may be a draw since the Nexstar GPS fork mount is so large and is not easily removable).
o Nexremote Telescope Control Software (not included in SGT XLT accessories list).
o AC adapter (included in Nexstar GPS accessories list) vs. car battery adapter (included in SGT XLT accessories list) is a wash.
Ease of setup if you are strong goes to the Nextstar GPS. But the difference is minor. (I say if you are strong, because the 45lb weight is a bit much for some of us with bad backs). The SGT breaks down in the OTA, the mount+tripod (one piece in practice) and the counterweights.
NexRemote I am unfamiliar with. What exactly does it do? Make sure it is something that you would miss before you assign it a value.
I am not trying to put down the Nextstar series, which is a great series. But if you get a Nexstar, the scope to get is the Nextstar 11! The other scopes in the series are simply way overpriced. Make no mistake, the difference between an 8" and a 9.25" is quite real.
And I AM trying to score a few points for the AS-GT series, which I think is an incredible bargain. I have one and two friends have one, and we all love the mounts (although there IS a learning curve). The truth is that after the feature comparison excitement, the following things matter most:
1) Quality of OTA
2) Stability of the mount
3) Accuracy of the GoTo system
Then the two concerns below are important *IF* they are outside acceptable limits:
4) Ease of setup
5) Ease of transport
The AS-GT is at a happy point where 4) and 5) are not real factors. I rejected the Nextstar (I only considered the 11) because I could not lift it due to a bad back, so for me 5) *was* a factor.
Anyway, good luck with whatever you decide!