Recommendations: Edge HD or LX800?

[LukeJones]

I'm currently "getting ready" for an Edge HD, but am intrigued by the LX800, and am very interested in knowledgeable opinions. I think my situation would be very similar to many others.
For me it's all about astrophotography, and my history is the mistake of upgrading my 8" LX-90 to a an 8" LX-200 ACF, expecting "pin point stars". Several purchases later I finally found the WO PFLAT-4, a field flattener that does a reasonable job, but is big enough to make the use of an off-axis guiders impractical. Instead, I go with piggyback guiding, and constantly deal with differential flexure issues.

I've got my eyes on an 11" Edge HD with CGEM DX mount.
Expected benefits:
- Genuine flat field. I can put my flattener in the draw, and actually use my off-axis guider. I expect that guided tracking would be as good typical seeing - so that's the end of mount quality issues???
- Going price of $US3,700
- Focal length of 2800mm, which is great for everything but large nebulas - and I have my piggyback wide field refractor for that. Also have a farstar option. Perfect.
- From the 11" with central obstruction I'm effectively getting 87 sq. in. light gathering surface area.

Differences with a 12" LX800:
- Guiding built into the mount. Sounds great, as long as you don't end up fight differential flexure issues, and end up going for off-axis guiding instead. Early indications here are that everything will be much "tighter", right down to the OTA mirror - so perhaps flexure might not be an issue.
- Going price of $US9000
- The marketed "Ultimate Imaging Platform" appears to be just ACF. Bad memories for me. It would seem that imaging is useless unless you pay for a flattener. The big kicker here is that a flattener forces you to go to F5 from F8.
- Focal length of 2438mm, effectively reduced to 1523mm by compulsory flattener. Feels like a deal breaker to me.
- From the 12" with central obstruction I'm effectively getting 94 sq. in. light gathering surface area. No big difference. The larger obstruction halves the gain of 12" compared 11".

Conclusions: ???
- In truth I've always gone Meade, and I'm comfortable there. Looks, however, like I'd be paying over twice the price to go backwards in focal length by the time it's a genuine imaging platform.
- A built-in guider can't explain that price difference, and it seems like I'm risking differential flexure issues.
- Would the mounts be that different in quality, and would I see that difference with auto-guiding in average seeing conditions?
- Am I missing something else?

[Gem (Grant)]

I believe a CGEM DX is just a CGEM with thicker legs. Maybe you should be comparing the CGEM Pro to the Lx800?
You haven't said WHAT you want to image, so focal length issues are hard to comment on.
Somehow I don't think there will be many informed LX800 opinions for a while...

[LukeJones]

Excellent answer. Thanks.

Personally, I'm more keen on steady tracking than large weight carrying capacity.
I notice that your sig. states "Celestron CGEM". Any opinions about CGEM vs CGEM Pro tracking performance (at lower weight payloads)?

Whatever the raw tracking capability of an LX800 mount, I guess that the claim of +/- 1 arc sec tracking combined with built-in guiding is the standard for comparison (i.e. performance with guiding factored in).

As a family guy, my personal struggle is to make darn sure that, at the very least, a large hobby investment upgrade really delivers.
I sank many night hours years ago into developing my own telescope control guiding/image capture software, complete with flexure/drift compensation attempts. My fork/wedge Meade 8" LX-200 really delivers near the ecliptic (10-20 min subs with round stars), but really struggles with DEC closer to the north or south horizons.
Any "bonus answers" on how an equ. might cope much better than a fork/wedge closer to the horizons?

[Gem (Grant)]

Never used a CGEM Pro, and I am still saving to buy a CCD imager to use this my CGEM: so can't help too much. Next tax return time I will get a camera.
I am impressed with the quality of the CGEM and I bought it at the best time ($3500 for the CGEM 925). I deliberately bought the 9.25" to make sure it is running well within its weight range when I image down the track.
I am also running on a tight budget, so I was very careful in trying to work out what I wanted and how best to get there. I got the CGEM 925 since it was portable enough (I don't have a permanent site) but should deliver good performance. I didn't want to get more than one scope - I wanted a jack of all trades - visual observing, imaging, portability, etc...
So far I am very happy, although the normal Celestron SCT OTA take a long time to cool. The HD are much quicker than the standard OTA for cooling.