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After reading and re-reading what you posted, my 2 cents: The Orion 80ED is more perfectly suited to your Porta II mount, and is less expensive. The AT102ED is starting to approach the limit of the Porta II mount, especially at higher magnifications. You might end up wanting to use a better tripod to make the AT102ED more steady on the Porta II (or maybe not; you may be fine with it... Do some searching/reading about the Porta II and you'll find lots of opinions). The AT102ED is certainly more capable. It has 38% more light gathering and more resolving capability due to the larger objective. It is not a night and day difference; the 80ED will still present a very enjoyable view, but looking closely it will be noticeable. For example, open clusters will show a few more faint stars with the 102ED, and as others said above, the moon and planets will show more detail. Your Zhumell Z8 will be a night and day difference on anything that fits in the field of view, and in that respect, either scope will be a great compliment to the larger scope. Either scope would be about the same time/trouble to set up in the backyard. The 80ED might be a little easier to carry out the door on the tripod/mount, "all in one trip," which is important to some folks. Either scope will give you very enjoyable wide field views. Finally, if wide field observing is your goal, don't forget you will need a good 2" star diagonal and 2" wide field low power eyepiece in order to get the best wide field views. Some of the 30-40mm 2" eyepieces are expensive and very heavy. The APM 30mm ultra flat is well-regarded, not quite as heavy, and a little more affordable.
One more thought: An even smaller scope than the Orion ED80, with a shorter focal length, something like the AT72ED II for example, would also be a lot of fun on the Porta II. It is back in the more perfect size range for the mount, with even wider possible views (although as the focal length of smaller scopes decreases, field curvature starts to make it more difficult to keep all the stars in focus and sharp out to the very edge of the field). And a smaller, shorter scope like this would be truly "grab and go" size, very different from the AT102ED. A better choice for daytime/terrestrial use too. So in your situation I might go for the AT102ED partly with that in mind (the idea of someday having the option of choosing between 2 more different big/small scopes for the same mount).
Edited by Passerine, 18 October 2020 - 01:34 PM.