starnet59 Replying to my own post, I had a very short window of clear skies tonight and I was able to do a first test with the EQ mode. It really works and I do recommend it highly, this and the plan mode is what the S50 should have been launched with more than a year ago.
First of all, an adjustable EQ wedge is nice to have but not really necessary, you can get away with a fixed wedge by adjusting the legs of your tripod. I do have the adjustable wedge but I tested with my 3D printed fixed wedge for those who do not have one, it really does work, so if you cannot afford or cannot find an adjustable one, there are workarounds.
There are two big benefits of EQ mode, much better stacking efficiency, expect 80%, not 50% from now on, and of course, no field rotation. This coupled with the plan mode makes building your own mosaics really easy now. I plan to stop using Alt/Az mode completely and switch to EQ mode entirely from now on.
There were some questions here about the need to see the North pole to do the polar alignment. You definitely do not need that, the alignment is not done on Polaris at all but on the zenith. When you start the polar alignment procedure the scope points straight up, takes an image, does plate solving and then tells you by how much to move the scope in Alt and Az directions to achieve polar alignment. You do that by adjusting your wedge, or if you only have a fixed one by rotating the tripod and adjusting the length of individual legs until you get within 0.5 degrees of polar alignment, which is more than good enough - this is very similar to the leveling process used in Solar mode. It's easy and it works, even with a fixed wedge. It also makes sense since you are very likely to have zenith visibility all the time, except for those unlucky users who live in high rises and only have sky visibility from balconies - in that case you most likely do not have zenith visibility at all. I would be curious to know if people in that situation are able to do polar alignment. But you definitely do not need to see Polaris at all to do polar alignment, which is great. You need to point your scope toward North at first, but the alignment requires zenith, not north pole visibility. Also, it would be nice to hear feedback from people in the southern hemisphere or very low latitudes.
Another thing I highly recommend is to install a compass and inclinometer app on your phone, there are plenty of free ones for Android and I assume the same is true for iPhones. You can get within a couple of degrees of correct polar alignment with these, even before starting your S50 and this makes achieving alignment much easier, both with adjustable and fixed wedges.
People have suggested (and I include myself in that group) that exposures longer than 30 seconds would make sense in EQ mode. I am not so sure now and while a nice to have new feature, I no longer consider it of high priority. The only benefit would be less memory usage when saving every raw frame, but I do not think your images would get better, even without the field rotation. With an uncooled sensor you would probably get more thermal noise that way and not gain anything in SnR. For now I plan to turn back saving every raw frame on, stay with 10 second exposures and empty the storage more often. I will experiment with 20 and 30 second exposures when I have more clear nights, which is not the case right now, I am back to cloudy nights for the foreseeable future.
All in all, I have to admit that ZWO has finally delivered something very useful, especially when coupled with the new planning mode. Which by the way, seems to have increased the start and stop limits for the night by 30 minutes or so, which is also very nice to see.
