Firstable thanks, I will take those advices to my next posts, and for now:
I want my scope to be in my balcony, I want to see both deep sky objects and planets equally, I think Goto is better for me because I want a tracking system, and my budget is around 300-500 dollars
OK. Bear in mind that I am still relatively inexperienced, but I've been in your shoes just two months ago so here's the result of my "research"
1. For viewing from a balcony, where you have to clear obstacles like railings etc… tripod-mounted is better than a Dobsonian mount – which makes your scope sit very low. You lose something in stability though… so make a mental note that you need a good tripod and mount or observing will end in frustration (stability is key).
2. For an "all rounder" beginner scope, a Newton has many attractions. It's the cheapest inch-per-aperture design (aperture rules how much light you can gather = how faint the objects you can see + how detailed the view can get). 150/750 is what I also have, and it means that you have good light-gathering capabilities, a good field of view while retaining good magnification potential.
3. The downsides of a Newt are: it's bulky relative to a more compact Maksutov or Schmidt (but not very heavy). Ssince it will stay in one place most of the time, not much of an issue. A Newt also needs regular collimation by you. The first time can be tough, then it's a breeze. It's a consideration only if you're completely averse to doing technical work on your scope.
4. Note that you already have a few "trade offs" to consider. The bigger the aperture, the greater the capabilities of your scope, but the bigger and heavier it will be, and the sturdier, heavier and pricier the mount you need for it. (Dobs are a huge success because they are typically big newtonians – 8" and upwards – on very stable, basic mounts). 6" (150mm) was for long considered the "serious beginner scope". Another trade-off: the longer the focal length, the higher the inherent magnification but the smaller the field of view. 150/750 has wide field, good mag. 150/900 more mag and a slightly smaller field of view. There are terms like "fast" and "slow". These refer to the focal ratio of the scope (aperture:focal length). A 150/750 is "fast": less bulky but a little harder to collimate. 150/900 is a little "slower": a bit bulkier, but a little more forgiving. As a complete noob, I did well with my "fast" 150/750 Newt.
5. Whatever you do, avoid Bird-Jones telescopes like the Powerseeker 127EQ. Consult the spec sheet: if you see a long focal length (say 1000mm) for a tube that is physically shorter, it's not a true Newtonian and you should steer well clear. Also: if you buy a Newtonian make sure that is has a "parabolic" (as opposed to "spherical") primary mirror. That's one of the corners that must not be cut.
6. The mount. The fact that you want to "track" does not mean automatically that you need a GoTo. A manual equatorial mount does that equally well. Getting a manual mount might get you a better overall setup (tube and mount). But you have to "enjoy the chase" and sometimes it involves contortions around your scope. The learning curve is also a little steeper perhaps, though entirely feasible. If you'd rather go out, punch the coordinates and have the object in your eyepiece (well… that's the idea at least!) a GoTo is for you and there's no harm in that. Note: a big tube on a flimsy mount is a recipe for frustration. Whatever you buy, make sure that the mount has a payload that exceeds with a margin the tube you're buying for it… and ask around here for advice. I am afraid that I don't know the mounts in the kits you're suggesting, but the cavalry will be along soon.
After all the deliberation, I opted for a Celestron OMNIA 150 XLT: a good 150/750 Newtonian on a good beginner equatorial mount. Sky-Watcher has similar offerings for a little less IIRC. It's a little above your budget, but you might find something similar – or buy separately a good 150/750 Newtonian tube on a relatively sturdy EQ 3.2 or GC-4 mount. And given the current shortage – you might look in the classified for used scopes and get a very good combination.
But this is just one take… others will suggest other scopes. Each kind has its relative advantages and disadvantages. Before you buy, do some reading on that.
A resource I found super-useful: http://telescopicwatch.com
Edited by radiofm74, 03 March 2021 - 03:26 AM.