Tiny Clanger

You need to remove the mirror cell from the tube to get to the clips which hold the mirror in the cell. If the clips are pressing on the mirror, the glass distorts, there needs to be a tiny gap between the mirror surface and the side of the clip that faces it. It sounds scary, but if you are very careful it's not hard to take the cell out (best mark the outside of the scope tube and the edge of the cell before you start with some masking tape or similar, to help get it lined up exactly the same way round when put back together to minimise any collimation loss) I've managed it with a 250 newt and I'm a weedy ham fisted fool. The usual advice is there should be a gap big enough to allow a sheet of paper between the glass and the clip.

Plenty to read here : https://stargazerslounge.com/forum/185-getting-started-with-observing/

Can't help you decide, but can point out a returned starfield with a reduced price available : https://www.firstlightoptics.com/offers/offer_starfield-102mm-f7-ed-doublet-refractor_431919.html

There are no simple answers to your question, if there were, there would only be one telescope available in that price bracket. As others have said, you need to slow down and do some research, otherwise you could make a very expensive mistake. You said you could carry a 10 to 12kg weight ... that's not much, and makes me wonder if you are either small or quite young ?

OK, so no limitations on storage or moving the kit apart from a weight limit. A biggish dobsonian (200mm aperture and manual, not a go-to with motors) will be well above 12kg , but if split into two parts (base and tube) to take it out you might manage. Check the weight of anything you consider, sturdy tripods and mounts are not light, neither are telescopes. As you are somewhere populous, there should be a club within reach where you can see some telescopes in use, that should be your next step.

For anyone to be able to give you a useful answer, you need to give far more detail. What you have asked is like someone going to a car forum and asking what is the best car to buy to be cheap to fuel, be a 4x4 to drive up rough mountain tracks, comfortable to carry a big family on a long drive on holiday, and do 200kph on a racetrack Is your home an apartment, a house, a house with a garage or other secure storage? Is the route from storage to where you will use the telescope level and clear, no steps, rough ground, narrow doors? What kind of weight of awkward shaped yet delicate equipment could you confidently carry from your storage to viewing place? Some setups in your price range are over 35kg. Do you have electrical power available at your viewing place ? Where you live do you have dark rural skies, city lights, or nearby bright lighting you have no control over ? Tall buildings or mountains or trees obstructing your view in some directions? Those factors can have an enormous impact on what you might be able to see, even with a great telescope. Where are you ? We don't even know what continent you are on, some makes of telescope which will be recommended may only be easily available in the UK, or EU, or USA ...

The 'UFO' was probably a very out of focus star, possibly the shape you saw was caused by your attempt at collimation. As bosun21 said, use just the correct extension tube for the diameter of eyepiece, also ensure the front section of the flextube dob is fully extended and locked in place. A poorly collimated laser in a stock skywatcher flextube focuser is a recipe for disaster - I know, I have a 250 flextube ! Using the provided extension, the laser (even after being collimated) moves as you touch the focuser, and tilts as you tighten the screws that hold it in place. This is a good explanation of the various ways to collimate https://garyseronik.com/collimation-tools-what-you-need-what-you-dont/ Gary Seronik also gives the clearest account of how to collimate I've ever come across https://garyseronik.com/a-beginners-guide-to-collimation/ I found the best method with a laser is this https://www.tomhole.com/wp-content/uploads/2020/12/blaser.pdf a particularly useful thing as it's easy to see the bottom of the barlow and the faceplate you add to it through the open section of the flextube.

You might be able to find either a window clamp or a hide clamp intended for birdwatchers etc spotting 'scopes that would suit whatever form the balcony rail or barrier takes ? That would remove the awkward tripod leg problem, and make them able to use a small 'frac . or binoculars. I'd want a secure tether on the instrument as well though, just in case ...

Best not treat this forum as just a marketplace, partly because that's precisely against the rules and the spirit of the place. Read this if you've not already done so: https://stargazerslounge.com/topic/105855-forum-code-of-conduct/#comment-1044622 (but note the requirements for seeing the buy/sell section are now 25 posts and a month's membership) and these https://stargazerslounge.com/topic/383673-important-change-to-buy-sell-access/#comment-4144265 https://stargazerslounge.com/topic/419332-buy-sell-safety-warning/#comment-4462445 Personally I'd not buy anything sight unseen from someone with little posting history, someone who offers no clue about how they may actually have used the kit they want to sell, has no apparent interest in being part of the community. Other red flags for me would be someone who does not show photos of the sale items, whose sale text is just the manufacturer's blurb copy/pasted with no hint of personal experience, or does not specify at least a county as their location while saying they are happy for collection. I've bought the majority of my kit from people on here, always paid by bank transfer to secure the item, even if I was collecting in person days later. I was confident to do that because the sellers were (are ! ) active members on here with a reliable history who were well known to me. My trust has not been betrayed, and I have some really nice kit I simply could not have afforded otherwise. Thank you all, you know who you are ! I've not sold as much, but again people have paid me by bank transfer (I don't, and won't, do paypal ) and if the item was posted I've PM'd the recipient a photo of the proof of posting you get at the P.O. as soon as I've sent it off. Even for small low value items items (sent non tracking) the free proof of posting receipt shows the address the package is being sent to as well as the date/time and how much postage was paid. ABS I keep an eye on, but to be honest unless something was very local so I could see it before paying cash, I'd not risk it. ENS Optical in Birmingham are dealers in second hand gear, I've no idea what their buying prices are like, their selling prices often appear rather close to the new price. I've not used them myself.

See also 'salute'.

'Salutation' is an English word meaning a greeting, we did not escape the Latin influence.

And so it begins ...

Just unscrew and remove it.

The link didn't work for me. I wonder if it is pointing to this though ?

I think OP has already told us what the 'scope is when they say, " I found this site, along with some delightful reviews of the Seben Big Boss 1400-150. Oh well, I guess it was free... " Amazon reckon : "Seben's Big Boss 1400-150 reflector telescope is, because of its perfect workmanship and enormous performance data, the unquestioned top telescope of Seben's astronomy series. Undreamed of possibilities become true for the ambitious user of Seben's Big Boss telescope because of its huge 150mm aperture and the tremendous focal length of 1400mm." https://www.amazon.co.uk/Seben-Boss-1400-150-Reflector-Telescope/dp/B00692THU2 It's a Bird Jones (or possibly Jones Bird ?) design, which the above ad avoids saying by using the term catadioptric.