Tiny Clanger

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.

Have you clicked on 'how to use' at the top and followed the tour ?

OK, so cross that possibility off the list. You tried various eyepieces, and it showed in all of them. Could you try removing the diagonal and seeing if a straight through view still shows the problem ? The only other kit related (rather than seeing related) possibility I can think of is something inside the 'scope protruding into the optical path and causing diffraction (similar to the spikes caused by the secondary supports in a Newtonian)

Timely ! Not sure if it's a good thing if the answer is your eye or not ... it would absolve the new 'scope tho' !

I wonder if what you are seeing is astigmatism in your eye showing up in the Starfield, but not in your 'toy' refractor ? As I understand it (i.e. not very much) any astigmatism your eye may have will show more with a setup's greater exit pupil. If the old 'toy' 'scope has a higher f number vs the Starfield, perhaps the smaller exit pupil it gives allowed you to see pinpoint stars ... it could also be the reason you never saw the problem in a mak.

https://astrosolar.com/en/information/how-to/how-to-make-your-own-objective-solar-filter-for-your-camera-or-telescope/

OK, how about post-it notes (accidental discovery of weak re-positionable adhesive by 3M researcher trying to formulate a strong glue), umbrellas (originating as parasols to create shade) and that famous pill, intended for blood pressure lowering and anti-angina medication use, Viagra ?

With a 32mm plossl in your heritage 130 (assuming the plossl has a 50 degree FOV) the circle you see in the sky is about 2.5 degrees in diameter. That star Hamal in josefk's helpful Stellarium screen shot is a shade over 3 degrees from the comet tonight, so find Hamal with the 32mm, shift your dob so Hamal is on the edge of the view, nudge the 'scope a bit further and you should see a fuzzy thing ... centre the fuzzy thing then try some higher powered eyepieces. The main problem (apart from clouds !) you need to consider is that the view in your dob is upside down, so rather than putting Hamal at the left edge of your eyepiece, (around 10 o'clock if you think of directions that way) you want to shift the 'scope so Hamal is between 3 and 4 o'clock.

I had a different experience a couple of months ago: bashed my SS III on a door jamb carrying a setup through, the finder fell to the floor. What actually broke was the tiny screws holding the skywatcher shoe to the rubbish metal of the skywatcher - they ripped out of their holes. The Baader not only survived the bash and the fall onto a hard floor completely unscathed, but when I got new screws and re-installed the finder shoe, the SS III hardly needed any collimation.

Not being sure what mount that is, I did a search and FLO came on top, there in the page for the current version is "Frequently bought with this product: Sky-Watcher L-Bracket Dovetail" which suggests you will be fine , as does the FLO ad for the bracket which states : "The Sky-Watcher L-Bracket dovetail is a useful accessory for mounting telescopes, spotting-scopes and binoculars to mounts such as the Vixen Mini Porta and Porta II, Sky-Watcher AZ-4, Supatrak and AZ Synscan Goto and Celestron SLT and SE series mounts. Capable of securely mounting up to a 100mm aperture (4 inch) telescope or 80mm (3.2 inch) binoculars." Also this handbook (possibly for a different model ?) suggests some of these come (or came) with the bracket included https://www.manualslib.com/manual/1962294/Sky-Watcher-Star-Discovery-2i.html?page=8#manual To fix a 127 mak securely and retain the ability to fine tune balance I'd not use the single camera type screw though, I use one of these https://www.firstlightoptics.com/dovetails-saddles-clamps/baader-vixen-style-dovetail-clamp.html it has a threaded hole in the centre which matches the camera screw.

I've used a skywatcher 'L' bracket to mount my similarly 'wrong way round' 127 mak on my AZ5, it works fine, but that's on a substantial lump of a mount and a decently heavy tripod. The alternative with an AZ5 is to mount the mak effectively backwards, and with the AZ5 arm vertical, which limits the alt the 'scope can view, unless you remove the slo mo cable to let the diagonal pass it ... I don't know if that specific mount (or tripod) that the OP has could cope physically with the OTA on the bracket, and if the slightly outward displaced weight would cause balance or motor problems, (best keep the OTA as close to the mount's clamp as possible to avoid stress ) but as far as aim is concerned surely it will make no difference ? I've used a Rigel Quickfinder on my mak, the stick on bases work well.

30 posts ? Has it been changed from this ?

https://www.gov.uk/goods-sent-from-abroad/tax-and-duty Anything costing over £135 (that amount includes the delivery charge) attracts import tax, and the carrier makes a handling charge to cover their work collecting the tax on behalf of HMRC , it was around £10 on average last time I checked (over a year ago) and varied quite a bit between carriers, Royal Mail were £8, one of the cheaper options. You start your calculations with the VAT-less price plus P&P you are charged by the retailer, add whatever customs duty % are due, take that total to calculate the 20% UK VAT, then add the handling charge.

"Time is an illusion. Lunchtime doubly so."

This is a leap year, perhaps the device failed to cope with a 29th Feb. ?

And 'Hoover', 'Biro', 'Sandwich', 'Wellington', 'Shrapnel', 'Algorithm', Diesel' and of course 'Cardigan' 🙄

I'd love to know if the reason so many on CN spell Baader 'Badder' is that they just don't hear the long 'a' in their heads when they read the name.

If the focuser of your 127 annoys you as much as mine did, a relatively cheap way to get fine focus at the same time as buying a new diagonal is to get one of these : https://www.firstlightoptics.com/diagonals/baader-t-2-90-prism-star-diagonal-with-focusing-eyepiece-holder-125-nosepiece.html I find it works well .

@Wanderers , here's why you can't see it !

⬆️ What he said. Fine with a nice, short tubed 127 mak though !

He is, however his career as a popular entertainer with an apparently unblemished character lasted for 60 years and got him an OBE before he was arrested in 2013 for offences in the 1960s to 80s. I'm sure he would have passed many clubs 'is he a good chap?' assessments through all those six decades.

The problem is, who vets the committee ? Are they all DBS checked ? No-one, and I mean absolutely no-one, can spot a child abuser after a few hours of sitting in the same room. The regulations are as they are precisely because of what has gone on in far too many volunteer run sports clubs etc.

I doubt many astronomy societies would accept any under 16's attendance without an accompanying parent, the safeguarding regulations, and requirement for DBS checks of volunteers working with children, or vulnerable adults, are rightly quite tough.

It's not just me then ! I'd read nothing but very happy reports of the things until now. I really wanted to like it, but it just didn't fulfil its promise.

Exact same tripod - took the Castor off, swapped in the Sightron under the 102mm, tested it, didn't quite believe what I saw, restored the Castor to the tripod, checked it, swapped to the Sightron again, faffed with the arm's angle, tried the az slo mo on the far side, tried every variation I could think of, was unable to find one where the vibrations using the Sightron were not far longer lived than with the Castor, gave up. On a different tripod took the AZ5 off, swapped in the Sightron under the 127 mak. , again the vibrations took longer to settle with the Sightron than with the AZ5, and the az control was again in the way and could not be used with a cable. Not what I expected from such an expensive mount . The actual slo mo knobs are plastic, needlessly thicker than the ones that came with my AZ5, and held on by a single, finger tightened, white plastic topped screw. I tried swapping to the SW ones to see if I could gain a little extra alt clearance and was struck by how secure the SW ones were in comparison, being held on with two grub screws tightened by allen key. It didn't help using the slimmer SW knob, or the SW slo mo cables (no slo mo cables are included with the Sightron) . The mount itself is really nicely made, it has a quality feel, the slo mo movements are smooth, the movement when you loosen the clutch is lovely, it looks the part. I suspect it would be fine with an 80mm or smaller short 'frac, the smaller diameter tube might not be fouled as much by the location of the az slo mo, but it certainly didn't work for what I wanted it for.