pregulla

If you are able to focus on the Moon than it's not a focusing issue. Sounds like either bad seeing, or you didn't let your dob enough time to cool down, or you observe over surfaces that radiate heat, like concrete or roof tops, or combination of these factors.

Where are you observing from? From a dark site there are a lot of various targets for 8" Dob. From a city clusters are the main targets. This should give you an idea: https://www.nexstarsite.com/OddsNEnds/MessierDifficultyRatings.htm

I bought mine from AliExpress for $0.6. It has a hard cup. It doesn't "seal" perfectly but it also doesn't press against the eye. At a dark site it works fine for me. I have been using it for over 6 months and each session I keep switching it from one eye to another and it holds well and doesn't need replacement.

https://www.cloudynights.com/topic/655490-2019-nebula-filters-buyers-guide/ To be honest I don't really know where Don takes the data from. But judging from the reports of it being very close in performance to UltraBlock (which is about 30nm too) that sounds right.

I would expect some difference between the two. Optolong filters (and probably Svbony) are about 50nm wide. SW is closer to 30nm and there are some reports of it being roughly same performance as Ultrablock.

The drawback is it's size and weight, at least for me. For example ES82 11mm is 272g, ES82 24mm + 2" Focal Extender is 704g+655g. That was the reason I decided against getting 2" one, even though the price was really tempting - $80 shipped.

I have owned the 10x50. They were quite good for the price but I have replaced them with Bushnell Legacy for better eye relief, glass and coatings. I certainly wouldn't call either 10x50 lightweight or compact. They are pretty large and heavy. For astronomy I prefer 10x50, for all rounder 8x40 will probably be a good compromise. I would recommend getting Bushnell Legacy from Amazon.com. They are well worth the extra price imo.

Is it possible that it has a two-part cap and you are only removing the inner part?

It's a F/5 scope which is pretty fast, so Hyperions won't perform best at the edge of the field, but it's probably something else that degrades the view. What are you trying to look at and what exactly do you mean by "messy view"? Have you collimated your telescope? Did you let it to cool down? Was the seeing bad? Were you observing over roof tops or other objects that may dissipate heat and degrade the view?

Telrad wouldn't supersede it, not on a large reflector. They complement each other. A magnifying finder allows you to see things that you don't see naked eye. It gives you more pointers for star-hopping and wider field than lowest power eyepiece and allows to point exactly at objects you wouldn't be able to with just RDF/Telrad/Rigel. I use RDF + RACI finder and they work well together. I have also used straight through finder but find it less convenient ergonomically.

Bortle 8 is pretty bad. Stuff doesn't look like it's pictures. M81/82 might not be visible at all. Clusters should be an easier target. If you can catch Orion nebula it is an easy target, you can point right at it. I use SkySafari on my phone. You need to adjust settings so the stars you see in the eyepiece roghly match what you see in the app. Calculate the TFoV of your eyepiece and zoom in in the app. Find a path to your object using recognizable patterns. Baby steps, make sure you are certain where you are after each step. You may need to try multiple times or try different "routes". It takes practice, but it gets easier over time. Even if you can't see the target, you still gain experience.

If I was buying complementary scope I would get a fast refractor for low power wide field views. I think even achromat would do, since it is mostly higher powers where CA becomes a problem. Probably something around 100mm f/6 with 2" focuser.

I think these won't perform well at F/5. The 58 degree one is probably the safest bet. As AFoV gets wider it gets harder to make well corrected eyepiece. I would look for used ES68 16mm. 16mm Nirvana will probably perform good enough too, likely not as well corrected as ES68 but wider field. As for mobility, I just went to a dark site and I wanted to compare my 12" that I recently got to my 8". So I took them both + observing chair, eyepiece case and some camping gear in Skoda Fabia, which is a small car. SW Collapsible 8" tube fits standing on the front seat and the base fits into the trunk. The 12" fits on the back seats. When observing from home I just take 8" out in one piece.

You can take photos of the Moon. The planets are doable with a dob as well I think. With Newtonian on EQ mount you are buying yourself troubles for visual from the start. Focuser position changes as you rotate the scope and will eventually end up where you can't look into the eyepiece and have to rotate the tube.

Usually kits are poor value. You end up paying for stuff you don't really need. The one you linked I would certainly skip. I would rather buy 32mm plossl, 8-24 Celestron zoom and 2x barlow. I think dob will give you best views for your money. Newtonian on equatorial mount is inconvenient for visual observing. Larger apperture will show more on Moon/planets/DSOs.

I don't know, but I would guess they use different lenses. TV claims they are parfocal, from the pictures it looks like the nose-piece is the same length in both. When using the same lens for higher magnification it needs to be moved further in, so the nose-piece would be longer if 3x was the same as 2x. Stronger negative lens would make the cone steeper and only extend the distance from the lens to the eyepiece. Based on their pictures only that what seems to be happening. Full disclosure: I am not an expert and it's just a speculation.

Not the prettiest here, but gets the job done for me in the field