Ricochet

Which telescope exactly do you have and which screws have you taken out? Photos might help here. It sounds strange for the mirror cell to be fixed with nuts on the inside of the tube that you can't reach, after all someone in the factory had to put it together in the first place.

Given that you have several recent posts in the imaging section I assume you want the new mount for imaging purposes. The mount that is always recommended as a minimum for the smaller 130pds is the HEQ5, so I would be quite wary of putting a larger telescope on a smaller mount. If that is the mount that is needed, then by buying a cheaper mount you are not saving the difference between the two, but wasting the cost of the cheaper mount as it is likely that you will end up having to buy the more expensive mount in the future.

I think your individual eyepieces are safe as monoviewing is still superior for stars and DSOs where you want to keep brightness as high as possible (IMO). Also BVs tend to restrict you to narrow FoVs which you often don't want.

I think quite a few people do. I remember @Louis D has a pair of Celestron Regals but I think most people choose the Baader MKIII / IV. With my binoviewers the dioptre adjustment twists up and down and can't be locked so a zoom that I need to twist doesn't really appeal.

Dew forms on the corrector plate of a Mak and the lens of a refractor so you want it wrapped around the tube at the closest point to the lens.

If you are not comparing mono and binoviewing in the same session then I suspect that what you are seeing is the atmospheric conditions scrubbing detail from the planet and comparing that to memories from when the planet was better placed and conditions were better. When I have compared mono and binoviewing of planets in the same session I have felt that binoviewing gives better results, even though one of my eyes is weaker than the other. If my weaker eye continues to get worse whilst the stronger eye stays as it is, I suppose that I will reach the point where the weaker eye adds so little that I will be better reverting to monoviewing of planets.

Well if you would prefer the 100p size by all means go for it. You can also look out for a decent photo tripod going cheap so that you can use it while standing.

Well done. Now you just have to wait for the clouds to clear so you can try your new scope.

If you do need to collimate it you should back off all three collimation screws a bit first. The screws push against the thin tube that holds the batteries, if you tighten one without loosening the other(s) you will just crush the tube. Place the collimator in your v block and rotate it until the dot is at the bottom of the circle it draws. Tighten up the top most screw a touch. Repeat until it stays in the same place. You will probably find that you only use two screws to change the collimation so the last thing to do is to tighten the other screw to lock it in place.

This telescope appears to be supplied with H8 and SR4 eyepieces, plus a 3x barlow, all in 0.965" format. Of these, only the 8mm eyepiece has any chance of being any use at all and the 0.965" size will make buying additional eyepieces difficult. Low quality but usable H20 and H12.5 plastic eyepieces were still available a few years back and you would probably see an improvement with them, but your best option, if available, would be to return this telescope and start again with a better telescope.

+ side is up towards the on/off switch. Also, it is a good idea to check the collimation of the collimator and/or only use it for barlowed laser collimation of the primary.

Not at all safe. The properties of the mirror (aperture and focal ratio) do not tell you anything about the diameter of the tube and the distance between the primary and secondary mirrors, or the distance of the focal plane above the surface of the tube. Without this information you cannot say whether any particular focuser will or will not work. Based solely on the linked image of the focuser, I would suggest that it looks taller than the focus position shown in the previous video and would not work.

To get all the equipment up the stairs in one go, I think that a backpack that can take at least the mount head and eyepieces should be considered as part of the purchase. Something like @Geoff Lister's Skymax 127 setup(s). I expect similar ideas can be taken from the "Show us your travel kit" thread, except that as the travel is only going up several flights of stairs, a larger scope or tripod can be hand held.

I would definitely keep the neodymium filter in as it increases the contrast in my experience. I think a lot of the problem is likely to be with the low position of Jupiter in the sky. Turbulent atmosphere will remove detail, more so with a larger aperture and by pushing the magnification too high, which I expect you have done with your 240x (maybe) and 342x (definitely) combinations. 120x is a bit on the low side for planetary but I think you should expect to see two clear bands across the planet at this magnification. I would also check your collimation as this can also have an effect on the detail you can see. I have an 8" dob and observed Jupiter for a short while the other night using my Pentax XWs. The atmosphere was definitely the limiting factor with regards to the amount of detail visible.

They are not all the same, but the one you have linked is actually very nice optically despite being a relatively low price. The downsides are that it only has a screw to hold the eyepiece and the lens cell may or may not be threaded for filters. Powermates/focal extenders have a few advantages in that they won't vignette wide field eyepieces, the magnification is constant across eyepieces and eye relief isn't extended. However, the cheapest is three times the price of the linked barlow.

I've used the slightly larger 1145p and thought it was a good scope so I'm sure the 100p would be similar. However, given that you were looking at the 130p before, what put you off that, that doesnt apply to the 100p? Both of these are supplied on tabletop mounts so you will need something to put them on. The 100p is bit easier to mount on a tripod, you just need a decent photo tripod with a 3/8" thread, while the 130p needs some DIY modification.

Given the size of the top lens, there will be vignetting issues with wide FoV eyepieces.

I imagine the only way that might be a possibility would be to contact TV directly, or have one custom made if you know the dimensions. Eyepieces aren't really designed with the intent that users will dismantle them, much less somehow lose an internal part.

No telescope has the ability to zoom, if you are thinking that turning the focuser knobs will zoom in on the object. All the focuser is for is focusing. You need to turn the focuser so that the image of the planet becomes smaller. When the image is at its smallest and sharpest it is in focus. Anything else is out of focus, not "zoomed in". This makes it sound like you already know how to focus properly, but there is no way that the two telescopes will show the same image when using the same size eyepieces. The 50TT has a 50mm aperture and 375mm focal length while the 10" will have an aperture of 250mm and a focal length of somewhere in the region of 1000-1200 depending on exactly what you've got. With a 10mm eyepiece the 50TT will give you a magnification of 37.5x, but the 10" will give 100-120x, so about 3 times the size. Additionally, the resolution of the 10" will be 5x that of the 50TT so under the right conditions you will be able to see much finer detail. However, as already noted in previous posts the atmosphere can often be the limiting factor. Observing when the planet is at its highest in the sky, and observing over vegetation rather than man made structures will help to limit these effects.

Your current telescope and mount combined weigh 16kg and you are finding it difficult to carry. The mount head and tripod for the vx8 weigh 16kg and there is another 6kg for the telescope and a 5kg counterweight as well.

You are always supposed to use the diagonal. With it in place the telescope can focus, there is nothing wrong.

Your #3 and #4 aren't really compatible if you want to do DSO astrophotography, plus the minimum recommended starter mount, the Skywather HEQ5, is way over your budget on it's own. It would probably also be a nightmare carrying it up and down flights of stairs. With you wanting to observe nebulae as well as planets, you want to keep aperture large if possible, but given that you live in a building with 8 floors I imagine the light pollution is quite bad. Can you see many nebulae anyway? I would probably consider the following Skywatcher scopes: 130ps AZ GTi 150p Star Discovery Skymax 127 Synscan

Given that Skywatcher only bundle it with a lightweight version of the 130p, a 150p is probably over the limit. However, the weak point is the tripod, so if you were to buy the mount head, possibly extension, and a better tripod the 150p might be fine.

I would go for the 2x barlow. With visual there generally isn't a great deal of need for a 3x unless you have a very short focal length telescope, which yours isn't. As a personal preference I would go for a Powermate/Focal extender over a barlow but the X-Cel barlows are of good quality if you prefer for all your accessories to match. With regards to the finderscope, I personally prefer to use a RACI finder over a straight through one, as the viewing position is more comfortable, but this does require an RDF as well for the initial finding, so you will have to add another finder shoe to your telescope. Alternatively, the Rigel Quickfinder comes with self adhesive bases which are easy to apply (as does the Telrad, but I suspect it would be too large for your scope). Adding heavier finders does change the weight distribution but as your scope is in rings this won't be a problem, you'll just have to shift it back in the rings a small amount to get the correct balance.

There are really three things to consider here: The maximum magnification your skies will support The maximum magnification that your telescope will support The smallest exit pupil that you can comfortably use. The first one, I can't be a great help with as i have no knowledge of your skies. However, in the UK , under the jet stream, we often say 200x-250x is about the limit and I don't know of any reason why you can't also reach at least this. I see you have an 8" dob listed so you should have a pretty good idea of the magnifications that you have used with that. Anything that has been useful with the dob is a magnification that your skies can support (at least on some occasions). Moving onto the magnifications that the scope can support, which is what you were really asking about, we can start with the "traditional" limit, which is 50x-60x per inch of aperture. These days everything about your scope is measured in millimetres so it is probably more useful to convert this limit to 2x-2.4x per mm of aperture. However, we can't just take this as gospel and apply it to all scopes, but remember that it was devised using long focus achromatic refractors solely for the purpose of splitting double stars. At the top end of magnification, where the exit pupil is small, the image is dominated by diffraction and the Airy disk is visible around stars. Any scope design with a central obstruction has more diffraction and so I suggest that telescopes with a central obstruction, and short focus achromats which are dominated by CA and SA, have a lower limit. Additionally, most people want high magnifications for viewing the planets for which the traditional limit is often revised as the more conservative 25x-30x per inch, or 1x-1.2x per mm, of aperture. I'm not sure quite when this new limit came about, but suspect that it is partly a result of the increasing use of larger, centrally obstructed designs that have more diffraction and are more likely to hit atmospheric limits. For your ED refractor (a design superior to long focus achromats) I suggest that you are looking for a planetary limit somewhere between these two given limits. Finally, we have to consider the exit pupil and your eye. The exit pupil size can be found easily by dividing the focal length of the eyepiece, by the focal ratio of the telescope it is being used in. Converting the limits above gives us corresponding exit pupil limits of 1mm-0.85mm and 0.5mm-0.42mm, which equates to a eyepiece focal lengths approximately equal to the focal ratio of your telescope, or half of it for quick in the field selections. As well as the image becoming more blurred due to diffraction as you decrease the exit pupil, you will also notice an increase in the visibility of "floaters" in your eye(s). This will vary from person to person and there is no real way to determine where your limit is, aside from trial and error. If you want to reduce the effect of floaters at high magnification then using binoviewers will help, as your brain will use the signals from both eyes to filter them out. Your current 6.7mm eyepiece gives an exit pupil of 0.89mm, so right in that lower limit, so with an ED refractor, which I think can push those limits I would definitely give a 5mm a go.