Ricochet

What you are calling a star test is not a star test, just the view of the inside of a very out of focus telescope. The amount you defocus for a star test is very tiny, maybe a millimetre of focuser travel either side of focus. It is the diffraction rings and effects on them that you want to be looking at. Looking at the photos down your draw tube it appears that your secondary is not centred under the focuser. At a glance it looks too "high" and too close to the primary (to the right in the photo). If centring the secondary and then aligning it with the primary consistently lifts it up above centred then I think you need to adjust the "vertical" spider supports to bring it down a touch.

Both Orion (USA) and Skywatcher are Synta brands. The two telescopes are probably built at the same factory and will be the same quality. You should note that the Orion branded version is a push to scope, whilst the Skywatcher branded one is a full go to scope. With regards the astrophotography, this has wildly different requirements and will require a different set up to visual observing (a Dobsonian is not suitable). It is also not a simple point and click exercise like daytime photography. The book "Making every photon count" is the first purchase you should buy if this is a serious consideration.

If that doesn't work, astroboot are probably your best bet. They sell parts salvaged from damaged telescopes so it's the sort of thing they might end up with. Alternatively, you could get an appropriately sized 2" Baader Clicklock and 2"-1.25" reducer, but that is a much more expensive option and if you're upgrading to clicklocks you might prefer to upgrade the focuser itself first.

The skywatcher dobs come with a 1.25" adapter and a separate 2" adapter , so you need to find the second adapter and put that in the focuser instead of the 1.25" one when you switch to a 2" eyepiece.

Out of interest, which distortions do you notice?

I think photos would help in this situation. "Completely off" sounds like either the secondary stalk has become unscrewed from the spider or the mirror has fallen off the stalk.

Be aware that using the turret requires about 35mm of focuser in travel. With the 130/eq2 I doubt that you have that much available.

I think there is a good chance they will work well with any scope. If you consider that your 4mm something like a 20mm eyepiece with a 5X barlow in the nose then the light cone reaching the "eyepiece" part is always going to be narrow whatever the scope and that should be quite well corrected.

If you use the barlowed laser method you effectively turn the laser into a red torch that illuminates the central area of the primary mirror. You can then collimate using the shadow of the centre doughnut rather than the laser itself so if it is slightly out it will not matter.

1200/6.7=179X Depending on atmospheric conditions this could be the ideal magnification. In fact this year I usually have to be below that due to the low altitude of the planets.

For collimating the secondary mirror, yes. In fact the sight tube part of modern "cheshires" is vital. For the primary mirror the barlowed laser method is a great way to collimate if you cannot reach the collimation bolts whilst looking through a Cheshire and does not rely on the laser being properly collimated itself.

Given the reports on the quality of that style of telescope it isn't worth looking for a corrector lens. In fact even if you had a complete one the advice would still be to scrap it and buy something else.

The 200/1200 OTA is the Dobsonian version. This makes it longer and more prone to vibration than the 200/1000 that is supplied on the eq5. I think that there is absolutely no chance of either the eq2 or eq3 being stable enough. Even the eq5 may not be enough. You would be much better off building a new dob base for the OTA for both stability and ease of use.

It's a Stellarium (PC version) screenshot.

It's worth remembering/noting that the comparisons for that report were done under dark skies. Where you are also combating light pollution the narrower OIII filters will probably perform better on more targets.

I would expect the Nirvanas to be at least as good as the Starguiders, but with a wider view and shorter eye relief. The only problem is the lack of focal lengths in the range, and I expect you will find that you also want something around 10-12mm.

That's the sort I use. Make sure you get one with a silicone tip rather than hard plastic tip in case you knock the lens with it.

Well, if you have success with cleaning the finder you might decide to have a go with the eyepiece too, but this will have several lenses and spacers and so is a more difficult task. If you just want a like for like replacement then I think the eyepiece supplied with your scope might just be a GSO Superview so you can search to see if you can find one of these. An alternative that is about the £100 mark and pretty well reviewed is the Aero ED eyepiece. If you want to spend more money on a better eyepiece then the 28mm 68° Explore Scientific (previously Maxvision, Meade SWA) would be a good choice, or the APM 20mm/100° or 30mm Ultra flat, but these are both large, heavy eyepieces.

No. Not aligning the finder might mean that you struggle to find something because when you switch from the finder to the telescope it is not in the field of view. The only ways I know to see the secondary shadow, if that is what you are seeing, are to use an eyepiece that produces too large an exit pupil, which I think can't be happening here, or to be out of focus. You say that you are surrounded by trees and that when moving "up" from the moon you see this line. Are you actually raising the telescope up or are you moving it down so that the moon appears to move up in the eyepiece? If the later, is it possible that it is the shadow of one of these trees that you are seeing? This is impossible. The focus positions for the moon, planets and stars are so close that when one is in focus the others are so close to focus that they are essentially all in focus. If you focus on one thing properly and then switch to another there is no way I can think of that you will see the secondary shadow.

Before you go buying a new finderscope, why don't you have a go at dismantling and cleaning the one that you have? From the images online it looks like you should have a standard Synta RACI 8/9x50 finder and they are quite simple really. Everything just unscrews and the worst that can happen is that you end up needing to buy a new finder. See the image below: Don't drink any beers. Hold the diagonal and rotate the eyepiece as shown by the red arrow. Inside of the eyepiece is a crosshair that you will have to carefully unscrew. This is may also be the spacer that holds the eye lens in position. If the lens comes out make sure to note which way around it goes. Hold the main tube and rotate the diagonal as shown by the yellow arrow. This will give you access to both faces of the prism. Alternatively, the back plate of the diagonal can be removed and you should be able to remove the prism completely. Turn the lock ring a small amount in the direction shown. This will release the objective lens cell. Unscrew the lens cell as shown by the blue arrow. You can now clean both sides of the objective lens. If it is an air spaced doublet and water has seeped between the two lenses there will be a ring inside that you can unscrew to remove the lenses. Again, note which way around these lenses must go. Good luck.

When you next see these specks loosen off the screws holding the eyepiece and barlow. While looking through the eyepiece, hold the barlow with one hand and rotate the eyepiece with the other. Next hold the eyepiece still and rotate the barlow. If the specks rotate while you are rotating the eyepiece or barlow that is the thing that is dirty. Finally, shake your head and rotate your eyes quickly and then quickly look back through the eyepiece. Have any of the specks moved or disappeared? If so you are seeing the floaters in your eye. This is very likely if you are using a barlow with a Mak as the exit pupil will be very small. I believe there is a type of laser surgery that can remove them, but a cheaper option is to use a binoviewer for high power lunar and planetary. When using two eyes your brain will filter out the floaters.

It would cost thousands of dollars to buy the equipment needed to take those photographs, but due to the way that the eye works you are not going to get views through the eyepiece like that. DSOs in particular will differ from photos because they are so faint that you will be using your dark adapted vision to view them. You won't see any reds and only blue/green on the brightest objects. Most DSOs will simply appear as shades of grey. Planets are more akin to the photographs but will still appear small. I recommend you start by reading through the following thread: Mechanically fitting your camera to a telescope should be relatively easy. Initially, you need an E-mount to T-thread adaptor so that you can use standard t-thread accessories/fittings, probably a t-threaded nosepiece or barlow. However, being able to get the camera to focus with your chosen scope and then get usable data out of it might be more difficult. It is worth pointing out at this stage that observing through a telescope, planetary astrophotography and DSO astrophotography are all very different things requiring different setups. In addition, astrophotography is not point and click, but requires gathering lots of data and then processing it on a computer to produce the final image later. I think we can rule out DSO astrophotography immediately as you simply don't have the budget to get anywhere close, and it seems like you might be mainly interested in planets. This is also good because planetary astrophotography and visual observations have much more similar requirements. For planetary astrophotography you can get away with an alt/az tracking mount and I also think this will benefit your daughter as manually tracking an object at higher magnifications is more difficult. The telescope that immediately springs to mind is the Skywatcher Skymax 127 Synscan AZ GoTo. Given that you've posted a budget in Dollars I don't know how easy it is to get hold of in your location (FLO do international shipping if required) and I assume that the price is going to be a bit over your budget, but it is the system that initially springs to mind for what I assume is mainly shared visual with your daughter and a little bit of dabbling in planetary astrophotography thrown in.

This is a very good point. The graphs are only useful if they accurately reflect the performance of the filter (and you understand how to interpret the graph).

I think that the best tool for positioning the secondary under the focuser and aligning it with the primary is a sight tube. Most modern Cheshires are combined Cheshires and sight tubes, and the red FLO Cheshire is an excellent and accurately machined example. For aligning the primary the easiest accurate tool is the barlowed laser. You want a laser that you can collimate with a 45° face and a decent barlow that is accurately machined enough not to tilt in the focuser. I also use a small Cheshire with the sight tube crosshairs removed to check the primary (I can also use this in place of the barlowed laser but it requires more practice). With regards to the Hotech, I did once buy one, but returned it to the seller because the self centring and/or collimation was off and it did not give repeatable results. I was also unimpressed with the quality of the laser image it projected. If you are going to buy an expensive laser for alignment of the secondary I would go for a Glatter option.

Practice, I think. Changing scope won't make them any bigger unless you also increase the magnification, and you can do that more cheaply with eyepieces. As it stands you can already get 240X and 300X which might be too much for Jupiter itself and that really is the interesting object. I would be more inclined to get an eyepiece or binoviewer set up equivalent to 7mm.