Ricochet

Just so you are aware, there is a small grub screw on the side of the clamp that needs loosening before you can unscrew the clamp from the extension.

That's a hexafoc focuser, right? If so the thumb screw near the finder screw needs doing up. You loosen it to change the angle of the focuser and lock it once it is in your preferred position. The thread between the focuser and extension is the same as between the extension and eyepiece clamp. If you can mount the wheel between focuser and extension you can probably mount it between extension and clamp, it depends how far in the eyepiece clamp protrudes.

I've got an 8" dob and for DSOs all I use is a 28mm, 14mm, 10mm and a 2x barlow. Most DSO viewing is best at relatively low powers and, in the UK at least, the atmosphere will often be the limiting factor for planetary observations. For the most interesting planets, Jupiter and Saturn, a 7mm is probably the sweet spot on most nights.

You can find those quite cheaply on eBay if you don't mind the wait while they arrive from china. Here's one such listing

It sounds to me like your eye positioning isn't correct. A barlow at the front of the binoviewer will increase the eye relief of the eyepieces so you have to consider the distance you hold your head away from the eyepieces as well as getting the binoviewer set to your IPD correctly. With respect to the FoV being limited, I've found that due to your eyes not being quite parallel, in the horizontal direction you can only see about 60° with both eyes at the same time.

Which 130p? If it is one with a 1.25" only focuser then I would start over budget with a 24mm ES68 to max out the field of view. The shorter lengths he can save a bit on by going with Starguiders, BCOs or SLVs while FLO have them on offer.

Easier to put a star in the centre of the FoV and time how long it takes to drift to the edge. Do it a few times in mono view and a few times inserted into the binoviewer/barlow and then divide one average by the other to get the multiplication factor. So long as there is no vignetting of course.

You were out of focus and essentially looking at the inside of your telescope. Always focus your telescope to make the object as small as possible. For your telescope I would guess that actually a 10mm is about optimum for planetary observation. A Baader Classic Ortho would be a good and relatively cheap upgrade over the kit lens, if you don't need glasses and can put up with the short eye relief.

Your current dob has a large radius of curvature so the combined fc might be acceptable. I've got a 14XW and 8" dob that are ok together, but focusing slightly off centre does help. However, if the Tak you are possibly getting is a doublet then it will have a very small radius of curvature and the combined fc will be higher. I would estimate that approximately 99% of the people who complain about fc in the 14/20mm XWs are trying to use them in doublet fracs.

Is that all of the SLVs? I thought that was supposed to be an issue in early examples, but later corrected.

Rotate the Cheshire in the draw tube and see if the crosshairs are centred on the doughnut at all angles.

You say "we" so does that mean your husband is in on it or is it a surprise? Could you visit a local telescope retailer or astronomy society to look at a variety of telescopes and get an idea of what sort of instrument he could manage? A 130mm Newtonian or 127mm Maksutov on an alt-az (not eq!) mount would be my initial suggestions. With regards to brands you can't just go by brand name as the major brands produce everything from excellent to terrible. You have to look for feedback and advice on the specific model or line of telescopes that you are considering.

What has not been pointed out is that the response of the eye to light intensity is not linear. In fact you have to double or halve the light in order to even notice the difference, so while technically a binoviewer halves the light to your eye, as far as the eye/brain is concerned the drop in brightness is only "1". This is the exact same reduction in brightness as changing from a 14mm to a 10mm eyepiece, for example, and I don't think there are many people advocating only ever using one length of eyepiece. For lunar and planetary observation where the objects are very bright to begin with, a small drop of light is not going to be an issue anyway. In addition, there are the advantages of binocular summation. From wikipedia:

That is correct. Really you should adjust the centre screw, which pulls on the mirror, and the outer screws, which push on the mirror, sequentially so that it does not rotate. As you have found it is sometimes easier to hold the secondary support with your hand, but you must be sure not to touch the mirror itself. You should get the secondary support centred as a starting point. The offset should be built into the support and not something you need to worry about. Align the Cheshire cross with the mark on the primary mirror. Not true. If the orientation of the Cheshire makes a difference the Cheshire is faulty and should be binned. The only consideration is to angle the face so that it reflects a suitable amount of light.

This is wrong. The centre screw determines the "height" of the mirror up and down the tube. If you have twisted the screw to turn the mirror then it is most likely no longer facing the focuser properly. Once you have the height set using the centre screw you use the three outer screws to make the secondary appear circular.

I've not used it but I would expect it to perform quite badly. Wide angle eyepieces require lots of elements to get good correction at low focal ratios and using 2" glass the cost adds up quickly. You might find that quite a proportion of the field is lost to distortions.

They've always been very good when I've used them, both in the shop and online. I've had a couple of issues with equipment failing and they were very quick to sort replacements.

I think that the instructions for the Baader wonder fluid do actually say that you can use it for cleaning mirrors, but the suggested method is to entirely submerge the mirror in the fluid. Cost wise it would probably be cheaper to buy a new mirror/scope. 😲

Contact Bresser. They have a good warranty department and are quite likely to fix the focuser if you let them know you have a problem (and the receipts!).

I believe there is a decent 60mm in the classifieds. As to the original question of what defines a serious telescope I have three proposals to be argued over discussed: A telescope sold by a "proper" astro retailer rather than by department stores. A telescope packaged in a brown cardboard box (or several brown cardboard boxes) A telescope not bundled with a 3X barlow and SR4 eyepiece.

Are you collimating the secondary using your Cheshire first? If you ignore the reflection of the primary and just look at the secondary it is too low. You can raise it using the secondary collimation screws but if the second step of aligning it with the primary takes it back to that same position then I think you need to adjust the spider vane lengths. Of course, that assumes that the laser is accurate. I bought a Hotech but found that the self centring was not consistent and I could not get repeatable results with it. These days I just use a Cheshire and collimation cap as the batteries in my cheap laser (for barlowed laser method) need replacing.

This is not right. I believe that the stalk is threaded both ends and just screws into both the secondary holder and the side of the telescope tube. Check when the secondary support swivels if it is turning on the stalk or if the stalk itself is actually rotating as well so that you know which joint is faulty. Once you have determined that, turn the loose part to tighten it up. If you can get one full rotation you may be fine, but if it is always loose in the correct orientation then I would suggest going back to your retailer and see what solution they suggest (probably replacement). Edit: looking at photos down the barrel of the H130p it appears there is a nut where the stalk enters the tube side wall. If this nut is not fixed to the wall of the tube as the mounting point then it is a lock nut and you should tighten the nut to stop the stalk from turning.

This is almost exactly what I do for DSOs with my 8" f6 dob. 28mm Nirvana, 14mm and 10mm XWs and a 2X Focal extender. Planetary is a different matter because then it's time for a binoviewer and pairs of small eyepieces.

Alternatively, the Celestron X-cell LX/Meade HD60 ranges are pretty similar to the BSTs if any turn up on the second hand market. There are also the Baader BCOs in a similar price bracket, which are better optically at the expense of field of view and eye relief.

This is correct. For visual use the barlow goes in the focuser and then an eyepiece goes into the barlow. This will double the magnification that you get from the eyepiece. For example the 25 mm eyepiece normally gives 1200 / 25 = 48X magnification. With the barlow added you will get 2 x 1200 / 25 = 96X magnification. This will be most obvious on planets and the moon. Stars are point sources so they will never appear any larger, but the space between stars will increase. With regards to better eyepieces for visual use the previously mentioned BST Starguiders are a good choice at a relatively low cost. If you just want to get some quick snaps of the brighter objects that you can see through your eyepiece then you will probably have more luck with a mobile phone camera. To use the Canon you would have to find a way of mounting it so that the end of the camera lens is the same distance above the eyepiece as your eye would be. If you are actually more interested in serious astrophotography then you will likely have to buy a new mount, telescope and camera as visual and photographic setups have different requirements. That is not how you unscrew the lens cell from the barlow. The black part that you show still attached to the silver part is the part that should be unscrewed. Once that part has been removed it can be screwed into the bottom of an eyepiece for approximately a 1.5X increase in magnification.