Ricochet

I don't recall anyone reporting such an issue but there will be be a bit of variation in sizes and at the cheaper end of the market the tolerances are probably not quite so stringent so it isn't a massive surprise that this could happen. If you opt for a replacement you might find that it fits perfectly or you could put the refund money towards a different 15mm if that is a focal length you want to stick with. A 15mm Starguider would be the obvious choice, but there is a nice 15mm Panoptic in the classifieds if it is within your budget and you don't mind the tight eye relief.

If you've got any flocking material I would recommend flocking the inside of the telextender between the two lens groups, as this really cuts down on stray light and improves the telextender. I've not noticed any vignetting from the slight reduction of internal diameter in my (Meade branded) version.

What is the size of the bolt through the AZ3 tripod? M10 perhaps? If you find a M10-3/8" adaptor then you could screw so M10 threaded rod through the bottom of the tripod, and secure it with appropriate nuts and washers. You could then fit the adaptor to the rod and fit your preferred mount head to that.

Generally speaking, this is not true. Good collimation is vital for high quality planetary and lunar viewing. What other lenses and barlows do you have? Assuming that you don't have any collimation tools then the best thing for you to do is to point your telescope at Polaris. Choose an eyepiece that is approximately equal to your focal ratio, or an eyepiece-barlow combination to simulate one. For your F4 scope, you want a 4mm eyepiece or you could use an 8mm eyepiece and a 2X barlow. Precisely centre Polaris in the field of view and defocus the image enough to make the diffraction rings more obvious. From the in focus position you will probably move your focuser perhaps a millimetre or two out of focus. Check that all the rings are concentric inside and outside of focus. If they are your collimation is fine. If the rings are not concentric and the inner rings are all squashed to one side of the largest ring then the collimation is out. Carefully move the star around the field of view and see if when the star is off centre in a certain direction the circles become concentric. If this does work then you will probably want to look at buying a cheshire and centre spotting the primary, if this is not already done. However, the focuser on your telescope is not particularly sturdy and the weight of a heavy eyepiece such as your new zoom could cause the focuser to sag, which will throw the collimation off. Check how the collimation looks with both your zoom+barlow, and your 10mm+barlow (if you have one) and compare the differences. Some people have shimmed the drawtube of this kind of focuser to reduce the amount of flex when extended. If you find this is a problem for you then you might also want to investigate this option. Additionally, as your telescope is F4 you will have both a high level of coma from the telescope, and also your eyepieces will have their own aberrations due to the steep light cone entering them. If you do all your planetary observing with a 2X barlow in the focuser, then from the perspective of the eyepiece the light cone is a much shallower F8, and eyepiece aberrations will be greatly reduced.

Yes, it will be. Fast achromats are not planetary scopes due to the amount of chromatic aberration they exhibit.

Those could easily be diffraction spikes from something like a washing line or power line between the target and camera, rather than an issue with your equipment. Try a couple of targets in different directions and see if the issue persists.

Yes, it is because you own an astronomical telescope. If you do what I did, and buy a solar telescope, the weather will change so that it is cloudy all day as well as at night.

I agree. I tried that once and discovered that I used the telescope less often. I've added a bungee based system to mine so that the force exerted varies automatically with the telescope angle. It's not obvious from the photo below, but at high altitudes the bungee actually pulls the front of the telescope "down" to counteract the weight of the finders, focuser and eyepiece(s) hanging over the back of the tube.

Are you able to take some photos of the telescope and post them here so that we can see what you have? If the telescope has been disassembled it would be best if we could see what you have in case there is any more amiss than the focuser being disconnected.

The descriptions fast and slow refer to the focal ratio of the telescope, which we can find by: focal ratio = focal length / aperture These days we might say that f5 or lower is fast and f8 or higher is slow, so your maksutov is definitely slow. This is good news for you as it means most eyepieces will be "well corrected" when used with your telescope. A good example of this is your 18mm Starguider. In your telescope, a star will be a nice point of light in both the middle of the field of view and at the edge of the field, whereas used with my f6 telescope a star is a nice point of light in the middle of the field, but becomes more of a large D shape as the star is moved to the edge. The reason for this difference can be understood if we consider how the light is bent as it comes into the telescope. Light coming into the telescope all across the lens is bent so that it all meets at the focal point, as shown in the image below: We can see in the images above that the angle of the light cone at the focal point (on the right) is much larger in the fast telescope example. It is much more difficult to correct this steep angle and this is why some eyepieces perform better in slow scopes than in fast ones. Historically, the terms are taken from photography, where lenses are described by their focal length. In this case the focal ratio gives the size of the aperture when you know the focal ratio, so if you have a 200mm photographic lens, a ratio of 1/f5 is an aperture of 40mm and a ratio of 1/f10 means it has an aperture of 20mm. You can see that the 1/f5 lens, with its aperture of 40mm, must let in more light than the 1/f10 and so it can take a picture faster, hence the term "fast". However, when we talk about telescopes we define them by their aperture, so a 200mm telescope that is f5 has a focal length of 1000mm and a 200mm telescope with a focal ratio of f10 has a focal length of 2000mm. In this case both telescopes have the same aperture, and so neither telescope gathers more light than the other, they just have different image scales photographically or magnifications when used with a specific eyepiece. The photographic meanings don't really apply here, but we still use the terms as a useful shorthand to group telescopes according to their focal ratio.

There's a 40mm Maxvision in the classifieds at a bit of a bargain price. The Maxvision is a rebranded Meade SWA and optically the same as the ES68.

Search on eBay for binocular tripod adapter or mount, you'll find hundreds of listings.

The Altair is the same optically as the APM, so if you search for that you will find more reviews. The general consensus is that they are very good eyepieces and one would be a worthy alternative.

What is the depth of your 2" clamp? Mine is 2mm solid - 8mm compression ring - 2mm solid.

I've had a Bresser 8" dob for about five years now. My top accessories are: Warm clothing, think ski gear levels of warmth/layering. I always say to dress for a season colder than it is, so in winter it is really cold to say the least. An adjustable height observing chair. The scope is too low to stand (stoop) at for any real length of time. Being able to sit makes things much more comfortable and allows you to concentrate and see more. Some sort of star chart or planetarium software so you can find things in the sky. Having Sky Safari on my phone is still a great help when I've forgotten where something is or need to check the star hop. Additional eyepieces. My first buys were the 8 and 12mm Starguiders. I initially thought the 8 would be the one I got the most use out of but the 12 proved to be the one I used more often. Unfortuantely, the longer Starguiders do not perform well in this scope and so more expensive eyepieces will be needed for low power views. You will also want at least one 2" eyepiece in your collection at some point, either 20mm 100°, 30mm 82° or 35/40 68° depending on light pollution. A good collimation tool. I bought the red FLO premium cheshire, which is an excellent choice and I don't think anyone should scrimp and use a cheaper cheshire. The only alternative I would be tempted by is the concenter collimation tool. Baader clicklocks. The excellent focuser is let down by the eyepiece clamps, particularly the 2" clamp, which will tilt any eyepiece with an undercut. Clicklocks solve this and also make changing eyepieces a lot quicker and easier. A 9x50 RACI finder. My MK1 8" Bresser came with a red dot finder so adding a magnifying finder made finding things a lot easier. The 4-5° field is significantly larger than the <2° field the telescope itself can show with a widest field eyepiece. (The supplied 26mm will show somewhere in the region of 1.1°.)

I wouldn't worry about the primaries being "non-collimatable". A telescope only requires regular collimation if things flex and move so that the collimation is thrown off. The (plastic) mirror cells should be pretty resistant to such movement and so recollimation shouldn't be needed once set. However, if collimation out of the factory is not good then collimating the telescope on arrival is more difficult than with a traditional cell with adjustment knobs/screws. The biggest consideration that I would have is that generally these telescopes have had the non-collimatable cell fitted as a weight saving measure. As a result they will also have small plastic focusers that will probably want shimming in order to tighten them up and prevent/reduce the draw tube flop. I believe TS sell a replacement focuser that can be fitted to such models should you find it necessary in the future.

The dial on the side of the finder moves the finder side to side, the dial on the underside at the back moves it up and down. Any deviation from these lines of movement is just inaccuracy in the screw thread that the finder moves on and so you might have to account for that in your adjustments.

No. You have stated that needing to find something to raise the scope up is an issue, and a Newtonian has the eyepiece at the top. With a Mak the eyepiece is at the bottom so your problem will be even worse. Better than what? The dob base? I don't see that it can be better than the azgti, which looks smaller and easier to pack, and can have its carrying capacity/stability improved with a better tripod, whereas the star discovery tripod is not upgradeable.

The top item in this photo is the bottom half of your barlow. You should find that the two screw together. The middle item might be your 25mm plossl. The silver part in a previous photo looks like it is just a sleeve that would normally be covering the black part in the middle.

That's the problem I found when I tried using XWs in BVs. I also found that in the horizontal direction only 60-65° is visible simultaneously with both eyes so there is a resolution drop before things get to the field stop. As a result my current plans are based around Delites and a pair of 24mm Pans.

Your barlow is either incomplete or in several pieces. The one you have is the same as the one sold by FLO under their Astro Essentials brand. Generally your photos are too close or the wrong angle to tell what we're looking at or if there are parts missing that you have not considered.

I think that you should rethink your eyepiece choices. Any ortho eyepiece will have a narrow field of view and at shorter focal lengths an utterly miserable eye relief that is just not nice to use. Baader Morpheus, Pentax XW and Televue Delite/Delos will all give you planetary views just as good as the orthos but with a much more comfortable eye relief.

Did you buy this new and still have the original receipt? If so, you have a 10 year warranty and should contact Bresser, who will then repair it for you (or maybe just send you a new part).

Given that you have frustrations with both the telescope and mount, I think replacing the whole setup sounds like a reasonable plan. Personally, I think the most important consideration is that you have to carry the whole setup in one go. If it is too big/heavy/awkward then you will find yourself finding excuses not to use it. Based on that, I think I would immediately discount the 150/eq3 option, and any other equatorial mounted system so that you do not have to carry counterweights. To me, the stand out option from the ones listed is the 127 Mak on the AZ5 mount. In terms of size the 127 seems to be the goldilocks size for Maksutovs, with the 102 not quite having a large enough aperture and the 150 being too heavy. There have also been a fair few pictures on this forum of a 127 Mak and a mount head packed into a rucksack, which would be a good option for you as you have to carry the telescope to your observing location. With regards to the mount you choose for your 127 Mak, the thing that is great about the AZ5 (or the AZGti if you want a goto option), is that it uses a standard 3/8" photographic connection, which means that it fits on any decent photographic tripod. Photographic tripods are generally designed to be transportable, which for you is ideal. The tripod supplied with the mount is reportedly not great, and doesn't appear to be particularly compact, so I would recommend replacing it with a tripod from Manfrotto, or some other good quality manufacturer. Luckily, photographic tripods are quite common and so there is usually a good supply of them in the second hand market if there ins't enough left in your budget for a new one.

FLO currently have the following two scopes on their offers page if your budget stretches to either. The Mak is more of a lunar/planetary scope and the short refractor is better at low power, wide field views (i.e. not lunar/planetary). Nexstar 90 SLT Startravel 102 GTe