Ricochet

Yes, massively better than my old Starguider pair (same as the OVL). Additionally, you shouldn't get the problems with eyepiece tilting that screw/compression clamps can cause. They are 1.25". 2" eyepieces would be impossible to binoview, even some 1.25" eyepieces are too wide.

Starguiders make very comfortable binoviewing pairs. At slow telescope focal ratios (or short with a barlow/gpc in front of the binoviewer) all of them are well corrected. Their coatings aren't as good as those on the Baader Morpheus and you might see some reflections or ghosting from bright objects. I happily used a pair of 25s for a long time before upgrading to 24 Pans.

Focus on a star with an eyepiece you plan on using with the binoviewer. Read the number off the scale printed on the focuser. If you are using a different diagonal to the one you will be using with the binoviewer you will need to take the difference in their light paths into account. Compare that number to the table in the maxbright 2 manual.

I think the inner 60° of the XW is the same quality as the Delite. With the XWs you get an extra 10° and with the Delites you get a smaller, lighter eyepiece that is more suitable for small scopes or binoviewers.

Nice choice, stick with that then! 🙂

Historically, the empirical optimum for planetary observing is 25X - 30X per inch of aperture. This equates to 1X - 1.2X per mm of aperture or an exit pupil of 1 - 0.85mm. Multiplying the exit pupil by the f ratio of the telescope (f11) gives the focal length of the eyepiece(s) required for these limits. That means that in your f11 scope your optimum planetary eyepiece is probably in the range of 11 - 9mm and equates to magnifications in the range of 150X - 183x. These are good magnifications for observing Jupiter at and in the UK are high enough that you will often be hitting atmospheric limits as well as/before telescope limits. There may be nothing wrong with your current barlow and your troubles may stem from the fact that every time you try to use one you are pushing the magnification above the limit of your eye/telescope/atmosphere. Your existing 10mm Ultima edge is a decent eyepiece and the one I would be using if I were you. The 8-24mm zoom you have is nowhere near as good an eyepiece and probably degrading the image significantly. If you really want a zoom the Baader is a decent option but probably not as good an eyepiece as your Ultima edge. Beyond that there is a Pentax 8-24 zoom, the new APM 7.7-15.4mm zoom or high end spotting scope eyepieces adapted for astro use. Personally, my preference for planetary viewing is to use binoviewers. Using two eyes gives the optical illusion of the image being larger at the same magnification, allows your brain to process the image from both eyes to give a clearer image and makes for a relaxed viewing experience. Binoviewers have a long light path, typically about 110mm, which to use natively requires a focuser that can be wound in by the same distance. To get around this a barlow or gpc has to be added to the binoviewer to move the focal plane out of the telescope so that the focuser does not have to be wound in so much. This results in high magnification so eyepieces of longer focal length must be used compared to monoviewing. I recently received a pair of Baader Maxbright 2 binoviewers and they are a truly excellent piece of kit. Using the 1.7x Newtonian GPC they require 31mm of back focus (winding the focuser in) compared to the focus position when monoviewing (according to the specifications, I haven't measured this myself). The GPC also requires a 2" focuser fitting. However, they are quite expensive, you then need two of each eyepiece and I don't know what the current situation is with the supply chain. It took two years for mine to be delivered due to covid issues.

This isn't a 2" Clicklock, Don, it's the 2"-1.25" reducer so it doesn't have the screws around the bottom. It does have one screw at the top opposite the pin. Someone asked on the Baader website if this screw could be loosened to rotate the pin position but Baader replied that it cannot and so I haven't tried it.

The focuser is a great upgrade and I wouldn't be without it now. I didn't actually realise quite how bad the original was until I used the replacement. With regards to the Clicklock you can also use the one with the micro focuser at the top (it's a t2 thread on top of the diagonal). I went for the reducer variant on my diagonals as it has the lever arm and a collet whilst the micro focuser grips with a pair of rollers. The downside is that the position of the lever isn't adjustable and is probably orientated randomly with respect to the threads on the underside of the Clicklock.

I've taken an 18mm Starguider apart before, it's relatively easy. You just have to be really careful when cleaning to make sure you don't reassemble with any dirt or marks inside of it.

I'm about to blow your mind. Wait for it... Well it blew my mind at least when I discovered you can just unscrew the original eyepiece clamp. 😂

These are the people who I have suggested the OP goes to see: They are perfectly suited to advise the OP and have a showroom full of telescopes half an hour away from where the OP lives. I know from personal experience the service they provide and can recommend them without hesitation to anyone. Yes, you pay more to buy new, but you're paying for the wealth of experience and backup of a specialist retailer and a manufacturer warranty on your purchase. If you buy second hand you have to have the experience and knowledge to assess whether you've bought a peach or a lemon and the conviction in your assessment to immediately demand your money back if it is the later. You and I might be able to make that assessment but the OP can't. Buying new they have years of backup to get any faults rectified.

I disagree with the idea of buying a used scope. Instead I think it is better to buy from a specialist astronomy retailer who can give you after sales support and advice and who can actually assess whether your telescope is faulty should you have trouble with it (and if it is repiar/replace it). With that in mind, once you have got an idea of the type of telescope(s) that you might want, book an appointment to visit Tring Astronomy Centre and have a look at all the different options in their showroom. Just remember that: Everything looks a bit smaller in the showroom than it will in your house Large telescopes don't go up and down stairs easily (so storage downstairs or in the shed/garage is best for them) If you store the telescope assembled a dobsonian base takes up less floor space than a tripod At night when your muscles are cold you're more at risk of injury so you can't lift as heavy an object as you can during the day.

In the very specific example that you are going to use Plossl eyepieces then yes, a 10mm would be more comfortable to use due to the greater eye relief of longer Plossls. However, if you were going to use a more modern design, for instance BST Starguiders, which are a standard upgrade eyepiece, then all of the line is fine at f12 so a 3X barlow would be totally fine with any of them. In the Starguider line the 5/8/12 are fine with no barlow at f6, and I think the 5/8 might even be fine at f4 but I need to have another look through a similar system to be sure. However, you need to get this idea of 150X magnification out of your head. For planets the empirical value is 1x - 1.2x aperture and for DSOs it is 0.5x aperture. On top of this the telescope you have has a spherical mirror instead of parabolic and at f4 the spherical aberration will blur the image which will lower the optimum magnification even further. I would not be surprised if you had to consider 50x as the maximum for this telescope.

A good quality barlow will not make the view through your hypothetical 80/200 telescope worse, but that does not mean that it will be as good as an 80/1000 telescope. In general a telescope with a faster focal ratio will have larger aberrations than a slower scope of the same design type, aperture, glass types etc. Once those aberrations from the primary are in the image, a barlow will not remove them. Similarly, each eyepiece will have aberrations and each eyepiece will perform better at longer telescope focal ratios. In this case you may find that adding a barlow and using longer focal length eyepieces is preferable to using short focal length eyepieces. For example if you use a generic 4mm plossl in an f4 telescope it will not cope with it well, and the image quality will be terrible at the edge of field due to eyepiece aberrations. If, however, you were to use a 5x barlow then the effective focal ratio the eyepiece sees is f20 so you can use a 20mm plossl and have the same magnification and fielding view as you would by using the 4mm plossl with no barlow. As the light cone is so much shallower at f20 the plossl will have no problem with it and eyepiece aberrations will be minimal so your image will have only primary aberrations. More modern eyepiece designs tend to use what can be thought of as a barlow built into the nose and so shorter eyepieces may be better than longer ones to begin with. In practice it would be very rare to use a 5x barlow visually, in fact even a 3x barlow will often be of no use in anything other than extremely fast telescopes like yours. It is also worth pointing out that the 2x aperture limit is an empirical estimate based on observing double stars with very slow achromatic refractors. For other targets and other telescopes it doesn't necessarily apply. I would guess that the celestron firstscope would be very unlikely to be able to reach this limit without the image suffering.

I know, I almost fainted when I saw the order completed email. 😂 I wouldn't say that, that looks like a quality bit of kit you've got there. 👍 Something else to add to my list of future purchases. FLO, but it's still showing as out of stock so there must be more on back order than arrived in the shipment.

I think I've been waiting two years to make this post... Yeeeeeeeaaaaaaahhhhhh 😁😁

Nothing entry level about Naglers! I'd start with those. Which ones do you have? Also, in order to make suggestions we need to know how much you are willing to spend on each eyepiece.

Yes. Bresser and ES are the same family of companies and so any faults in ES equipment will be dealt with by Bresser for free providing you are the original owner and have the receipt to prove it.

The Baader finder shoe is the one that is usually recommended. Any finder with a central screw hole/slot should be fine as you only need to use one of the existing finder shoe holes.

The problem is that in my experience a decent spotting scope has to have ED glass, which is going to cost more than your budget. If you get lucky you might find a 65mm Celestron Regal or Pentax EDA for somewhere around the £200 mark and then be able to use your existing 1.25" astro eyepieces with it. Any other brand with specific bayonet or thread attachments will require buying scope and eyepiece as a set which probably pushes the price up even further. There are also 50/56mm Celestron Hummingbird ED scopes that you might find second hand at the top end of your budget. I had a quick look through one once and got the impression that the bundled zoom wasn't really up to the task but it's a 1.25" fitting so again you could use your existing eyepieces instead. A cheaper alternative would be to look for a small Mak to use as a spotter. If you keep the aperture small then the focal length is short enough that the widest field of view won't be too restrictive, especially for your planned use of watching planes some miles away. A 90mm Mak is probably the largest you would want to go and a traditional astro Mak would be fine so long as you aren't taking it out in the rain. A little Mak that is marketed as a spotter, waterproof and got some good reviews around these parts is the SvBony SV41. Have a read of the thread linked below and see what you think. Again, the supplied zoom appears to be the weak link so factor in the cost of a 1.25" adaptor. For any of these options you'll want to add a cable tie sight to the dew/sun shield so that you can aim it without moving your eye from the eyepiece. I've got one on my spotter and it's excellent for daytime use. See the pictures in this forum thread for details on how to make one. If you've got multiple eyepieces of different heights then rather than using a black cable tie and cutting the top for one eyepiece you can do what I do and use a "natural" coloured one and mark lines for each eyepiece you might be using.

I recently bought a 72ED and when I take it out for lunar the 4 and 6mm SLVs are the eyepieces I've found myself taking out. They are comfortable, well corrected and lightweight with good transmission, but they only have a 50° field (45° actually for the shorter SLVs). The Nirvana et al have a much wider 82° field which you may prefer. The 4mm Nirvana is reportedly very sharp (at least in the centre) but I would expect to not have quite as good transmission as the SLV with a higher chance of reflections from bright objects. Either would be a good choice, it just depends whether you want to go with a slightly better optical quality or a wider field of view.

The difference is that the Starguider/TS ED is a good line of eyepieces whilst the 66° line are a waste of money. At F6.5 the longer Starguiders (18,25) won't be great near the edge of field but I am sure the 66° will be much worse. No, buy the optically better eyepiece whatever the eye cup design. If you need to wear glasses you have to look at the eye relief but without glasses just buy the eyepiece that matches your needs. Despite the adjustable eyecup the Starguiders do not have enough eye relief for glasses. It is how far your eye must be from the lens and the same for everyone. It has nothing to do with focus, which is how far the eyepiece must be from the objective.

I thought the original focuser on mine was bad and consider both the double stack and focuser upgrades equally beneficial. There is a sweet spot for detail with these scopes and with the original focuser it wasn't central. Additionally, when I was using the original focuser I used to spend a lot of time fiddling with the pressure tuner to try to keep the detail high. When I upgraded the focuser I discovered that it wasn't the tuning that was the issue, it was the original focuser not holding focus. As for the options, when I upgraded there was a double speed moonlite and both single and double speed feather touch focusers. Moonlite have moved to motorised focusers so I don't think they will be an option unless you can find one second hand, which is unlikely unless it comes with a scope. As for the feather touch options, I believe they are in short supply due to covid supply chain issues but should be available in the future. I chose the double speed feather touch and find that I use the fine focus all the time so that is the one that I would recommend.

The 18mm BCOs make a nice binoviewer pair if you don't mind them only having a 50° field. However, you shouldn't buy any new eyepieces until you have your binoviewer and have found a barlow that will allow you to focus and have calculated the effective multiplication that it gives when paired with the binoviewer. Once you have that you can calculate the eyepiece focal lengths you need, rather than buying a pair of eyepieces that may or may not be of use to you.

Thanks, that's exactly what I wanted to know.