Carbon Brush

I know that I have used a particular Zeiss varifocal lens for some years, and had good results. So I thought I would take a look at the Zeiss UK site for data, to help with the enquiry. Unfortunately the Zeiss site only shows 'glossy leaflet' type of minimal information. OK I really mean it is next to useless. Us uneducated peasants are locked out of the useful pages. Reminiscent of when I asked (as an industry professional) about the contents of their lens cleaner and they wouldn't play ball. That information is only available to industry users..... But I am an industry user. Look at my email domain. Look up the company on the web site...... In this case we decided to not buy the Zeiss product and went for something we could identify. On my next visit to the optician I will try to grab photos of relevant pages.

Agree absolutely. Another factor is how rapidly they change from far to near vertically. If you choose 'Harry Potter' round lenses in a 40mm diamter frame, it is not a worry. But if you choose letter box shape frames that are only 20mm high, it is a different matter. If you want to use a screen, or read a lot, you don't want a spot 'near' section. Though a large near section may compromise middle/distance results. In the back, or under the counter, the optician has a lens catalogue. It shows the lens characteristics, rather like contour lines on a map. Imposing this over your desired frame will be very useful. Ask to see this if the 'front of house' staff can't (as if often the case) answer your questions. Or go elsewhere. HTH, David.

Biassed opinion coming up. My first proper scope was an 8" newt, shorter FL on manual EQ5. Yes a good combination. I had many many hours of enjoyable viewing. Even after selling this first scope I have always owned a reflector in this size range, or a bit bigger. The EQ mount takes a little while to get your head around, but once learned it is like riding a bike. The scope is a good all rounder. A long FL eyepiece taking in larger objects and magnification up to 400 with the ight eyepiece - and a stable sky. Plenty of light gather. Don't worry about photo use for now. just enjoy the views. An alternative to consider (and save money) is a dob mount version. Again regarded by many as a 'keeper'. You may have heard about collimation. Don't worry. It is easily learned by hands on. A Cheshire or simple (low cost) laser are all you need. Then how often? My experience has been hardly ever unless you throw the scope around a lot. How long does it take? A couple of minutes - unless you have had the scope apart for flocking and cleaning. The nice thing about a reflector is that being simple, you can modify or upgrade with ease. They are basicaly a tube with a big mirror, little mirror and focus tube. all held by few screws. Lots of light pollution from the sides? Flock the tube or use better black paint. Mirror dirty? Bird droppings? pollen & sap? Easily sorted in the sink. Focusser a bit rough or sloppy? Buy another better type. Don't like the finder scope - fit a right angle. Always my first choice though ohers may differ. If you do go for an 8" reflector, take a look at other offerings like Bresser & the FLO 'own brand'. They all are similar, but have different accessories included. HTH, David.

It all depends on the lens. Not all lenses are created equal😁 I have used high dioptre, then high RI when available, lenses all my life. Some have made good spectrometers, others have been definte ED refractor quality. Fortunately most high street opticians do a 30 days refund/reglaze type of service. Ask the awkward questions - don't just accept one recommendation. If you don't get the answers to questions, use a different optician. If you can get access to the books some opticians keep in the back, or under counter, you get answers. The lens manufacturers catalogue of blanks shows not only RI, but variance with wavelength. Another important one for those of us 'of a certain age' is how a varifocal transistions. There are images that look like contour maps. Some lenses have a tiny reading region so you have to move your head almost at every word on a line. Other have a large reading are. HTH, David.

This has been discussed quite few times in other threads. The brief answer above by @michael.h.f.wilkinson is a good summary. I would add (an experienced user) that varifocal lenses are absolutely full of compromises. With my prescription the 'normal' uses like reading, driving, TV and the like are fine. As for odd ball activity like a telescope - that is something else. Try this test...... One eye on a distance light source like a street light at hundreds of metres. Keep looking at the light and move your head around so the light enters from all corners of the lens. You will see the light go from near point, to lozenge, to oval, to blob. Now which bit of the lens will you use for viewing? My choice has been contact lens with fixed focus. This allows you to use any eyepiece (short or long eye relief) and provides a god view - assuming a well matched and fitted cnotact lens. HTH, David.

When I bought my AR102 (shorter FL) used, the seller included everything that had come with the new scope. This included extension tubes and a diagonal. These were necessary when I first tried it. A look at a retailer web site will describe what is in the box. The scope is solely used for solar now so I have almost forgotten about the extensions and diagonal. The 'too short' tube was very useful to accomodate the 115mm path length of a 2" Herschel wedge. HTH, David.

Often refractors require either an extension tube, or a 90 deg adapter to reach focus. The Bresser refractors usually come with a bundle of bits for this purpose. Was it bought 2nd hand? The previous owner may have failed to pass them on. HTH, David.

Hello and welcome to SGL. Good comments and questions from the above. A further question (or three) for you. How much use have you made of the supplied eyepieces? What do you see the problems/limiations of the eyepieces? What do you hope the new eyepieces will provide to justify the spend? HTH, David. Note to mods. It may be useful to move this thread to the beginners help and advice.

A second to @scotty38 If you have a lightweight scope, that has a wider field of view, you will make it easier to produce good images. I'm getting my coat as well😁

Yet another happy Lunt owner. My LS60 came with an upgraded focusser, the work of the previous owner. The original was thrown in with the deal. Yes the stock focusser was a bit basic.

Only 4 weeks to the show at Kettering. More mounts than you you could imagine.......

Hi Stu. My two pennorth, for what its worth. Look for a tripod first. The heaviest/strongest you can find, or lift. Alternatively, are you able to put a pillar in the garden? Location SWMBO, etc. Disguised as a bird feeder or bird bath in daylight hours🤣 I saw a picture of a pillar with mount that thad a fibreglass mock dovecote on top. A Norfolk member used to have a roll off tardis in his garden covering an imaging rig. It looked great - well I thought so. Good luck with the decisions and searching. David.

Just a caution to anyone reading. Weight limits and size limits do vary significantly between airlines - check carefully before departure. Some airlines don't make a fuss, others try to grab your money if you are a millimetre oversize or a gram over weight. Also print a copy of their luggage rules and have it in your pocket. I have (more than once) had to argue with check in staff who have relented only after having their own rules presented to them. Finally. When your scope raises security eyebrows and they want to look in your bag, handle everything yourself where possible. The last thing you want is a tube dropped on a table top, or fingerprints on the objective. Some security staff are careful, others less so. HTH, David.

Welcome to SGL. I used to have an ST102 a long time ago. A very good scope for the ££ spent. It was displaced by something that made a much bigger hole in my wallet!

I don't know what Q3 does on the board, but can make a (hopefully) useful comment. A mosfet like may have a 5A rating, but it can easily get fried. Can something in normal operation cause a higher current? It is a characteristic of mosfets that their ON resistance increases with temperature. Heat them a bit and resistance goes up, causing more heating....... In other words, they can go into thermal runaway once you start heating. These tiny surface mount packages have no mass. In other words they heat quickly. The only way to dissipate the heat is via the copper tracks on the PCB. You can see the board designer has used thick tracks and vias aruond this part. It is obviously intended for high current. A quick view at a reputable distributor (Digikey) indicated the device is no longer manufacturerd. Actually 31m-ohms mentioned earlier by @malc-c for a low voltage mosfet is not something to shout from the rooftops. If I had one of these boards I would trace out the area associated with Q3 to check what is going on, and fit a different device. I'm thinking of something with better ON resistance, or something through hole with a heatsink. HTH, David.

Wow! What a find! I have seen bits like this for real, and discussed on SGL. But not a mount in such good condition. I'm sure some members will be along who know much more. Looking forward to hearing more. David.

Stamford to Kettering. Local for you but a bit too far to walk if you buy anything big, or are wandering around the stands all day🤣

Hi Paul. As you are generally carrying your scope further than house to back garden, I would say that rules out anything that is a decent size on a Dobson mount. You are into a tripod, but what mount? An alt/az mount is easy up/down, left/right. Very intuitive. Great for purely visual. Unless the mount has 'goto' you have to move two controls to keep and object in view. Any photos are limited to a few seconds exposure. However, the stars don't travel up/down. They move in a curved path. Apparently rotating around the pole star. This is where an equatorial mount come in. Point one axis to the pole star. North and about 53 deg above the horizon. Once have located an object, you only need move one control to keep it in view. Learning how to use an EQ mount is not so straightforward. But no rocket science involved. If you have a motor on one axis, it keeps the object in view for you. Now you can attach a camera. alternatively fiddle around with eyepeice swapping, grab a cuppa, and the object is still there. With an alt/az mount you just balance the scope forwards/backwards on the mount and view. With an EQ mount it is a bit omre involved and there are counterweights. It is though a two minute job once learned. The weights mean there are a few more kilos to carry to the field. Then what scope? There are 3 basic choices, a refractor, a reflector, or a compound scope. A refractor looks like a traditional tube with eyepiece at the back. With your budget is going to be an achromatic scope. That means colour fringing at high magnification. Look at Skywatcher Startravel range for examples. A newton reflector looks like a drainpipe with the eyepiece at the top. Colour is great. Generally you get more mirror size (= light gather) for your ££ than with a refractor. Good for looking at dim galaxies. A bigger mirror (or lens) also allows higher magnification. At low magnification you get the bigger objects in the field of view. A good example is a skywatcher 200. A compound scope is an SCT or MAK (yes abbreviations). They tend to be long focal length, so narrow views. Great for the planets and other small objects. An example is the Skywatcher 127. A lot of options there. I have also mentioned only Skywatcher products. There are other makes! I would say your next move is to visit a local (or not so local) astronomy club. Have a chat and a look at what others are using. I don't know if there is an astronomy shop in your area. All scopes appear similar size/weight on a web page! Having a hold and look is an eye opener. If you buy a package of scope + mount + tripod, remember the tripod and mount are the flimsiest the manufacturer can get away with. Any package you buy has compromises. If you go for electronics and motors on a budget, something has to suffer. No amount of clever electronics and software will make up for a scope lens made from a milk bottle placed on a wobby tripod. Whatever you end up buying, if new, use a dedicated astronomy retailer. He can (and will) provide after sales support. He wants to see you again for eyepieces, another scope, etc. DO NOT buy from Currys, Amazon, ebay, etc. They cannot help with problems, only offer refunds. If you are tempted to buy used, avoid gumtree, ebay, etc. There is some stuff there fit only for landfill. Unless you know what you are looking for, you can get bitten. When you have accrued 25 relevant posts and a month of membership on SGL, that gives you access to the classified section. Most of my kit comes from this source. It is (in my opinion) the best place to buy used astro kit. HTH, David

Hi Treveor. An 831. The somewhat chunky 3D printed solution utilised a set of big guide scope rings that were idle. The alternative is from the plumbing shop. Munsen rings. Steel pipe clamps with loads of rubber padding included. A fraction of the cost of conventional scope rings. I think I bought mine (76-80mm fit) from here.... https://www.jtmplumbing.co.uk/pipe-fittings-c433/copper-chrome-brass-saddles-brackets-c239 David.

Pics please🙏 I won't be home until after sunset😢

Unfortunately astroboot no longer sell to the UK market. Something to do with the b... word that we can't mention.

Assuming you are restricted to using small part of the garden, your horizon is fixed. Take basically any mount (altaz or EQ) that has an angle marked and put a finder on there. Alternatively use a digital angle gauge if you have one. Just point it around the roof lines and you get an indication of horizon in various directions. I did something along these lines when thinknig about the site for my observatory. A valid thing with houses. But not valid in the long term if there are trees🤔 HTH, David.

Strange coincidence! I recently bought an old Swift - ringless. Last time I wanted awkward rings a few years ago, I got them from Geremany. But that is not so easy now. When I looked to buy rings from FLO, delivery was a few days, but before I hit the buy button, it moved out. Now 3-4 months. My solution is to 3D print packing pieces/adapters to fit inside bigger guide scope rings that I have. A work still in progress I can post photos later today. Happy to help with printing if you have some larger rings available. David.

Apologies if I am stealing another thread - but I couldn't find anything. The 2023 PAS is on Saturday March 11th. For me an obvious choice as it is a simple cross country drive. Anyone else going? https://practicalastroshow.com/

Hello and welcome to SGL. Collimation is still way off. The key word from @Mr Spock is 'concentric' All of the circles in your views must be concentric. Once you get the cheshire, it will be easy. Did you buy from an astro retailer? Any astro retailer will be happy to show you collimation if you take the scope back into the shop. We can offer advice, or pointers to videos. But 5 minutes hands on is (in my opinion anyway) much better.