Carbon Brush

I have no idea what goes on inside the the EAF. However, if we believe the circuit works and does no harm.... You could fit a 5K variable resistor in place of the 4K7 fixed and see what happens. I suspect at some point the focus will switch between fast and slow, rather than produce a variable speed. But am happy to be proved wrong! HTH, David.

Is that all? I assume you are still building your collection😂

The limited TV broadcast (dash & security cameras) footage gave me the impression of space junk on the way down, rather than meteor material. That is an uneducated assessment based on colour, speed and brightness changes. More knowledgeable/informed opinions welcome!

Absolutely! I have met quite a few members and every encounter has been a positive. A great crowd. Well there was one who would not answer the door when I went to collect a scope. I have to tell the story as it was still a positive. I knocked on the door and we exchanged a few words through the frosted glass about him having to isolate due to going into hospital imminently. This was when covid was still a big problem, but we were allowed out and about. The scope kit was placed on the back garden for me to inspect while he watched through through the patio door. Everything was in order so I loaded the car then phoned him. We had a great chat for quite a while before I returned home. Yes the SGL members are a great crowd.

My 'local club member' story has some similarity to @wookie1965 experience. I used to go to a society, having found them initially helpful. They identifed serious problems with my first reflector, a new OO scope. They were not too far away, they had a good lecture every month and their own scope collection. Sounds great, and initially it was good until...here are few examples..... I turned up for a lecture evening to find the door locked, but the place obviously occupied. I rang the bell. Someone came to let me in making some comment suggesting I was a lesser member due to not having a key. This is a key issued after taking training to use their in house scope unsupervised. Something I had not bothered to do. I failed to promptly renew membership. There was no email or postal reminder and I was a bit busy with house buy/sell/stress. About 3 months later when the dust had settled I realised my omission and put a cheque in the post. The secretary replied that membership was full and returned my cheque. They were capping membership at the capacity of the lecture room. Does every membeer attend every lecture I wonder??? I was told that I was on the waiting list and would hear from them in due course. That was 2007 and I am still waiting. I still have the letter somewhere. A little later I found there had been quite a few changes. Including electing a new chairman who didn't own a telescope and who had no interest in looking through one! Over the next months/years I was told by my spy on the inside that they had admitted quite a few new members. Including the wife of the non-telescope owning chairman! Where was my invitation I wondered? Lost in the post? Needless to say I am not especially interested in pursuing this particular closed community. These days I will talk about astronomy with anyone who will join in the conversation. I lend out kit to newcomers, or others who wonder about that scope type/mount/eyepiece.

My own take is that it is great for the 'plant and view' type of use. Opportunistic imaging without hassle. Easy and quick to set up on a night when cloud is expected in an hour or two. Very portable and I will no doubt include it when travelling to distant places. As an only scope - NO. Not unless you want to plant it outside and view a limited range of targets (suitable for the FOV) from indoors. Was it worth the £500+ - YES. Do I regret the spend - NO. I think the small number on sale used, compared to hundreds purchased, shows we have not yet worn off the novelty or found they are awful. Unless we are too embarrassed to admit our mistakes🤣

A new member asks a question. Several established members offered advice, assistance and further questions. Little realising the OP simply posted and went away. Apparently his last and only visit to SGL was to post the question. Why do we bother?

My two pennorth from an ill educated source😁 You have two pieces of glass with a very small air gap and very similar curvature. This means you have the conditions for producing Newtons rings. Ah but you need monochromatic light not daylight - I used to use a sodium light when measuring. Yes ordinarily monochrome light is essential. However, we are looking at coated glass. This is intended to let almost all the light through and not reflect. In practice it will not be 100% ideal - no lens coating will be. If the coating means a narrow band in the blue/purple part of the spectrum has much more reflection than other wavelengths, you won't notice at the eyepiece. If your refractor had poor performance at an interesting wavelength like Ha or OIII that would be a different matter. However, the reflected light, being narrow band, will allow Newtons rings to be seen in reflection. So nothing at all to bother about. The rings being circular and in the centre of the lens means the glass is mechanically well positioned. As the rings are in the same place every day, the lenses are not moving. Their colour means reflection is in an unimportant part of the spectrum. I have seen rings on a refractor. An old doublet, but I can't remember what it was. By pushing on the lens and squeezing things, the rings would come and go. Not recommended on an expensive frac unless you are going to ask a grown up to put it back into alignment for you😂 Look through and enjoy. David.

Do you have a meter to verify voltage? Links to the products you are considering?

I bought a Seestar late 2023. As a quick plant outside and start to get images, it is fantastic. Really good for those iffy view nights. However, it is far from a 'do everything' scope. Mainly due to the fixed FOV/magnification. While it 'does everything' it is best at nothing. For a quick no hassle setup and view Seestar is great. Though as an only scope - definitely not. Not yet tried, but I think it would be a good holiday scope. In holidays near the equator there was always the 'never seen before stuff of the southern sky. But what astro kit to take given everything else to carry in limited Kg of baggage - and the limited time. I have taken binos and done basic DSLR + long lens photos. I have no doubt if/when I go again, the Seestar will be in my case. It will provde a lot of happy memories for the Kg of baggage and hours spent outside. For the remainng 50 weeks of the year.... If I want photos then mixing camera and scope FL to obtain FOV to suit the object. As @Richard N can do. If I want planetary detail on Jupiter, or the moon, or look at close doubles, I reach for a MAK or long FL frac. If I want wide field views then a short FL frac or fast newt are good. It I want star trails it is a camera on a tripod.

Not a lot of regrets. Mainly because I am not that good at parting with kit! Often when buying the different/improved kit I hang on to the old for comparison. The comparison phase then turns into keeping the old for holiday/weekend away use. Then it may get loaned out to someone. Eventually my house has started to resemble an astronomy kit warehouse/showroom!

Gaffer tape and elastic bands to the rescue🤣

Yes a drawn out discussion. I took a look at the Talentcell specification and user manual (attached) and it will provide 14V on full charge. This is OK for the majority of mounts and accessories. The 5A capability is good for big mounts and off balance loads. The Skywatcher site was particularly useless at providing a manual - linking me to manuals for 5V powered products! However, Mr Google came to the rescue. https://www.manuals.co.uk/sky-watcher/star-adventurer-gti/manual Note that the table on page 2 indicates maximum supply 12.6V. Lower than the Talentcell delivery with decent charge. Current consumption is not given. But common sense says it will be easily within the Talentcell capability. Yet another case of Skywatcher providing sketchy and incomplete product specifications. not just electrical, their optical specs are just as vague. Yet we keep handing over hundreds of pounds for their kit? HTH, David. lf4100-user-manual.pdf

The short and poorly checked answer is that it should be OK. The correct (but not immediately helpful) answer follows. The Skywatcher user manual (and CE/UKCA approval documents) should state max/min voltage for correct operation. All these must be available from the importer (a legal requirement) if not supplied with the equipment. The Talentcell user manual (not a few bits of text on the amazon web site) should state the output voltage range in normal operation. Also their approval documents should contain this information. Ensure the upper end of voltage (at full charge) supplied does not exceed that allowed by Skywatcher. Very important! If the lower end falls below that allowed by Skywatcher, monitor voltage when in use and be prepared to end use early. Kenable are a well known cable manufacturer. The long answer is to identify the Kenable part number and check the spec on their web site. The cable CSA or resistance will be specified. That allows you to calculate exoected voltage drop. Provided it is small (which I expect) it can be ignored. All of the above is applicable to any mount, power supply and lead combination. Not just this enquiry. With the caveat that if a heavy off balance scope and big mount are involved, slew currents will be higher than expected. HTH, David.

Thanks @adyj1. The biggest 'wrongs' on any lithium charging are to charge to a higher voltage on each cell than specified, or to continue a charge current after charging is complete. See the various online clips of chinese ebikes and the like bursting into flame. Charging to overvoltage makes them into very good firelighters🔥 The argument that you have to charge in a short (few hours) for best life, rather than take your time, is still very much unsettled. I have used this cell (chemistry) type in an application where charging is at the whim of the weather - solar and wind. Access to the equipment for battery swap is extremely expensive (around £20K now) so I had to be confident of battery longevity. I think (fairly confident) that the pack used by the OP will have a good internal BMS (battery management system) and the charger is fixed voltage. If this is correct, then a charger offering the same voltage, but lower current delivery will not have any adverse effect. That is thinking about a small plug top or desktop power supply. Assuming the new charger is happy running in current limit for hours. Some are not! The test is to put an overload (car headlamp, brake light, etc) on the PSU output and watch. If the PSU struggles with a dim lamp, but desn't seriously overheat, you are OK. Some supplies overheat. Some shut down on overload and retry at intervals. Some require a mains on/off cycle to reset. Obviously all these are unsuitable. If you try a USB boost you need to know if the USB source is the power limit, or the PSU is the limit. Another can of worms to open! At the end of the day it is about understanding the original equipment and the replacement/additional parts you are looking to add. Oh yes - and measuring real world volts/amps. Not relying on the product label🤔 If you have the skill set to evaluate alternatives, fine. If you don't, stick to the original. But is the original charger that bulky? HTH, David.

@fireballxl5 Why not ask Tracer about options for the charger? Though the 4A standard unit isn't that big or heavy. Using a shorter mains lead (you need a US plug of course) loses some bulk and weight. Measure the off load voltage of your standard charger and look for something with the correct voltage and lower current rating. Provided it is a decent design, it will run in current limit without cooking or failing. You can check this out before leaving home. There is nothing wrong with charging at lower current for longer. It is just that Li is suitable for fast charge and most people want this! A lightweight 5V to 14V(?) boost regulator is another possibility. Again beware of the £1.99 offerings and check before leaving home. HTH, David.

Any of the reputable name power packs will be fine. May I suggest you buy from a specialistastro retailer? They are best placed to advise you on present nd future equipment and accessory choices. Try asking amazon customer services about additionasl eyepeices, battery life, mount options......

What sort of location are you viewing from? Light polluted city centre? Where will you store & use the scope? 3 flights of stairs to the back garden? Do you want to take a scope on a holiday flight? To me, these are the only arguments in favour of a 127Mak as a sole scope. They are good scopes, but..... +1 for @dweller25 and @PeterStudz suggestion. An 8" dob is very much a 'keeper' scope. It has the light gather for DSO and will take the magnification for planetary. Less convenient to carry than a 127Mak - but do you want views or portability? Speaking here as someone who owns or has owned reflectors in the 8" to 12" flavours, and Maks 90mm up to 150mm. Don't rush. Ask around. Try to have a hold of the scopes, and a look through if someone local has one, or you can go to a club. Enjoy the hobby. David.

If you want to go down the galvanised steel ventilation duct, you need to ask the right question. Do you manufacture spiral duct? Most ducting manufacturers have machinery for making rectangular duct, not circular. Circular duct is made from a steel strip with rolled edges - in a spiral. If you look at the ducting company web site, they may show sprial duct in their client example pages, or may list it in their capabilities. Having found a company, just turn up at the workshop (not front) door carrying folding money, or beer, or similar currency. These companies are not interested in making one short piece of duct. They are dealing with much bigger jobs. If they make spiral duct for sale to other installers, it tends to be in long pieces like 5 metres They may have an offcut on the way to the scrap skip, or they may be kind and make one for you during the tea break. HTH, David.

Just to add.... The general Skywatcher type dob benefits from a bit of interior darkening (flocking and/or paint) to reduce reflections, boosting contrast. HTH, David.

To bring up the faint stuff you need aperture. Or go to EEVA. What do you mean by inexpensive? Does the budget (and handling/storage) stretch to an 8" dob? This size is (in my view) a good compromise between aperture, cost and carrying.

Agree absolutely. Reading these discussions, there are some semi-related memories that I recall. Within our family we have a set of encyclopedia, published in the 1920s. There is no Pluto. The planets (and known distant objects) stop at Neptune! Around 2004 I attended a course by a local astro society. At the time the first named object beyond Pluto had been located. There was talk of maybe another one, or two. There are now rather more! When NASA planned to launch New Horizons to flyby Pluto, they thought they ought to take a closer look at the destination. In doing so they discovered more moons. The huge (compared to the other moons) Charon had only been known since 1978! More recently I read of someone in the UK being involved in constructing a solar system model. Planets on plinths with explanations, spread around a village. I forget the exact details. The Sun was about football size and Pluto a biro ball size about 3KM distant! Just how do you find similar gravitationally insignificant, tiny and dark objects? Off topic. I think if Alpha Centauri been included in the model, the plinth would have been in California!

I worked out that a train trip to London/Kensington would work out at near £100 and result in a very long day. Assuming the trains and underground were running. Then there is the difficulty of carrying the bargain 16" dob on the underground to get home🤣 PAS is my chosen spring show. By car at a fraction of the travel time and cost. If I can car share, the cost drops further. Show organsers and retailers take note. The UK is not centred on London. A glance at a map shows it to be in the bottom right hand corner😁

I have always bought additional dust caps. Usually taking advantage of buy now bargain prices if possible😁 As a proportion of the cost of a decent scope, or diagonal, or eyepeice, they are next to nothing. They are very useful for keeping crawling things, as well as dust out of scope parts. A temporary solution I have used is masking tape over an open end. Don't forget your full complement of caps can easily become depleted when long grass eats one in the dark🤣

Late into the discussion, and only a couple of photos to look at. But maybe relevant. Circuit designers sometimes omit over voltage suppression/protection components. Either they don't think about them, or a bean counter somewhere argues about bill of materials cost and the designer tries to save 10p. Then in the real world it is realised there are more failures than expected. If not warranty claims, they are loss of company image/status when they get known for unreliable product. Oh - maybe overvoltage or reverse voltage protection is a good idea after all. The 'extra' diode mentioned by @Trickysystems may be a 1N5401 (3A rated) diodes in series with the supply. Providing reverse voltage protection. The tiny 8 pin device U6 could well be a zener protection network. These are made by several companies and find their way onto USB ports. They would help on logic level RS232 ports. HTH, David.