Carbon Brush

A company based in Worksop have featured in a couple of SGL threads. From what I recall they are flexible about designs, features, etc. http://www.shedshedsheds.co.uk/portfolio-item/home-observatory/

I think many of the above posts have nicely demonstrated how 'specmanship' on sales flyers does not always match up to reality. How do we tell the difference between the good and unsuitable if we are non technical? Saying buy Bloggs, or Smith branded and avoid Jones brands works today, but not next year when models have changed. You need a handful of car bulbs, a few bits of wire and a voltmeter. Nothing advanced. A car sidelight is about 5W/6W. That is 0.5A on a 12V supply. Brake or indicator lights are 21W, or 1.75A. Headlamps vary but think of 55W usually, or about 4.5A. Measure the powerpack voltage on zero load. Then measure it on assorted lamp loads. If it drops by more than 1V between no load and a brake light, it is not suitable. If it drops below 12V on a headlight, it may cause issues when slewing a big scope. A small powerpack might shut down on headlamp bulb inrush. nothing unexpected here. If it provides 16V on no load, read the specification for the camera & mount before connecting! It could get expensive! You next test involves a clock. Read the amp hour rating from the powerpack. Connect a number of bulbs to discharge the powerpack in 3 to 5 hours. Set it going and monitor the voltage at intervals. For example a 10Ah pack should power a 1.75A brake light for 10/1.75 = 5.7 hours. Fine at room temperature. Now repeat the test at 3-4C. Put the powerpack in your fridge and run the test again. Do not try this test at -18C in your freezer. Lithium cells don't work this cold and you can cause damage. Lithium is fine to freezing point-ish and perfrms almost as well as at room temperature. As an aside, if you did this test using a lead acid battery, you would see a significant performance dip in the cold. You can see I have avoided having to know anything about cell chemistry, internal protection circuits, regulators, etc. The test equipment is nothing more than any of us have kicking around the house or garage. The results are produced in daylight and give you the confidence your powerpack won't let you down half way through imaging. More important. You know the powerpack is not risking wrecking your £1000 mount or camera. HTH, David.

Not antiquity, but a long time ago. A relative told me that in his childhood he saw light shining through a window to put a bright rectangle on a house interior wall. It moved slowly and there was no sound. The angle from window to wall meant it was coming from the sky. This was probably 1910 -1920. The location was Sheffield. He was convinced it was a UFO. Yes WW1 time it may have been a searchlight from a Zeppelin - did they have these? Sheffield steelworks were definitely targetted in WW2. However, he did not mention others seeing it, or any newspaper reports. I know that a Zeppelin was sighted by multiple witnesses by natural light (and the story documented) near Retford, about 20 miles east of Sheffield. This was one night in WW1. No light involved. So this is a possibility. However, now there are huge numbers of doorbell cameras, vehicle dashcams, security cameras and more that include some sky. We see in the media these when there has been a decent meteor. Add to this the astro community who are running all sky or wide angle meteor cameras. So where are the ET/UFO sightings?

On other mounts, I have fitted cut down bolts. The new lengths being only a couple of millimetres longer than necessary for my latitude. Hacksaw to just over length, leaving a couple of nuts on the thread to hold the bolt in a vice, and form the thread after sawing. A file or gentle work on a bench ginder will smooth any raggy end of thread. You can take a spanner or allen key to adjust. This also means you can fit decent bolts, rather than those made from stale cheese that manufacturers fitted a few years back. If you take the mount on holiday, either make different bolts to suit the new latitude, or refit the originals. HTH, David.

Good morning and welcome to SGL. If we are going to be able to help, you need to provide some more information. Is this new setup? A secondhand setup? Recent fault? Like this from opening the box? How are you powering the quipment? Any photos of the screen showing error messages would be helpful.

There is an HEQ5 with belt in the classifieds. I have no affiliation, recommendation or knowledge of the item or seller. Just seen it😁

Those in the know usually say an EQ5 is pushing things for photography. An EQ3 is undersized. I'm going on what I have seen posted. Never done photos on EQ3 and not owned one for many years. My thought would be to look for a bigger 2nd hand goto mount/tripod to get things moving straight away. HTH, David.

Hi John. Thanks for your comment. Yes it is always a good rally. Viewed by many as the best for 100 or more miles around. No HF (or other) stations on the day as it is all hands to the pumps car parking, manning club stalls, looking after other traders, etc. For HF contact at other times, there are a couple of members who are into CW contests. David.

There is also and indoor trader area, mostly run by the radio club. The first image shows a table containing lithium battery packs 1850 based, 5P 4S. These are removed from life critical medical equipment, removed on the basis if date. You are getting known name cells with (all but) 100% life remaining in the cells. Not dodgy unamed product. Then there are 12V lead acid batteries. Removed from ship emergency lighting on the basis of time. In reality they are again near enough 100% of new capacity. The final pic is a general view of the internal sales area. Early in the morning the outdoor traders will arrive. I will be too busy to be posting pics.

Update saturday evening. I was at the site today to help with setting up. Preparations are well underway. Importantly the outdoor sales area and the car parking are firm. not boggy or waterlogged. The forecast is for much less rain than today. The photo shows part of the trader area.

Thought this drone pic from last year might help get an idea of what is there.

Why am I posting this? There is a significant overlap of people between astronomy & amateur radio. Quite a few have a foot in both camps. Why post here? I couldn't find a better place on the forum. Mods please move if you have a better idea. An amateur radio rally is rather like a car boot sale, with some retailers added on the end. It covers mainly radio & electronics stuff. However, there is often astronomy related stuff on sale. Last year at this rally I picked up a scope tripod and missed another tripod while thinking. I know that the club, who are hosting the event, have on their stall some 13.8V supplies, like the Nevada and others we use. There are lots of 12V 4A switchers - I donated them. Quite a few other power supplies as well. I have seen a big box containing a few hundred DC connectors, the size we use on astro kit. A significant amount of items for sale are relevant to the DIY astronomer. The club is fortunate to have the exclusive use of buildings associated with the long gone RAF Sandtoft. Members have been experimenting with microwave comms, and are working on EME (bouncing radio signals off the moon) using a 3M dia dish. Hmm, how to track??. A few days ago they were listening in to chat from the ISS to students in Canada. It was an orbit just sneaking over the horizon for a few minutes. Around 5 years ago members trialled light wave (modulated LED) comms over tens of miles. At least two members own their own scope, and I usually leave something there for other members. Lots happens. As amateur radio is in decline, there is significant interest in other 'technology' based activity. The entry cost is £5. I recommend getting there at the start. These events tend to go off with a bang and by 1pm people are packing stalls away. Parking is on site. Unless it gets really busy, then there is overflow at the trolley bus museum a couple of hundred yards up the road. Getting there.....http://g0ghk.com/home/visit/ If you don't fancy the road trip and have a winged alternative, Sandtoft (friendly GA airfield) is walking distance. I will be there helping out and look forward to seeing SGL faces. David.

Is it possible the previous owner used a thread stiffening (or lubricating) compound but chose poorly? I have seen corrosion on copper PCB tracks, ali & steel fixings, from various causes in my electronics work. Anything from the wrong soldering flux, to mucky water, to rat urine, to corrosive food etching PCB tracks! It must have been a strong curry🤣

I'm in the high altitude balloon camp. Shiny objects are visible at great distance. As a young child I remember being told about the 'Echo' balloons. The passes being notified in a daily newspaper. I went outside at the right time and sure enough a slow moving 'star' was there. These were 30-40M diameter in 1000KM(?) orbits. Something this size and shiny in the upper atmosphere would surely be daylight visible. Apparent motion being entirely determined by the wind at altitude.

Is this why the 70mm is out of stock at FLO right now? Yes I'm thinking much the same for a 12" dob that I often loan out. Maybe use the 70mm frac as a finder? Do I understand this correctly? If the software is free and unrestricted, then it is only a matter of time before someone starts offering their own dock. For example a phone holder & cheap diagonal and a bit of 3D print would make a 'pirate' dock. A lot of bother for an individual. But having seen folks spends weeks avoiding spending a couple of quid....

The currently accepted age for the universe may not be correct. Only 100 years ago the 'wisdom' said our galaxy was everything. Only 50 something years ago the little green men (AKA pulsars) were discovered Only 30 something years ago explanets were a theoretical concept not yet seen. Shortly after it was thought by some scientists evidence for life on Mars had been found on a meteorite.

If you want to freeze anything quickly.... There are aerosol based circuit freezers for electronic circuits. Easily taking things down to -25C, some claim -40C. Here is one example of the many available.... https://www.rapidonline.com/kontakt-chemie-33168-aa-freeze-75-circuit-freezer-200ml-87-0665 Then there are plumbing pipe freezer products. HTH, David.

Your first task is to define the power requirements. How much is on 12V? Dew heater go from eyepiece size to 12" OTA. Does anything need 240V? etc. A laptop may be a power miser, or a power guzzler!

Sorry to drift off topic. Having seen various electrical equipment with FAKE mains fuses - HRC fuses that aren't. Then mains 'fuses' made from thin PCB tracks. Many other dangerous build practices that the man in the street doesn't know how to find, I don't trust them. Once I queried a mains cable they told me was correct and sent me the certificate to prove it. Actually they sent me an extract of the standard that proved they had used the wrong cable! I was once asked to look at a Segway copy type of machine that was having battery problems. It was stuffed full of lithium cells - about 10 laptops worth. It had been air freighted from China without air transport approval on the battery pack. Yes if we are daft enough to buy drill bits that struggle on stale cheese it is our fault. But often the fake materials and shoddy construction are not detected early enough. E scooters bursting into flames while charging for example? Back on topic. Yes hopefully plastic will filter short UV.

Yes an interesting thought. It is well known there is an association with catarcts and UV. I once saw a TV programme about people who lived in a high mountain region (sorry I forget the who and where details). The important thing is they had a really high incidence of cataracts, blamed by the professionals on increased UV at altitude. We all use 'white' lights now that are often derived from shhorter, ultra violet wavelengths. There are basically two ways to make a white non-filament light. The first is to build it from separate red/green/blue LED emitters and balance the colours. The second is to shine UV at phosphors. The phosphors convert the short wavelength UV to longer wavelengths that we can see. A technique used in fluorescent tubes and LEDs. But how much UV (invisible but harmful) gets through? Spectacles for screen users, cutting down UV, are available from many sources. From branded stuff to the untested and uncertifed stuff from the landfill generating country to the east. Looking forward to someone more knowledgeable tham me (which should be easy) contributing.

I looked at this a few years ago. Not all dessicant bags are created equal! My first thought was recycling in a conventional oven. This method is only financially viable if you are going to put lots of bags in the oven. A microwave at first sight looks a good solution. It acts on the water so limits to 100C. So you think. If the bag contents absorb microwave energy, you can have very high temperature in the bag. In other words don't walk away. things can go bang or catch fire. Maybe not on the spectactular level of placing ali foil trays in there, but you get the idea. For example some crockery absorbs microwaves, others don't. You see this when warming liquid and the container can remain cold, or can heat more than the liquid! I did not have (one of these new fangled) air fryers at the time I looked. It sounds like a good idea. A couple of litres of temperature controlled environment. On the list to try for the next drying session. Some dessicants can absorb a lot of water, some very little. The idea of a new dry weight marked on the bag is good. But what is dry weight? A new bag from the factory in a sealed poly bag can be assumed to be dry. A useful looking bag removed from something shipped to you has of course been exposed to indeterminate moisture before delivery. Then not all bags contain indicating pellets. When should I swap? The final hurdle is that the adhesive to seal the bag, and the bag material may not be suited to high temperature. Glue can melt and bag fibres break down. So yes it can be done but it is not a 'one size fits all' solution. HTH, David.

Having read that you have owned the scope from new, my advice on swapping out the transformer may have been hasty. The issue with old equipment is that you often don't know if someone has left it outside in all weathers, or attempted their own repairs and modifications. You can see where I am coming from. If you have had the scope from new, stored it sensibly and not repurposed the transformer, or modified wiring, you should be fine. I will give you an update on the stuff I have when I have negotiated the depths of the garage.

On the exterior wood protection. My 2007 build shiplap shed based observatory still has good walls. Tanalised (treated) wood was used. Since then I have been out with the cuprinol a few times. When assembling, be generous with the cuprinol (or whatever) on areas you can't get to afterwards. For example shiplap that is fastened to a batten. Or timber that is at the bottom. The pent roof needed quite a bit of additional timber. If starting again I would make a frame non-flat roof for rigidity. The original floor joists rotted about 10 years in. They were sitting on the concrete base. I replaced them by pressure treated 3" fence posts. Jacking the shed to avoid having to remove the contents & dismantle. Ask me in a few years how they have lasted. But I can jack it again. Like you I used a garage door opener. Excellent choice😁. The roof covering is pond liner - not roofing felt. Still good 2007 - 2023. While building consider putting thin vertical wires in the walls. Eventually linked to your alarm. When Burglar Bill tries to pry off planks to gain entry a wire breaks and you get lights and bells. Other security arrangements can be made later in the build. Following with interest. David.

The TAL motorised mounts had a 240V/12V transformer. The 'clock' or RA drive being synchronous motor. That is locked to 50Hz mains. Whether the transformer insulation is still good 30 years on is debatable. Of course in a modern house you have RCD protection...When did you last test it? I would replace the transformer by something new, or if wanting to retain authenticity, put a known good isolating transformer before the old TAL transformer. Again losing originality, yu can easily replace the 12V connectors by almost anything. XLR would be a good choice. Somewhere in the depths of my garage I have a TAL motorised mount. I will try to take a look (not before tomorrow evening though) and see if anything about the plugs looks compatible with modern stuff. Congratulations on the scope. If it has been looked after, it will give very good results. Mechanically and optically they are good. HTH, David.

I have used bar stool covers, like those described. Also been known to 3D print covers, spacer blocks, etc. When making covers for tubes bigger than my 3D printer, it was in pie slice manner & glue together. The finished items looked better than they sound😁