Carbon Brush

I might buy a tent from Millets. Correction. That was until this report. Given this twaddle, can I trust them to supply any advice or product?

Another wedge to consider is the Lacerta wedge. Easily purchased from 365astronomy in the UK. No idea about your purchasing. There are several threads on SGL in the solar section about different makes of wedge and Brewster angle vs 90deg. At the end of the day everyone seems to have been happy with whatever (known astro name) kit they have bought. I have yet to see 'I wish I had bought Brand A instead of Brand B'.

We can all discuss these differences and appreciate how things change with latitude. But not everyone is like this. On holidays near the equator.... I have immediately noticed how late afternoon the sun descends almost vertically to the sea. No scraping the horizon! Darkness falls very quickly. The sun ascends on one side of island, climbs vertically overhead and descends on the other side of the island. None of the other (northern hemisphere) visitors I spoke to had noticed any of this. They just moved loungers to sun/shade as necessary. Again on a near equator holiday. Where are the recognisable (northern hemisphere) stars? Let me locate Polaris to get started. Drat it is scraping the horizon. No way can I make it out. Never mind. Look the other way (south) and enjoy the (never seen before) sights😁. Again I was on my own noticing this. It was an island with little light pollution. In Egypt on a night dive away from built up areas I remember orange skyglow from a town around 50 miles away. I also remember how it suddenly got very dark when the (near full) moon dropped behind a big hill. That has to be the measure of a clear sky. Again nobody else noticed. Apologies for the ramble.

My observatory build (2007/8) was my best astro spend. Power on, roof back, view. The scope is on the aligned mount and at near enough outside temperature. When cloud, rain or cold take their toll it takes very little time to park, close roof and lock up. OK a condensed scope and mount can benefit from a blast by a hair dryer. 5 minutes. But going back to this outside setting up for serious observing - no.

Yes away from the house. A west facing brick wall can be a good early evening radiator. Tumble drier, bathroom, kitchen or boiler vents are awful air disturbance devices. Yours or others nearby. Thermals fom a roof some distance away can be problem. Then of course if you or a neighbour are growing 'certain substances' in your loft that require lots of warmth and didn't invest in insulation🤣 I believe some such installations have been located by police helicopters using infra red cameras!

This is a good excuse to buy a second scope😁. Something completely different like a long FL refractor. If both scopes give poor views, blame the sky. Or maybe get a 3rd scope just to get another opinion? Seriously though. The sky quality does vary by location and sometimes by the hour. I have had 'bad' scopes that have fixed themselves a couple of hours later. I have also had scopes that worked great early on and apparently degraded later. Don't go jumping in and looking for problems until you have consistently seen the same problems (like collimation) a few times. Tube currents vary over seconds. Atmospheric turbulence varies by the second. Pinched optics change slowly with temperature. Collimation is permanently present. HTH, David.

You may be surprised to hear how many people have been confused by USA date format. 03/10/24. It that Oct 3rd? March 10th?

If a lithium cell is deep discharged for any reason,the charger will only allow a small current to flow. The actual values are determined by cell manufacturers and used by the equipment manufacturers. This is for your safety, and cell longevity. A further safety feature in a charger is a timer. If the cell is not fully charged after a few hours, the charger turns off. Often charge current is limited to only 50mA until the cell reaches 3V. In other words 20 hours to put 1Ah of charge in! As @Neil H says, grab a voltmeter and check the situation. Write down the cell voltage. If the cell is low, just recharge for a few hours. If you don't see recovery switch off for a few minutes and repeat. It can take several retries (timer above) to restore high current charging. Another useful cheap tool is one of the USB volt/ammeter boxes. You should see a low charge current that at some point changes to high, when cell voltage is high enough. These boxes are very handy for diagnosing dodgy charging cables! HTH, David.

But its also visible in the daytime sky almost as frequently. The post from @Paul M reminds me of a funny (I thought so) question I overheard from a nearby garden. It was nice morning, and plenty of folks were in their gardens. It happened to be a day when the moon was very visible in daylight. A nearby house had visitors with loud voices - or they conversing at opposite ends of the garden. I'm not sure.. Question on from one (mature/adult) visitor to another on the object in the sky 'Is that the moon?' Make of that what you will😁. Or are there other rocky looking big objects in the sky that I have missed all these years🤔

Thinking about a newt. A mirror at uniform temperature, whether 0C or 40C, has the same shape, and therefore consistent performance. A decent mirror has very low thermal expansion, which means cold edges and hot middle should have a small effect on shape. How much this matters depends on the temperature difference. It is all a matter of degrees. OK I'll get my coat. An eyepiece (even a jam jar size multi element) is small and low mass compared to a 10" or 12" mirror. Temperature difference from centre to edge is going to be small. So performance hit should be small. Cooling is going to be fairly quick. So by the time you have thought much about whether view it good, temperature has become stable. In 2011 I trialled a solution to the 'foggy eyepiece' and 'not enough pockets' problem. A fibreglass box (strong enough to stand on) containing large resistors and a fan on the aluminium plate. Power from a 12V supply. Just keep eyepieces in there when not in the scope I posted about it on SGL and there was zero interest!

A very good suggestion from @dweller25. I'm sure an experienced eye will identify the problems in two minutes. Given ten more minutes maybe even solve it. Absolutely. When tinkering with reflector scopes I used to be surprised at just how far an object has to be to achieve focus. Now I just accept it. Often a garden length is not enough. Unless you have a country estate🤣

You asked this question in January. It was answered. Are we missing something?

Looking at the BBC video - I assume it was the same incident - It seems he targetted the police helicopter!

For a definitive answer you need a consulting engineer who specialises in groundworks and foundation😁. In reality the size depends on the size/weight of the pier. If you make it 60cm deep, that is plenty for most purposes. As for diameter, that is a bit different. If you want a 'perfect no instability' pier, you don't want to be stamping your feet on it. Hence the idea of a narrow column. However, you are going to be standing on the ground near the pier. If you put down a bit of decking, floating over the pier, you isolate the pier from vibrations. My observatory has a one piece foundation and concrete pillar. Later the shed base was poured - leaving a gap to the pillar. When building my setup, there was much less information readily available. The lump below ground was almost 1 metre cube. With hindsight, more than required. I figured that once you start to dig, it is little effort to dig more. Concrete is not that expensive. A base that is too big juust gives you more excersize digging and costs a bit more sand & cement. Having already hired/borrowed the mixer. If the base is not good enough, you have to dig it out and start again. If the ground moves seasonally, or more slowly, it is not a big issue. Just visit your polar alignment occasionally. If ground moves slowly, your base was not deep enough. I'm sure others will be along with their experiences.

Going back to the original report, the worm is turning, which suggests clutch slip. Driving at high speed might overcome some of the slip. A good test is to remove the scope tube and just leave a flag (bit of paper) on the mount and see if it tracks. If all is well on light load, you have a slipping clutch. Skywatcher clutches are not the best in the world. If the clutch is slipping, tighten the nut by a small amount. Say 1/10 turn and see what happens. I would also get rid of the small (uknown origin) plug top PSU. Put a decent supply (like a Nevada) on there and you know you have a good supply. Explaining why an unknown and under-rated PSU is risking problems requires more than a one line answer🙂 HTH, David.

Adding to the good advice from @Cosmic Geoff. The rubber buttons are made with a conductive layer to bridge the PCB tracks below. The conductive area can become worn. Not all buttons fail together and a harder press can make them work. Hence Geoff's questions. If it looks like the conductive layer has failed, you can prove, and make a temporary repair, by rubbing a soft pencil on the button pad. Maybe a careful brush from a PCB repair pen (silver loaded conductive paint) might help. I have never tried it on a flexible keyboard application but it does work on PCB tracks. For cleaning I would use Isopropanol intended for electronics cleaning. This is 99% and more pure. The 'over the counter' cleaning agents often contain additives that can mask problems. For example, denatured alcohol (called methylated spirits over here) is in majority ethanol + methanol. However, to stop you being (very unwisely) tempted to drink the stuff, there are dye additives. These can leave deposits. HTH, David.

Not at all a daft question. In fact it is a question I asked myself when building my observatory. Yes scope type does matter. Certainly for visual use. Think of a long refractor looking near the zenith, the eyepiece is near the floor. Now a short tube MAK/SCT. The eyepiece does not move by much. Now put a big newtonian reflector on there and fetch a step ladder to reach the eyepiece! Is your current scope a keeper? Might you be tempted to try other scopes? Yes of course you will. A pier purely for AP can be any height - provided it clears fences, etc. The inconvenience of kneeling, or climbing a ladder to fiddle around is not that often. When building my pier, I wanted to ensure the pier was low enough for a 10" reflector to sit on top of a mount (bigger than EQ5 that I would probably buy) and the roof slide over. I built a bit low, meaning I could add a spacer to increase height if necessary. Studs protruding from the pier top to a plate gave height adjustment. My Alter D6 mount with Intes MN78 on top, parked horizontally, does clear the roof. A 25/30cm step stool is a good idea for viewing near the zenith. Have a try out with a tripod based mount and any scopes you can borrow. That will give you a good idea of a target height. Good luck with the research, David.

Hello and welcome to SGL. A good move learning on a free scope. Unfortunately some spend lots of money buying used stuff that needs lots of money throwing at it. First comment. In daylight look at a distant object. Building, tree on horizon, TV aerail. Anything a long way off. Locate the object using the main scope. Then move the finder to centre the object. I can't see the detail in your photo. But usally the finder tube has adjustment. sometimes the base as well. Keep the comments/questions coming and enjoy the journey.

I thought I ought to view the video. Surpisingly little is said about what appears to be a sliver of something dancing around the sky up to 1 degree away from the bright sun partly obscured by clouds. I assume this is one (erroneously left visible) component of the many required to create the illusion that is being created for our amazement and wonderment. To move a large object at this rate it has to be powered by technology and forces beyond our comprehension. Apologies if this is moving the thread on to a different subject. I assume the boring folks on this forum will use IS lenses, internal reflections, etc as an excuse.🤣

Difficult from a photo but my thinking is chemical residue or coating damage. Good call from @Don Pensack on acetone. You might also try isopropanol. My experience of coating damage has been worn areas resulting from someone being over enthusiastic, many times, with a cleaning cloth on binoculars. Another (actually two people) was spectacle lenses losing coating after repeated cleaning using isopropanol. An odd clean won't do harm. The specs lens developed cracks in the coating and got to the point where a finger nail could flake off areas. For reference the specs came from 'should have gone to'. Your photo doesn't look like either of the above. It loks to be well defined round areas. So I'm hoping a bit of the right chemical will do the trick. Let us know how it goes.

Agree absolutely with @Stu1smartcookie Around 15/16 years ago I had set up a really good tracking mount in the observatory. Visually it was a great setup and I spent many cold nights there. I decided to try out this astrophoto lark. At the time astro cameras were less capable and more expensive (in real terms). I opted for a DSLR. It all went very well. Except... Spending all night getting poor images was very frustrating and took away enjoying the hobby. Standing around waiting for the shutter to close and glancing up to make sure the sky was still there was boring. Automating so I could sit indoors was going to take a lot more organising. My solution was to plant a second scope outside and just look. I could change magnification or target object every minute if I wanted. I could even swap scopes on the mount given 5 minutes. Pop back into the observatory every so often to mak sure everything was still running. Move forward to 2024. Plant the Seestar outside and leave it to get on with building pictures. Use a second scope on any mount to enjoy the views. The hobby is again enjoyable. Except.....The clouds and increased light pollution.

Not sure if I'm misunderstanding something in the previous couple of posts. But here goes. The important thing is to have a power suppy that delivers 12V at more amps than your combined loads. The individual items look after themselves for current. A non astro example. On cold morning, your car start motor may demand 400-500 amps from the battery. When parked with headlights on, the bulbs combined may demand 20 amps from the battery. When you turn on an interior light, it may draw 0.5 amps from the battery. Everything looks after itself, regardless of the very high current capability of the battery. Bottom line. If you buy a 12V 30A power supply to run a small mount, you won't damage anything. It is the 12V that is the important number. HTH, David.

A note on dew heaters. If you have a heater that takes say 1A, and run the controller on 50%, it may appear on a meter to take 0.5A. But that is because the meter displays an average. The reality is that the heater is taking 1A and being turned on/off with a 50% duty cycle. In this case the full 1A is 'seen' by the lithium pack protection and you get a trip when the draw appears to be below the threshold. If you have a bench PSU, it may cope, or it may droop causing mount (power failure) trip. It all depends on the PSU construction and dew control timing. If you have a lead acid battery, the old fashioned wire fuse in general handles the high current on/off without problem. HTH, David.

A bit late but the answer comes if you delve into the usage details (not just headline information) on the Celestron web site. The key phrase....The PowerTank Lithium LT and PowerTank Lithium models have a circuit breaker that will shut the battery off if the power draw exceeds three amps or 36 watts. Note they do not specify an overload/time characteristic. so you have to assume instant shut off. If you run a lead acid battery, it may have a 10A or larger fuse that that a time/current lag. In other words an off balance mount, or extra dew heaters, or inrush from a mount computer/camera are more likely to trip a lithium power bank. This is a good start page. https://www.celestron.com/blogs/knowledgebase/the-ultimate-telescope-battery-guide-getting-to-know-celestron-powertank-and-powertank-lithium HTH, David.

I have used Hyperions in all FL available. To me the big things were long eye relief and (certainly some years back) a really good FOV for the ££ spent. The ability to use them in 1.25" or 2" barrels was useful. Then of course they can have a camera hang on the front. Actually this was the only way I could get a Coronado PST to interface with my DSLR - again a long time back. I probably used them more in an F8 scope than anything else and was always happy with the views. Yes the FT rings are nice to have, but not essential. The rings are though low cost so for trying that different magnification.