EarthLife

There's a total lack of science on TV these days, so any that might pop up should be encouraged I think.

As for the secrets of the universe, any advanced lifeforms out there with any intelligence will I'm sure be making sure their presence remains unknown !  Do we jump into a croc/ally infested river for a quick dip, or even just make your presence known to them, or wave hello to that group of hungry lions just over there ?  I'm guessing most wouldn't ? .. true knowledge has it's uses from time to time  

On 01/08/2023 at 03:15, curtisca17 said:

Yes, one can put a band aid on a bad design to get it working, but there is no free lunch.  A boost converter will give the voltage needed but will not be able to do it for the rated capacity.  So, for instance, you are paying for 72Wh at 12V but only getting, say 55Wh.  I don't consider that fair advertising. 

I never said it was a good solution

Just an attempt to make something of an already unsuitable situation really. If nothing else it helps teach them a 'little' about electronics.

Whoever said the human race was logical? .. Dr. Gillian Taylor

The easy solution to this problem is to use a boost regulator on the 12V output, something like this will give a couple of amps capability .. https://www.ebay.co.uk/itm/374835259124

You can get higher current/power units from places like AliExpress etc if you want more output current capability.

You will get more than 12V output from the boost regulator/converter, you simply adjust/set it to say something like 13.5V or 14V, which is perfectly fine. Once set you will have a constant regulated DC supply for whatever you want. Just try not to drain the power banks battery too much as some battery types don't always recover too well from being over discharged.

The way it's normally done on say a car is to use an IR LED and monitor the reflected/refracted light in the window screens glass, if it changes then you have water on the outside of the glass (due to blobs of water changing the reflection/refraction direction). It's very simple and reliable.

https://cecas.clemson.edu/cvel/auto/sensors/rain-sensor.html

But to stop copper from corroding just coat it with something like conformal PCB coating or pot it in silicon sealant (local DIY store) etc ?

7 minutes ago, jetstream said:

I'm in Canada and hate light blowing around the tube. I also do the focuser drawtube etc. This paint has actual smoke in it and was recommended by a retired chemist who now builds scopes. It works.

https://www.krylon.com/en/products/specialty/camouflage-paint#accordion-cee546f66e-item-9b5520e9a3

Amazing how they get that paint to create the camo effect

Amazon UK sell it it seems, though £74 a can ..

https://www.amazon.co.uk/Krylon-K02728007-Fusion-Spray-Paint/dp/B07LFRWLV8

1 hour ago, jetstream said:

In my case I used a special paint to paint the interior of the tube and flocked opposite the focuser. The secondary edge is super important to do and I used paint. When you look down the tube, anything that appears shiny should be painted flat black, including the tops of the secondary adjustment screws.

I wonder what "special paint" you use ?

I was thinking about using this "black hole" paint ..

https://www.stardustcolors.co.uk/bodywork-matt-paints-and-topcoats/1581-blackest-black-extreme-black-paint.html

Quite expensive but it's a one off thing to do.

One way is to have a 12V lead acid battery as your supply, keep a charger (constant voltage PSU etc) attached to it (and powered) that will maintain a constant 13.5V at the battery terminals (lead acid maintenance voltage).

Yes the 12V outputs from the PC PSU's I've seen and used are not regulated, it's the main 5V or 3V output that's regulated, the other voltage outputs will bop up and down as they please.

And yes adding a high capacitance (low ESR) at the far end (the load) can certainly help as well with noisy loads like motors. The electronics in these consumer type scope mounts are very cheaply made, they are most definitely not over engineered etc, they can be very picky and have little to no protection against certain conditions.

Get yourself a proper 12V to 14V PSU that is regulated and can handle at least twice the peak current (it will last longer if you do).

17 minutes ago, AstroKeith said:

The next component I'd worry about is U1 on the underside. I think its a 12V to 5V regulator, so would have been exposed to the full -12V.

As it's a short you have, checking out the circuit with a multimeter won't help I'm afraid. The 12V is likely to go to about 20 places, and anyone could be the short. The meter won't say which.

Well you can sometimes find the short circuit by measuring the milli-volts across two power pins on each chip with your meter with a current limiting power supply connected to the PCB. If a chip is the possible culprit then you'll get almost zero mV across it's power pins, where as on the other chips you may well have a few mV's on them, but that can depend on knowing the routing of the power track(s). It works due to PCB tracks having resistance.

You can also find a short on a PCB with the same current limited power supply connected by using a thermal imaging camera (if you're lucky enough to have one), it can be quite magical when you see the PCB track temperatures, the shorted chip might also show up as being a bit hot.

But anyway, whilst you have it apart, solder a nice fat reverse biased diode across the power input connector - it will save the boards if you do it again.

36 minutes ago, alacant said:

Why do I only get it with SW mounts though?

Without knowing all the technical details of your mounts and different power supplies and how you have the systems wired up etc it's impossible to say.

Do your other mounts have any possible electrical pathway to ground ?

Do the internal PCB's have there negatives connected to the mounts metal work ?

Lots of other things to know before anyone can give you that answer.

Very few switch mode power supplies (SMPS) have the output DC connected to Earth (helps prevent earth loops for one) which is why you often get a tingle, it happens with certified SMPS as well as cheap chinese ones. As has been said it's due to leakage, you get it both outdoors and indoors and is caused by the transformers coil-to-coil capacitance and the Y-Capacitor (the little capacitor that goes from the mains side to the output side).

The Y-Capacitor is there to help reduce EMI (electrical interference emissions), which to be honest is a feature of class 2 SMPS's that I find a little scary because it's a possible failure path directly from the dangerous mains circuit straight to the low voltage output.

The trouble with using any SMPS (or even linear power supplies) outdoors is you can very easily have dampness and/or condensation on the supplies PCB etc, this can easily cross the mains to low voltage output circuit (say across the HF transformer pads), especially at night. If that happens then your in danger !

It's much better to keep all outdoor voltages to a low'ish level (say 48V AC or DC and lower), that just means using either a battery system or running a low voltage supply from indoors to outdoors which then you regulate/step down at the mount to suit your needs.

10 minutes ago, markse68 said:

You edited your post before I could find the Carl Sagan quote

"I have a foreboding of an America in my children’s or grandchildren’s time—when the United States is a service and information economy; when nearly all the key manufacturing industries have slipped away to other countries; when awesome technological powers are in the hands of a very few, and no one representing the public interest can even grasp the issues; when the people have lost the ability to set their own agendas or knowledgeably question those in authority; when, clutching our crystals and nervously consulting our horoscopes, our critical faculties in decline, unable to distinguish between what feels good and what’s true, we slide, almost without noticing, back into superstition and darkness.”

oh sorry, I thought I'd remove the last bit I wrote as didn't really want to go down that route.

I liked Carl enormously !!  we need more like him.

39 minutes ago, markse68 said:

it's interesting and convenient that we only can sense 1 octave of visible light isn't it. Would get quite confusing if it were more. When I look at a deep red led like those new tail lights on posh cars, I see a bit of blueness to the red

Mark

When you look at the spectral curve of light that rains down through our atmosphere from our cosy star, it kind of lines up with the spectral curve of our eye sight, I highly suspect our eyes evolved to only detect what light is available in plentiful supply.

Any alien life forms wizzing around the other stars out there would I guess have eye sights with a spectral response that matches up with the available light coming from there own suns that make it through their particular atmospheres. This could mean that the little aliens would most likely have IR vision if their sun is a red dwarf, etc.

Life is extremely clever, and extremely resourceful !  a mystery for sure.

23 minutes ago, ollypenrice said:

So... I realize that it's possible that nobody has proven that our sensory experiences are the same.  However, I also know that there are countless examples of shared responses to shared sensory experiences. Certain colours clash. Having your fingernails torn out is horrible. Middle C played where it wasn't meant to be will sound wrong. 'Out of tune' makes sense. Chocolate and onions don't go together. This list could run to millions of examples.  Are we to believe, therefore, that by some remarkable conincidence, the relationships between these non-shared experiences are consistently unaffected by their not being common? Yes, you can argue this but - be honest - are you not flying a kite in doing so? Does it not make a lot more sense to suppose that, in our genetically similar bodies, we have highly comparable responses to identical outside stimulii?

Test yourself. A peer reviewed paper is set to appear, saying that it contains a clear answer as to whether or not your red is more or less someone else's red. You have a chance to place a bit on the outcome. Do you really bet on the the side that says we all have significantly different reds? I don't believe you will and I do believe that, if you do, I will take your money.

What's being said is that we have no way of communicating with each other on how we each actually perceive certain facets of our sensory input, such as colour, we simply don't have the ability to communicate that kind of information, at least no way that we currently know of.

It highlights just one of the limitations of our ability to learn and/or comprehend the place we appear to exist within, our own existence etc, which can be frustrating, very much so to some, not at all to others, to some the mystery is the best bit of it all.

Even with our attempt at copying the way the brain works (extremely basic artificial software neurons and their connections) can and does create totally different outputs from the network when all neural biases and connection weights are similar (all network values are slightly different), the smallest difference in those values (with same wiring) can and does produce totally different signal propagations and output results.

6 minutes ago, saac said:

We can now visualise and map individual neurons in the brain firing when triggered by external stimuli.  Comparisons would show whether it is the same group of neurons that are responding to colour stimuli. Common pathways would suggest a shared response.

It might well be a group of neurons and connections that are triggered in the same rough areas, but those neurons can be totally wired differently in each of us, and so create a very different experience. If we were all wired the same, we'd be identical drones.

Some people love pain, some people can't cope with pain, some people have no pain/touch sense at all.

8 minutes ago, saac said:

I've came across that before but I don't agree with it. Humans have 3 types of cone cells (L,M and S) and within each are found particular proteins (opsin) - proteins of one type being expressed more in each type of photoreceptor.  Each particular protein absorbs the energy of the photon with a greater efficiency of absorption aligned to specific frequencies of light corresponding to 420, 534 and 564 nm peak.  Now baring mutation, that setup is the same in each of us. The same proteins, the same favoured excitation frequency and the same efficiency of absorption.  The response is a biochemical reaction known as the phototransduction (production of ATP  to power the sodium -potassium pump) ultimately producing the electrical impulse which is detected by the brain.  This is the biochemical response of the retinal cells and it has the same mechanism in every human. It is in effect our instrument response, there is no other way it can function.  Appropriately stimulated therefore with a wavelength of light of 534 nm, each of the 3 separate proteins will produce a response, however one particular protein produces a greater proportional response to that frequency. That mode of response, the same in every human, is the response that we label green.  I'm not sure how else it could be interpreted for there is no other mechanism to produce that response. 

Jim 

I don't think it's the physical method of colour detection/sense that's in doubt, it's more how we each perceive the colours and the various combinations of them once the signals reach the brain.

I don't think life is random in any way shape or form, it's mind blowingly complex, surpasses any and all tech that we could ever create, and reproduces at the drop of a hat. Yes random mutations do happen, but life appears to have a very definite driving force behind it. Apart from where the universe really came from or what it really is, life has to be the most strangest part of it all - that we know of. And it's a totally natural part/evolution of the universe, else there would be no life. All it seems to need is a suitable environment to exist in, given that it seems to propagate like nothing we know.

Although fire is much the same, it will spread and propagate given the chance to do so. Stars are a good example for that.

45 minutes ago, vlaiv said:

Take "warmth" for example. Blue is cold color and red is warm color.

Nothing about cold or warm is related to perception of color - it is rather related to matching of colors. We say that red is warm because fire is red and sunshine is (reddish - on sunset for example), while blue is water and ice and thus is associated with cold.

We just took names of perception phenomena (we similarly can't say if we experience cold or warmth in the same way) and made a relation between them.

Yes we simply try and associate 'stuff'. In reality a big blue star is hotter than a little red star. Metal turns red before turning blue/white hot, much like a flame, a blue flame is much hotter than a red/yellow flame, although a methanol flame is totally invisible to the human eye yet would turn you a crispy black.

I guess you could take taste and smell as maybe an example of how we can each experience a sense differently. The smell and taste of garlic to me is flipping awful, yet others say it's wonderfully lovely.

I'm not saying we do each experience colour in our own way, but it's not something we can actually test is it ?  not sure how science could do such a test.

11 minutes ago, ollypenrice said:

Would you say that about the musical scale, though? 

Olly

Personally I'd find it hard to imagine how'd we sense audio frequencies differently I think. Strange isn't it.

2 minutes ago, ollypenrice said:

It is also hard to imagine how the visual arts would work without a common experience.

It wouldn't matter, because red paint would look like red light, green paint would look like green light to a particular artist, no matter how differently we each visualise colour.