Xilman

Just now, saac said:

I think explaining to children age 10 that the consequences of the half integer spin property of fermions prevents Earth's collapse against it's gravitational field would be somewhat questionable and the motives rather unclear!

I said "qualitive".

The explanation for 10 year olds: many particles, including the electrons in the atoms which make up you, the Earth and everything are called "fermions". Experiments have shown convincingly that two fermions can't be in the same place at the same time (a simplification I gloss over because I do not want to explain spin at this point) so they have to keep a minimum distance apart. Gravity tries to squash them together, this is counteracted by the fermions not wanting to be squidged too close together.

Some other particles, such as photons which are particles of light, are called bosons.  Bosons are different from fermions because they can all be squidged together in some situations. This is the main reason why a laser pointer has a very narrow beam, is a single colour, and looks speckly.  (Again I over simplify).

When the explanation is done face-to-face I draw diagrams and go into slightly more detail. I do, of course, answer the inevitable questions as best I can.

8 minutes ago, Bivanus said:

Interrogative answer: How many of us remember who Lee de Forest was without looking it up ? Having look it up , what was he in your eyes - a theoretician or a practician ?

At least one: me.

Both, IMAO. The two are not exclusive.

2 hours ago, andrew s said:

In that sense we don't know what anything actually is. What's a table or chair? What's water or air?

All we have are mental or mathematical models

 Regards Andrew 

Try asking a secondary school teacher why everything, the Earth included, doesn't fall to the centre of the Earth because of gravity.

Rather hard to explain without a qualitative knowledge of Fermi-Dirac statistics. With that knowledge, easily explicable to kids 10 years old or younger (again, I have practical experience), the answer is obvious.

9 minutes ago, saac said:

S3 school pupil - "what's an excitation", "what's a field" "what's and excitation of a field" "how do you know". "Can we do an experiment"  , " minutes later "what is a excitation". 

Ok it's like this, atoms comprise the proton and neutron in a central nucleus with protons orbiting around them just like the planets orbit the sun.  It's actually a little more complicated than this but this simple model will help us get to where we want to get.  School pupil - "why didn't you say that first".

 

There is a time for everything and a season for every activity  

Jim 

A damning criticism of the current education system.

I  have, taught the concepts of quantum field theory and general relativity to kids under 10 years old -- my great-nieces to give just two examples. To the best of my knowledge they understood the concepts. Of course, this was profoundly subversive and doubtless caused disquiet among school teachers who were not so well educated. So be it.

1 hour ago, saac said:

I'm not entirely sure Andrew but I suspect that it is rooted in course design and the sequencing of ideas or concepts.

Define the term "particle" as being an excitation in the relevant field and everything goes away.  Phonons, magnetons, electrons, quarks, gluons, Higgs bosons, etc are all equally particles in this picture.

IMAO, the real problem is with people thinking as particles as being very small billiard balls. Physics has come a very long way beyond that picture, starting about 100 years ago.

We no longer think about combustion as involving phlogiston exchange or chemistry in terms of 4 elements (air, earth, fire and water) so why don't we update our ideas about the nature of particles?

23 hours ago, Macavity said:

Well, maybe my attempt at "Polemic"(?) failed a bit... In the face of
Astronomical common sense?

Common sense ( compound noun ) a frequently used oxymoron.

c.f. military intelligence, civil servant, Microsoft Works.

On 08/08/2023 at 14:45, saac said:

It can be both or singular surely.  In education (secondary school) it is the practical element of science that places the cap on class size. A non practical subject such as Maths, English Languages etc can have a maximum of 30 pupils while a science class (single subject or composite) is capped at 20. 

To coin a phrase: that is a little local difficulty,

No ${DEITY}-given reason to set an upper limit of class sizes.

On 06/08/2023 at 23:15, Highburymark said:

Instead of DSOs, consider DSEs.

Do something else. 

Lots of other things to do, I find. Even in astronomy and during clouds, etc.

Analysing old images, keeping the web site updated, Zooniverse work, keeping up to date with the literature, ...

1 hour ago, peter shah said:

First light always is quite an anticipated moment but considering the collimation and focus issues (pretty much normal on new kit) its not a bad result at all........

Thanks.

This was not truly first light from the kit. It was the first time the scope had been used since March and so "in one sense". The process of mothballing the scope (such as protecting it from volcanic ash which is still blowing in the wind around here) and bringing it back into service inevitably moves components. Then fixing sundry mechanical, optical, electrical, and software problems before it can be used at all also degrades performance. It generally takes me a couple of sessions or so before I am satisfied with it again.

22 minutes ago, vlaiv said:

It will certainly end up in practical again - like atom is made up out of some particles - let's try to split it

 

Until Rutherford bounced alpha particles (the nature of which was not well known at the time, they could well have been charged atoms as far as he know) it was not at all clear that atoms were made of particles other than electrons. The size of atoms could be estimated at the time but it was generally thought that they were fairly uniform balls of mixed positive and negative charges.

Seeing alpha particles bouncing off at immense angles convinced everyone that an atom has a tiny positively charged nucleus (a particle) inside a negatively charged ball which was presumably made up of electrons. A fuller theoretical model of the atom came along later.

Finally managed to get some images last night after several months. Most were of variable stars and asteroids for subsequent measurement but a few subs were of the globular cluster NGC 6712 in Scutum. It lies in a very rich part of the Milky Way.

I have no idea why it is labelled "weird globular cluster" in Interstellarum and perhaps someone can enlighten me. The optics were not yet fully collimated and focused so this one doesn't look as good as I would hope, in particular there is some astigmatism, but as a first-light in one sense I am not too unhappy.

I was a purely visual observer until early 2018, when I put a cheap Canon DSLR (£50 off eBay) and a 200mm lens (another £20) on a tripod that had been kicking around for years and previously used for holding binoculars. Total outlay: much less than thousands.  It was easily good enough to take measurable star fields and so I got into precision photometry that way.

Later that year I bought Tacande Observatory. The main kit is purely imaging. Well, I can replace the imaging train with a filterwheel/eyepiece combination but choose not to because re-calibration after reverting to camera is too much hassle.

So these days I am now fully imaging and still measuring the brightness of variables, as well as astrometry of asteroids, tracking down minor bodies in the solar system and so on.  I even take very occasional pretty pictures(*) but monochrome only because I am too lazy to faff around with all that colour entails.

May get back into visual again because a rather poor quality Meade is on-site. Another delivery of round tuits will be needed before that happens.

Paul

(*) Last night NGC 6712. Does anyone know why it is marked as "Weird globular cluster" on Interstellarum?

Cloud stopped play after 4.5 hours of observing. During all that time not a single packet out of well over 50,000 was dropped between the CS and the FS2.

I am now convinced that the problem was overheating of the FS2 and the addition of the fan has fixed it. I accept that it may only be a temporary fix.

As noted above, it is possible to buy a ready-built unit for €220 from https://instein.eu and you may wish to go down that route.

If you wish to replace the FS2 with another, they can be shipped to UK, but not NL. I often travel between UK and ES ...

47 minutes ago, Carbon Brush said:

On a different note. ROHS rules and regulations.

Components sold within the EU have been ROHS compliant for many years. The law became active in (I think) 2006.

Thanks. I will run with the fan for a while to see whether it helps, though I realise that all things die eventually and need to be replaced. Not had a clear night since 31 July to check it out.

The RoHS issue is, I believe, nothing to do with the components used. As you say, all modern components are compliant. The issue is that the regulations required too much administrative work: setting up procedures for end-of-use return of items sold, paperwork to demonstrate compliance, and so on. The cost of that work outweighed the profit made on selling to the EU market.

Why use wireless?

Cat 5 ethernet cable will run up to a 100m with ease, in my experience, and it is much faster and more reliable that WiFi, again IME. Just be careful not to chop the cable when digging your garden! Even then, running it through a length of standard hosepipe will give a great deal of protection.

As noted earlier, a computer out at the telescope will need weather protection but a simple box, possibly cooled with a fan blowing out for summer use, will take of that. Power should not be a problem: extension cords are pretty cheap if you don't want to do a professional job with armoured cable.

My TCS necessarily runs Windoze (a sore point, so don't get me started) but once everything is set up I often connect with RDP from a Linux box back in the house. It just works for me, no hassle, no fancy configuration magic.

Also as noted, small computers, either Windoze or Linux, are pretty cheap these days, especially second hand. A 10 year old laptop is easily capable of driving a telescope and storing gigabytes of subs. If those subs are stored on a SMB or NFS drive you can do the stacking on any system you wish.

8 minutes ago, nitram100 said:

Finished a 12 hr shift, setup the scope and left it for an hour to cool down in the garden with perfect blue skies. You would think it would be safe with the forecast?

Two days running we had brilliant blue skies all daylight hours and then 100% cloud cover 30 minutes or so before sunset. No astronomy again tonight.

It can be just as frustrating in La Palma as in England. You are not alone, IOW.

Cloud stopped play.

The cloud was so low that tiny water droplets could be seen drifting around in front on the torch used to walk to and from the observatory.

Just kludged together an old 12V, 4W, 100mm diameter cooling fan and a grotesquely over-specified cable and strapped it to the FS2 with cable ties. Both components were found in my junk heap and the cable, which can safely pass 50 amps or more, just happened to have the right connectors  at one end to attach to the FS2's PSU.

There is a pretty ferocious draught blowing over one of the two large surfaces on the FS2 now. Let's see if it helps enough.

I would prefer not to spend several hundred EUR/GBP/USD if I don't need to.

15 minutes ago, fate187 said:

I am also using a FS2 on my Alt 5 ADN mount. And I am also interested to switch to One step box. I couldn't be bothered to built my own, so this ready to go box is appealing. If you have bought this unit and you have gathered experience I would look forward to your experience :).

A hand controller would be nice though.

The raw controller is given as €220 and a hand controller as an additional €110 so the latter is presumably available.

I am still waiting for a reply to my inquiries. Perhaps a phone call may be more effective.

BTW, although the FS2 is not available in the EU, I am in the UK half the years and the UK is not in the EU. If you need a replacement ...

Folk in the UK may be having issues but here in La Palma tonight the sky is cloudy and hazy at the same time. The moon is visible but not much else, at least in part because of the moon.

Still hot and very sunny during the day. I now have somewhat sunburnt arms from repainting the dome on Sunday where a few rust patches had been treated two days earlier. 32C air temperature, very nearly no wind, absolutely no shade and vertical sunlight is definitely unhealthier than cool rain.  Nothing like a bit of radiation damage ...

27 minutes ago, Space Hopper said:

But I really need to have a good think about where i want to go with the hobby. I'm not 100% sure to be truthful.

Go to a remote telescope facility, perhaps?

Some provide the telescopes, mounts, filters, camera, etc. Others allow you to host your own equipment,

I offer the latter to Kevin Hills who has a 50cm astrograph in a dome next to mine, All I provide is the land, the electrical power, internet connectivity and tech support when I am resident in La Palma. When I am not here a guy who used to work at El Roque De Los Muchachos does the needful.

In principle I could do the same for others but the infrastructure and management procedures are not yet in place.

8 hours ago, Mr Spock said:

Is the end in sight? As well as the cloud it's been horribly cold - averaging around 5° below normal the last few weeks.

Rather warmer here. A couple of days ago I treated various patches on the dome with rust remover and then painted it with high-TiO₂ paint today.

Air temperature in the shade, of which there was none next to the dome, was 32C. Standing in almost vertical sunshine next to a white dome (and becoming whiter) on a roof covered with an aluminized almost waterproof(*) membrane and the effective temperature was much higher. Not pleasant, IOW. The paint in the can kept drying out and had to be diluted with white spirit.

After finishing, and after removing as much paint from my hands as I could, and having put the work clothes in the washing machine, and after having a shower I headed off to my local. The car, having been out in the sun, claimed it was 38C.

So the temperatures here are warmer (I won't say better) but the skies are very far from perfect. Clouds are building up now and last night was very poor because of brilliantly moonlit haze. I estimate the limiting naked eye magnitude was 1.5 to 2.0.

(*) which will be replaced in two weeks time. More expense, but at least the charts and reference works won't get soggy again.

Now sure the FS2 is overheating.  The case became rather hot after around 3 hours use but at least I took some useful data on three variables before giving up at 23:15 UTC.

The sky was rather hazy and very moonlit, so I was quite pleased to get down to V=16 or so with adequate SNR. The air temperature was still 25C at close of play, which was close to 10pm local solar time as La Palma is about 75 minutes behind Greenwich.

Getting very close to buying a On Step box, which is made in Spain and should be quick and easy to ship. Already asked sundry questions about how much work will have to be done to convert cables, etc, to that system from the FS2.

No need for you to emigrate. If your kit emigrates to somewhere with good internet connectivity ...