iantaylor2uk

I recently got a ZWO 585MC cooled camera, to pair mainly with my Tak TSA 102 f/8 refractor. This gives a better field of view, smaller pixels, and higher quantum efficiency compared to my other camera (a ZWO 071MC Pro). One benefit of the smaller sensor is that I don't need to use a flattener. I managed around two and a half hours last night on M51 and got the result below (from stacking 149 60 second images in DSS and then some further processing using GraXpert, Affinity etc.). An IR/UV filter was used. Although the moon was up, the end result was fairly reasonable, to me. Autoguiding, autofocussing etc. was all managed by an ASIAIR Pro and I used my RST-135 mount.

That may be true, but anything other than hydrogen and helium is present in extremely small amounts as the composition of our sun (by mass) is estimated at 92.1% hydrogen and 7.9% helium.

The only way time is measured in relativity is by using photons - think of special relativity where Einstein uses mirrors and photons to explain the change of length with speed. If there aren't any photons, there is no way of measuring time, and so I doubt that special and general relativity apply in an era before photons.

As I understand it, inflation occurred very early after the big bang. According to Wikipedia, inflation occurred at times from 10-36 to about 10-32 seconds after the big bang. However, particles (neutrinos, electrons, quarks etc.) are not thought to have formed until 10-12 to 10-6 seconds (https://www.astronomy.com/science/how-did-the-first-element-form-after-the-big-bang/) and protons, neutrons, atoms, didn't form until a few minutes had past. I don't believe there were any photons around at the time of inflation, so the "speed of light" as such didn't exist when inflation occurred, so I don't really see what the problem is.

I once had a 12" f/4 Orion Optics reflector which I bought second hand from someone in Macclesfield back in 2009. This was an earlier model than the VX range. It was quite a beast, and I used a Losmandy G11 mount for it and even did some imaging with it. Even though OO scopes are lighter than most other makes it was still quite an effort getting it on and off the mount. Photo of set up below, although I no longer have the scope now. Had some good visual images of the moon and planets and some of the brighter DSOs.

Some interesting info about the new Condor telescope can be found in the link below: https://phys.org/news/2024-03-condor-telescope-reveals-world-astrophysicists.html

It would be extremely strange if the one way speed of light is not the same as the speed of light as usually measured.

I've had this camera for about 3 years or so and it's been excellent. Never noticed any amp glow and have got some great photos from it. Newer cameras, like the 533MC will have a higher quantum efficiency (the QE of the 071 camera is only about 50%). I tend to use mine at quite high gain (200, when unity gain is 90 and max gain is 240). These cameras can also frost up if you cool them too much or too quickly. I only usually cool the camera to 0 C.

Sorry I meant that there is a standalone version of GraXpert which can be used very simply for processing raw files

There is a standalone version of the tool for windows that can be run outside of Pixinsight or Siril which is very easy to use on raw fits or tiff files.

You could try using GraXpert, it should be able to take raw files from the Seestar and it's pretty easy to use.

Another issue is that it is well known that fractals appear almost everywhere in the natural world (see for example Mandelbrot's book). These usually arise due to scale invariance and simple rules. However, such curves are usually not differentiable, so standard methods of analysis (calculus) are not easily applied to them. If space-time is in fact fractal, then a lot of the maths being done may need to be revised. See for example: https://arxiv.org/abs/0811.1396 This was published in Physical Review Letters in 2009 (this is the best physics journal that exists)

I don't think you have answered the key question of whether particles are "in" space-time or some how "sit on top of" space-time. I've seen the explanation in terms of field before but this simply begs the question as to which is the more fundamental, space-time, or fields?

There are plenty of examples. The one that quicly comes to mind is: the whole of quantum mechanics effectively started because assuming that photons could have any continuous value of energy gave a result for the electromagnetic emissions from a blackbody which was plainly wrong. The only way the right result could be obtained was if photons could only have energies which came in discrete "chunks" whose value depended on the photon frequency. The assumption that a model is correct if it explains physical phenomena is, quite frankly, nonsense. Just look back in history, where Ptolemy's epicyclic model of the movement of planets, based on a sun centred solar system with lots of epicycles, gave excellent agreement with observations, but the model turned out to be completely wrong. When people do research, they ask "what if" questions. Einstein asked "what if the speed of light is constant" and worked out the consequences. It is perfectly reasonable, as a physicist, to ask the question "what if infinities do not exist in real physical processes" and work out the consequences from there. You are right that under such a scenario, space-time would be discrete so you would have to work out the consquences of this and whether there is experimental evidence of this being true. The problem I have with a continuous space-time is that it does not explain what particles are - are they "in" space-time or do they somehow "sit on top of" space-time. With a discrete space-time model, you have the possibility that particles could be discrete patterns of space-time, which could be hundreds or thousands times larger than the Planck length, but which to us would, experimentally, still be point particles. Think of Conway's Game of Life. This shows that a 2-D lattice, with simple rules, can give rise to stable structures, some of which can propagate. If we had 3-D discrete space-time, again with fairly simple rules, you could imagine that certain structures could occur in space-time, which we effectively see as "particles", and the quantities we call charge etc. could be related to the topological properties of these structures. If no-one asks such questions, no research would get done, and no progress would be made, so whether you disagree with what people are suggesting, it is quite right that people are working on different things.

I think the main part of the problem is that mathematical models are based on calculus, differential equations etc, which usually assume nice continuous functions and that can things can be divided infinitely finely, whereas we have leant over the last 100 years or so that physics is essentially digital and not continuous at the smallest scales.

I'm suggesting that if mathematical models of physical processes predict infinities then it is the model that is wrong, even if it may give a good description of the physics.

I believe this is exactly the same as the club which is being criticised! As I understand it, the person who started this thread was told they could attend 3 meetings as a non-member, and if they liked it they would need to join the club if they wanted to attend any more, which apparently involved filling an application form to be a member. Sounds perfectly normal to me.

I've been thinking a bit about these various videos, and the potential links to physics. I think a lot of problems arise when we think of infinity. I would suggest that infinity is a purely mathematical concept, and in fact never exists in real physical systems. There are a lot of particles in the universe, but I don't believe there are an infinite number. There are space time theories out there (loop quantum gravity for example) where there is a minimum size for space-time - crucially it can't get infinitesimally small. Some people may like string theory, but as I understand string theory just assumes space-time is there so is no help in understanding space-time. I know there are some cosmologists out there that think the universe is infinite - this is simply untestable, so you could argue it is not really a valid theory (since theories need to be testable, in my view). It would be interesting, I think, to further explore what the implications are if we decide, in principle, that infinities never exist in real physical systems.

Thanks for that vlaiv. I thought the one I posted though was pretty good at explaining things, although a bit long at 40 mins

Sorry - I only read the post quickly and didn't realize the top photo was with a different camera

I should have said the final result looked good to me, even though the subs looked over-exposed. f1.7 is very fast and even f2.5 is fast - I wouldn't worry about stopping it down a bit since you want to let less light through to stop it being over-exposed.

If it were me, I would up the f ratio to 2.5 or 3, and reduce the sub exposure time to 15 seconds. You could also try playing around with the ISO setting too.

sorry - i was trying to post the correct link using my phone and it somehow got the wrong one - it has now been corrected

Actually a much better video on the same topic is the one below (correct link this time!):

I think in physics there are lots of quantities (particularly in quantum mechanics) that potentially sum to infinity. However in any meaningful physical process it is the difference in quantities that matters so these infinities should "cancel" out. A lot of modern research is working out how to do this in a mathematical rigorous way.