ollypenrice

I like dining out! More seriously, I'm not sure that Newton regarded space simply as geometry. I may be quite wrong but did he not conceive of it as having a fixed existence, rather as we conceive of grid lines on an OS map? Yes, these are expressions of geometry but they have an absolute relationship with church spires and crossroads, etc. Didn't Euler challenge Newton with a question like, 'What would happen if the Universe moved two feet to the left?' or something like that? It's a very long time since I read Westfall and I'm hardly on home turf with any of this stuff. Olly

I agree with Billhinge. The cube containing nothing is unconnected with the nothing it contains. Isn't this imaginary cube the same as the imaginary grid on which the Newtonian concept of space fatally relies? Or, to look at it another way, do two cubic metres of nothing contain more nothing that one cubic metre? Clearly not, so the cubic metre must be fallacious as a volume of nothing. Olly

Ypu're right, this conversation is doomed. Nothing will come of it. lly

Hmm... I was about to concede defeat and accept that the mass outside the nothing could be used to define its volume, but inspiration saved me at the last moment! Within the one cubic metre volume as you describe it, can we meaningfully describe a smaller volume such as one cubic centimetre? You might try to do so by defining it as a distance from the sides of the cubic metre - but that would be unsporting! lly

Excellent! I have a cubic metre of nothing and I find another cubic metre of nothing. Do I need two cubic metres of space in which to contain them? Or will they both fit into no cubic metres of nothing? lly

So that NOTHING! Brilliant, we got there. But... erm, what does it look like??? lly

OSC only. What I'm enjoying about the fast OSC system is that it pulls out more dust and less gas, in the time, than HaLRGB. Essentially I think that adding Ha can make you lazy when it comes to going very deep in broadband. Olly

Science being a culture of doubt, I'll embrace doubt. I must say that this object has the potential to be an artifact, to my eye, because it follows the outline of M31. This means it might, at least in principle, have been generated by internal reflection. On the other hand, if it is associated with M31 and doesn't lie much closer, it would probably have good reason to follow M31's shape. A control experiment might be to carry out the same capture and processing on another large, bright galaxy and see if the phenomenon repeated itself. Olly

Of course, the fact that time and space may both be illusory complicates things still further. Things do, indeed, appear to be separated in the dimensions of time and space - most of the time. In some circumstances, though, they don't. The entangled photons experiment provides one example. We are happy with the idea that time slows to a standstill at the speed of light. At a standstill, I don't see how it can separate events. What if space, too, can reduce to zero? If it can, then where would we put our hypothetical vacuum? 🤪lly

A very strong image indeed. Olly

My understanding is that, in such a vacuum, new particles would spontaneously appear. There is a minimum energy density which is non-zero. That's why I think it is likely to be one of those infinities which have no physical existence. Olly

I think all this tells us is that, without the tilt adjusters, your chip would have been orthogonal anyway. Somebody, somewhere, chose to use the tilt adjustment to introduce tilt. That's fine, but chips are not always orthogonal and Stuart's video tells us what to do when they aren't. It seems to me that your version is only simpler because you didn't have a problem in the first place - till someone put one there! lly

If you mean that 'nothing' cannot be measured, then I'd agree. I'm starting to see 'nothing' as one of those infinities of which physicists are suspicious. Olly

Mathematical physics aside, there is something odd about the idea somebody (by definition part of something) looking nothing. Where would be the boundary between something and nothing? How would it be identified and defined? I'm beginning to think that 'nothing' is a kind of infinity which exists only as an abstraction in our heads.. Olly

The tidal streams seen here are faint. Trust me! I have previously laid siege to them with the TEC140/CCD rig. This second attempt comes from just 4 hours with RASA 8/ASI2600 MC Pro/Avalon linear, expertly driven by Paul Kummer, the data pre-processd by him as well. What you see is a close crop from a focal length of just 400mm. There are very nice tiny galaxies as well. Distance to this interacting pair is nearly 80 million LY. Olly

If you were to use the Ha within the final luminance, would there not be a danger of it greatly suppressing the rest of the signal? Olly

^^ Sorry, nothing I can do will let me edit this post, which was simply to ask Vlaiv if he wanted my bank details for his transfer or my address for his cheque. lly

We don't. We like wiiiiiiiide open! lly

I was thinking along these lines. We are limited, though, to one shot colour, at the moment. The problem with going after the ultra-ultra faint stuff with a mosaic is that the calibration of one panel to the next is likely to damage the data at this very low level of signal. That's why the Samyang would be a good bet. Olly

The big improvement here is that you did not black clip the image. That's to say that you you did not bring the black point in too far. The sky is lighter and the faint arms have been preserved, not clipped out. Olly

No, I'm not having this. To quote Wittgenstein (and give my point a bit of gravitas ) language is public and if I asked you, or anyone else looking at my car, what colour it was you would say black. You would not say, 'It has no colour, it manifests the absence of colour.' Come on now, admit it! Olly

Since the mount won't allow the system to resolve at anywhere near its sampling rate, it may be that losses to the seeing fall within losses to the tracking error and so won't make much difference. Hard to know. I entirely agree with you on the use of a camera lens. Surely that's the way forward with a small chip, tiny pixels and no accurate guiding. When I started, I remember being very skeptical when people said, 'That system won't work.' I learned fairly soon that they were right, though. Olly

My thoughts... Whether or we call black a colour depends on the context of the conversation. In certain technical contexts it is helpful to call it a shade but in most cases it is more helpful to call it a colour. My car is black. It doesn't matter what we call it, we know what it looks like. In a line of ten cars of different colours, if I tell you mine is the black one, you will know which it is. You say, 'But also the universe is expanding into nothing.' This is not at all what the Big Bang theory says. It is not expanding into nothing: all that there is is expanding. If it were expanding into something we chose to call 'nothing,' that something would be part of the universe and therefore inside it. In order to 'look like something' an object must send light in our direction, either by emitting it or by reflecting it. If it does either, it is not nothing! 'Nothing' does not exist in nature. Even a perfect vacuum contains a minimum energy level which will cause particles to appear and annihilate at any time. (There's a good book on nothing by John Barrow. The Book of Nothing. It's worth reading.) If we look in a direction from which not enough light comes to stimulate the retina, we see black. Conclusion: when we look in the direction of nature's closest approximation to nothing we will see black, so 'nothing' looks black. However, that does not mean 'nothing' is black. It isn't black because it doesn't exist - by definition. Olly

The nebulosity has a 'billowing' look which is very appealing. Olly