andrew s

No good reason at all. The outer layers of super giants are decoupled from the core by a thermal lag and largely do their own thing. Obviously as the net energy output from the core changes it has a major influence on the outer layers over time. However, once fusion in the core stops and it collapses it does so far too quickly for the outer layers to react until they are hit by the neutrino burst and shock waves. Regards Andrew

I think different things are being confused here. Putting it in simple terms. For the mount to balance the moments tending to turn it one way must balance those turning it the other way. The moment is the mass x distance of mass from the fulcrum. So twice the weight half the distance for the same moment. Static force on the mount is proportional to the total mass twice the mass twice the force. Dynamic load depends on the moment of inertia which is the mass x distance^2 so as in the second paragraph in the quote the load on the motors accelerating the mount are reduced by increasing the mass of the counterweights. Regards Andrew

If you Google rotation of betelgeuse you will get lost of links to explain it's rotation. Its normally measured via spectroscopy but betelguse is so large it can be imaged via interferometry. Regards Andrew

Only intended as a little fun for a Friday afternoon! Regards Andrew

Not really you can coat almost any glass without its type have any effect. 😝🤪 Regards Andrew

All these fancy glass types is to get round the inherent flaws in refractors 😊 Regards Andrew

Static load is rarely an issue as bearings etc are very strong. It is the dynamic load that challenges mounts and here lowering the moment of inertia is good. Regards Andrew

However, two weights reduce the moment of inertia making guiding easier on the motor. Regards Andrew

@vlaiv here is a more accurate diagram for a non rotating black hole in Kerr metric coordinates. The radius of the event (Schwarzchild) horizon is r = 2GM/c^2 or about 3 km for a 1 solar mass object. See here www.astro.ucla.edu/~wright/bh-st.html for the explanation.

Certainly as long as you can pour it remotely. Regards Andrew

It is diagrammatic. The small light cones are drawn as for a flat space time and should be valid only at an infinitesimal point. A better diagram would have the cones narrowing and eventually being time like so the light lines don't tip back in time as you point out. Regards Andrew

This image shows how the light cones of objects are effected as a black hole forms. Far enough away nothing happens and the world line continue as before, but as you get closer you see the light cones tip towards the singularity. At the event horizon the light ray touch the world line of the event horizon. Further in toward the singularity all world lines tilt more and more and terminate on the singulariry. Strictly speaking the singularity is not a point in space time. Regards Andrew

The sun is not massive enough to form a black hole. It is the energy density that matters In the star it is too low by when it contracts enough the density gets high enough for an event horizon to form. Far enough away the "pull" is the same before and after (assuming no mass energy is lost). Regards Andrew

..but that is what I so like about astronomy as a hobby. There are so many ways you can enjoy it. From grinding mirrors to 3D printed spectrographs, pop to hard science, casual glancing at the stars to extracting the faintest wisp via image processing and freezing ones *** off to arm chair warmth. Regards Andrew

Possibly, but each to his own. I have a nice Hi Fi but the children just want ear buds. Regards Andrew

Time moves on. From sets of encyclopedias to the internet. From naked eye observation to space telescopes. From Daguerreotype to CMOS. Each generation approaches the world differently. As long as our curiosity is peaked does it matter? Regards Andrew

Has it got to Spain yet? Regards Andrew

Yes I used tapes on a Commondore Pet. But, just 14p per gigabyte memory today is just remarkable. I also used a hybrid analogue/digital computer the digital part of which had a ferrite core memory. The only time it gave problems was after preventative maintenance! Regards Andrew

Smaller than my thumb nail a SanDisk microSDXC card with 400GB of space. For a man who remembers floppy disks it's remarkable. Regards Andrew

Truly amazing, but I still think it looks like bubbling porridge. It is convection after all. That heat stop could power a small town, I wonder if they use the energy to generate power? Regards Andrew

It also governed by energy loss. With lots of viscous friction in gas rich areas the momentum perpendicular to the dominant axis of rotation gets dissipated heating the disk and flattening it. Regards Andrew

At best they are an aid to thinking at worst a block. I am very suspicious of the 'billions of xxx' arguments. Technically you can't define a probability density on an infinite dimensional set. In addition extrapolation from one case to 'billions' again seems unjustified given the circularity at the heart of frequentist probability theory. Even if one of the infinite typing AI robots did reproduce this post how could you know? Better to wait for observations. The history of Astronomy has shown that what we thought we new is often totally wrong when new observations are available. E.g. were not all planetary system thought to be like ours? Regards Andrew

While what @ollypenrice says is true for the telescope, don't forget a heated Obs will loose heat from its structure and this will cause convection currents which will degrade the local seeing. Regards Andrew

I thought you wanted a cullender to drain the spaghetti, oh well better luck next time. Regards Andrew

It does look as if the image is jogged every now and again. It could be seeing or mechanical but most likely mechanical given the length of the exposure. Regards Andrew