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Nik271

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Everything posted by Nik271

  1. Just a small correction: Fourier developed the theory of what is now known as the Fourier series for a practical reason: in order to solve the problem of heat diffusion, which leads to the famous heat equation, a differential equation in many variables. As far as I know Fourier was unaware of applications of his series to other areas of physics, in fact it took a long time for the theory of the Fourier transform to be developed rigorously.
  2. I finally managed to observe the area near Manzinus this morning, it was well positioned and easily visible even in daylight. I used my 70 ED with 6 mm EP giving x70 magnification framing the Moon well. The loss of contrast from the bright morning sky was not allowing higher powers. This is the approximate location of the lander marked on the simulated view from 8am this morning. The terminator is advancing rapidly towards it and I expect in a day or two the module and rover will lose solar power and shut down in preparation for two weeks of lunar night. It is unclear if they will survive it. In any case they will have accomplished the planned mission duration fo two weeks.
  3. Well done! As a fellow owner of a Skymax 127 I think you made a great choice. It's a great planetary and double stars scope. Epsilon Lyrae is actully perfectly within its abilities, the key is to know what to look for. Use about x100-150 magnification for a split, the two pairs are just over 2'' apart and will look very close together two discs almost touching each other. You need good seeing and ideally to be seated to avoid even tiny shaking of your head. A much easier and good looking double is Gamma Delphini, the nose of the dolphin, easy to find and you can split it even at x50 magnification. The ring nebula (and other DSOs) in the Skymax are best seen with some dark adaptation. Try to put a towel over your head to block the light, relax your eyes and look at it without staring directly (with averted vision). The ring shape gradully appears after a minute or two. As for the Moon, yes it is very bright at full moon, and actually not so interesting as the detail is washed out. At other times when the terminator is visible the view is definitely worth it! You can go to x200 and even above depending on seing, the view gets dimmer with magnification. Jupiter is a tough one to see fine detail because the contrast in the bands is low. The Great Red Spot is not very red recenly and not that easy to see. Around x150 (and often only x100 if seeing is poor) in the Skymax is generally the most I use for Jupiter. Saturn is easier, you should be able to see hints of the Cassini division even now at the extreme 'ears' of the rings, but againthis depends on the seeing being good. After the full Moon passes I recommend you try to see M27 the Dumbbell nebula. It appears like a delicate puff of smoke in the Skymax. Don't use very high magnification, about x50-70 will show it nicely. Enjoy your scope! Nik
  4. Last night I observed Iapetus with my 70mm and 100mm refractors. With the 70mm at x105 I could just about make Iapetus with averted vision. Saturn was only 12 degrees above the horizon and there was a lot of moisture in the air. With the 100mm at x175 Iapetus was a lot easier to spot even with direct vision. There was a dim star of slightly brighter magnitide south of it, Stellarium lists it at mag 10.5, so I estimate Iapetus at magnitude 10.6 last night.
  5. I was not aware that past observations estimated Japetus at magnitude 9 and even brighter. To me at brightest it seemed to be mag 10 when at western elongation. Magnitude 11.15 seems too low for the moment, given @IB20 's observation. Just shows making an accurate prediction is tricky indeed.
  6. Nice one! It has a very natural look, the colour is exactly how I see it visually. This must be from 6am today , I was observing Jupiter at that time and Europa was in a similar position. The seeing was quite good in Oxford, with the 127 SW mak I could see the banding very well, only the detail in the white zones was not as clear visually.
  7. I thought I will try to observe the landing site of the Chandrayaan-3 module. The coordianates are listed on the ISRO web page https://www.isro.gov.in/Chandrayaan3_Details.html I made a map with the location, it is not exactly on the South pole, but about 20 degrees north of it, near Manzinus U crater. Today the moon is very low in the sky for proper observation, but definitely going to have a look at this area next week.
  8. The motors on the EQ5 work at 5V just as well. I use a small lithium battery bank for charging mobile phones, something like this: It lasts for ages.
  9. The extra 'moons' are field stars. Apart from the Galilean moons the rest are near impossible with small telescopes. The next brightest, Amalthea was only discovered in 1882 with the 32 inch Lick refractor. The star close to Jupiter and opposite Io is magnitude 13, quite impressive if you saw that one. Or it could be the 10-th magnitude star further to the right, Jupiter was passing closer to it around midnight.
  10. On a positive note for visual astronomy, remember that unlike other type of pollution light pollution clears up quickly, it disappears the instant when the lights are off. It is by no means certain that in the future people will insist on keeping the lights on when not needed.
  11. Took a quick snap with my phone. It seems to be over now, amazing how quickly it changed.
  12. Big prom evolving now, seems to change shape very quickly, every 5 minutes or so
  13. Just had a look through some gaps in the rainclouds. Wow, so many big prominences today! Quite a few filaments too.
  14. What is the seeing on average in your location? The 150mm scope will give you quite a bit more resolution, down to 1 arcsecond, but it is no use if the seeing does not support it. The frac in the 100mm apertue is the most versatile. I have a 100mm ED doublet with FLP-51 glass, i.e. the cheapest doublet availble. I can easily go to x180 magnification and there is very little purple colour and only on extrmely bright objects (Venus, Sirius), interesting I don't see it on the Moon. I think a 100mm FPL 53 at F7 will show no discernible false colour at all visually at anything. I also have 127mm SW Mak (which is 120mm actual aperture) and also 180mm SW Mak. Cooldown time is not really an issue on the 127mm, but it is on the 180mm. For planetary my 127Mak beats my 100mm refractor in good seeing, despite the central obstruction. For planetary and visual this is my go-to scope. I recently split Mu Cygni with it, which pleasantly surpised me. My average seeing does not usually support the extra resolution of the 180 Mak, mind you it is still better in almost any condition, but not by much. So I would guess that the 150mm Mak will blow away a 4 inch refractor if the seeing supports it and from what I've heard of the 150mm Cassegrain that one may do even better. The refractor will be lighter and more portable though,and of course no annoying dewing (in the Mak) or diffraction spikes (in the Cas). So....not an easy choice. Bottom line from me: if you have good seeing go for the 150mm scopes, otherwise get a nice FLP53 100mm doublet. Nik
  15. It will be brightest near perihelion in mid September, unfortunatley it will be very close to the Sun at that time. In early September 1 hour before sunrise seems to be the best time to observe it with naked eyes. Fingers crossed!
  16. It's a question of priorities. Apollo took the lions share of NASA total budget in the 70s which was running close to 4% of the US federal budget in some years. Currently NASA's budget is 0.5% of the US budget, and I bet Artemis is just a small part of it. You can tell everything is going to be done on the cheap.
  17. Well done, John! Your 130mm refractor seems a very impressive instrument. After many attempts last year I managed to spot the companion of Dubhe with a 180mm Skymax Pro Mak at x450 magnification. Dubhe was near the zenith at the time. Even with 180mm aperture it was tough, the secondary is on the first diffraction ring and is three magnitudes fainter. The seeing was excellent last night, I just had fun with my Skymax 127, nothing very serious just some classic doubles and a quick look at the ring M57. Now I wish I had the big Mak out and tried something harder. Tonight also looks promising, the humidity is bad for deep sky but doubles tend to look good on muggy nights.
  18. Seems hard to find. It's mentioned in this memorial article about Struve in the Astronomical register from 1865 https://articles.adsabs.harvard.edu/full/1865AReg....3...89. specifically on page 94: Sadly I can't find any reference to a publication. The Bodlean library in Oxford does not have a publication by Struve from 1820, just checked their catalogue. Perhaps you can try asking someone at the library of the former university of Dorpat , now Universtiy of Tartu in Estonia. Surely they must have a lot of Struve's writings. Good luck!
  19. I believe Struve published his first catalogue in 1820 with just 720 double stars, it's probably what he refers to in the last column.
  20. If it's any help I recently carried Celestron 15x70 bins in my hand luggage on Wizzair from Luton. No problem at all.
  21. All things being equal the weight increases proportionaly to the cube of the linear increase, so 20% extra in aperture gives (1.2)^3=1.728 so about 73% heavier.
  22. I guess the meaning of consistent here is 'regular and not random'. Admittedly not clear how to define something which is 'not random' in a deterministic universe. Perhaps not random' should be taken to mean predictable by some rule that we can study, e.g a set of input data and an algorithm deciding when the event occurs. Anyway this is just my best guess.
  23. Indeed at the time 1930s there was a lot of research into measures motivated both internally within maths and by the need of applications to physics. Dirac's function is an example of a point measure and such measures (=probability distributions) arose from the need of quantum mechanics where the usual notion of eigenvalues of matrices is no longer sufficient. Instead one gets a probability distribution on the real line which is the 'spectrum' of a linear operator. In this way maths and theoretical physics developed together. I always thought that the main mathematical ideas were created first, in the 1900 by Hilbert, Lebesque and others but I may be wrong. It's probably hard to tell now who was influenced by who.
  24. Actually I was trying to say that there is not even one maths, what we have is a consensus maths based on a list of axioms that common sense tells us reflect the real world. But a different universe may require different maths i.e. very different axioms. For example one can describe the real numbers as a purely mathematical object with some axioms. A universe without real numbers will be something totally unimaginable to us, but still there will be some list of true statements about it some of which can be deduced from others by logical deduction. I would call this list the maths of that universe. So to return to our universe, we do have the current maths which we believe reflects the universe really well. But how well is really well? As we get closer to understanding some singularity point, say a black hole or the origin of the univese itself our maths may turn out to be insufficient. We can fix it by adding some more axioms according to what we discover further about the universe. So even the axioms of maths can evolve! I admit this has not happened yet in the real world, at least I don't know an instance where real applications have required rewrting of mathematical axioms. But it could happen. This is actually the same issue as the philosophical question, is maths created by us or imposed on us by the universe.
  25. When we propose to disregard some mathematical statements the truth of which we agree not to investigate then we face the question which are the mathematical statements which actually have 'interpretation' or meaning in the real universe? It gets a bit philosophical from here on. Ags points out the transcendental numbers, they are of a lot of interest to mathematicians but somewhat hard to find use in the 'real world' For example it has long been known (= proved) that e and pi are both irrational and even transcendental. It's still an open question if e+ pi is irrational. I'm sure a big prize awaits those who find the answer to this question. But is this of any use in the real world? Hard to see now, but who knows I think we can agree that the arithmetic of natural numbers is important, for example positive integers govern the energy levels of electrons in shell in the Bohr model of the atom and thus are key to understanding chemisty. The pereidic table is a consequence of some simple relations concerning integers. Some irrational numbers appear often in nature for example in the golden ratio, pi and e. I think we can agree these are also important. Suppose we have some very complicated logical statement about real numbers that we can neither prove nor disprove. Does this tell us something about universe? Godel and some later work by more people tells us the following: there is some polynomial P(x,y,z,..) with integer coefficents in several variables ( I think 13 variables is enough) such that we are not able to prove or disprove if the equation P=0 has integer soluton x,y,z,... or not. So is there some physical interpretation of this polynomial and its zeroes? I have no idea.
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