Green Baron

Hi guys, expecting that there are some specialists here i allow myself to ask for help because it is of some urgency to me. I try to load these pages: sanitas.es/misanitas (no, i am not sick, but switching companies and need to cancel the old one, or i'll pay double ...), but all i get is a protocol error with no way to to load the page, to work around or to force the browser to just do it. It is a link i got from the letter of the insurance company. I tried Firefox version 3.6, 45.6 (Iceweasel), 49 and 50 under Debian 8.6, Ubuntu 16.10 and Windows 7), i tried Opera stable (Debian 8.6 and Windows 7), i even installed Chromium (current version and repository version under Debian 8.6 and Windows 7) and an old version of the Internet Explorer (the one from Windows 7 SP1) but nothing works. All i get is either an ERR_SSL_ERROR_NO_CYPHER_OVERLAP or the message that the server has reset the connection while loading the page. I messed in firefox with the about:config settings for tls and ssl as described in various forums on the internet or the firefox support pages, but nothing works. I have seen the page loading on the insurance agents computer, so this might be a problem in my network. Any ideas ? Cheers gb

Emancipate yourself from Wikipedia ! :-) It's easy, and i hope this is not too simple an explanation, if it is then i apologize: A star radiates a continuous spectrum. Parts of the spectrum are absorbed in its atmosphere, depending on the elements present. These parts correspond to dark lines in the spectrum, that's an absorption spectrum. It tells us about the elements present in a star's atmosphere, the star's atmosphere composition. On the other hand, if a gas is heated to a point where its elements start to radiate (excited electrons fall back into their original state and send out a corresponding photon), the corresponding peaks in the emission spectrum tell us about the composition of the gas. The Hertzsprung-Russell-Diagram and the categorization of stars is the compilation of our knowledge of the development stars. It maps the surface temperature (colour) of a star to its brightness (moreorless). There are different classification schemes. I am not sure, but i don't think that something as heavy as a B-type (Rigel) is a predecessor of a bright A-type (Sirius comes to mind ...), ... but this all is just a hobby of mine :-) Edit: because the visible matter in the universe is mainly hydrogen and helium + some impurities do not be surprised if you stumble upon testimonies like "there is hydrogen, helium and metallicity". For astronomers, everything heavier then helium is a metal, they are not as sophisticated as the chemists ...

Hehe, exactly, i started playing computer games when i was at university (the first time). Just because personal computers didn't exist when i was a child :-)

How big is it ? Can Cygnus be seen from the Atacama desert ? Do they have better things to do :-) ?

Assuming balls, an elastic collision, linear movement (no deformation, no energy conversion, conservation of momentum), then the ball with m/2 (50kg) would gain 4/3rds of the speed (13.333..m/s) and the ball with m (100kg) would carry on with 1/3rd = 3,33... m/s. Total speed difference stays 10m/s. http://hyperphysics.phy-astr.gsu.edu/hbase/colsta.html 2D elastic collsions involve angles. http://farside.ph.utexas.edu/teaching/301/lectures/node77.html If the collision is inelastic (deformation) or heat conversion gomes into play then the math gows over my head. The same with 3D-collisions, uncentered hit, spin ...

I doubt that 100 cubesats will make a good telescope, since the small surface areas won't collect enough photons for a meaningful application. Also, how would such a swarm be controlled ? You need a mirror, a camera, a little computer, a transmitter for the data, a maneuvering unit ... all in a 1l-box. or a quart or two pints if you like it that way :-) A single 1,2m-mirror would already be a better solution. But esa/nasa/other are already a few steps ahead. For example, it is planned to do really (like: ludicrously) large baseline interferometers in the 20s. Example https://www.lsst.org/lsst/ on earth and http://sci.esa.int/euclid/ in earth-sun-L2. Challenging but possible and planned.

But, we have already discussed it .... Cheers, gb Edit: ... dimming the hopes/beliefs in alien megastructures: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.261101 Again i feel urged to cite the first sentences in the prefaces of most physics/astronomy/cosmology books: Natural science is about explaining nature. Tools are physics and mathemagic. Aliens or creators are not natural science because they offer an unfair and illegitimate shortcut through the understanding of nature. That does not mean that aliens do not exist but until proven otherwise working without them has a higher chance for us to understand nature. Humbly supposes the gb with a red Christmas cap :-) Editedit: to summarize the outcome of the paper, because i found it hard to understand. The star could be in a state of selforganized criticality. Like a system that is on the edge between two states, e.g. magnetism switching or so. Thus parts of the star are temporarily in one state, other parts in another. The paper is based on statistical analysis, but there are more stars with a similar behaviour.

DSO and planetary are mutually exclusve if you don't have a very flexible equipment with correctors/reducers and telecompressors. I will post a photo of my setup for DSO later. My equipment is ready now but the weather, according to the season, bad. In the meantime, what you can do, is visit astrobin.com and have a look at what people are doing with amateur astrophotography and what equipment they use. Really, it is difficult to recommend a single telescope. If you do want a Newton then pls. search the web for Newton telescope setup and collimation. You'll need that knowledge in the dark and with sleepy eyes. On the one hand you get a lot of aperture for little money but in exchange you must adjust scope as well as balance which can be frustrating in the beginning. You mentioned a piece to bypass the eyepiece. Is that a field corrector ? Or just a camera adapter without any optical elements ? The latter is used to bring the camera chip into the primary focus of the scope, which is easy. The first is an optical element to correct the image away from the optical axis (off axis aberration, aka coma). Your sporty f/4 Newton will probably show heavy coma depending on the size of your camera chip. These correctors have a distance at which they deliver a corrected and sharp image, and that must be met very exactly (sub-millimeter). That usually leads to a stack of rings and adapters. There are many systems to connect a camera to a scope. For sub-fullframe one of the most used is T2, which is a special M42*0.75 thread. Other, larger ones are based on the 2" tubes (M48) which is ok for APS-C chips, the larger 2.5" or 3.5" focusers that are used for full frame camera chips (36*24mm)* are based on M63 or even much larger. You will have at least one adapter for your camera on the one side and the scope, or, in most cases, the corrector on the other side. That is the setup many (most ?) people use who have bought their struff one by one, telescope, mount, corector(s), camera, filters if applicable etc. @cxg2827 uses a setup with a Celestron C11 and Hyperstar, which is very special to the telescope brand he uses. The correctors are built in (Schmidt-Design or the Hyperstar-Corrector). It is very flexible and could be used for DSO and if you switch camera position and focal length for planetary imaging as well. But see what a C11 EdgeHD with Hyperstar and a huge mount (CGE-M ?) costs and weighs. Success would probably be faster with such a setup (though i personally like apochromatic refractors, but that's religion if you know what i mean :-)). I don't want to talk bad about a the Newton, it's just a sporty machine (especially a short and "fast" one like f/4) for someone who likes huge apertures and who is ready to dive deeper into the matter. Visit the hobby astronomers forums for more confusion info :-) * Newer generation chips are often quadratic (why not round i ask myself ?)

If you want pointy stars then you will need a tracking parallactic (german/equatorial) mount and a means to adjust it exactly parallel to earths axis. A polar finder is a must. That'll be good for 2-4min exposures in most cases. I strongly recommend to use an autoguider, either off-axis or through a small guiding scope if you're into deep sky objects (like nebulae, clusters, ...) because you easily run into 10min exposures and longer, even with a decent CCD-Cam. As @cxg2827 said a mount at its limit will make a photographers life miserable. I know what i'm speaking of, now i have two mounts, a cheap small one and a "real" one. For a ten inch mirror of 12kg + 5 kg equipment i'd recommend a mount that can carry at least 25kg. A Skywatcher EQ-6 on the cheap end, a Losmandy G11 for life or anything in between. If it's the Orion 10" f/3.9 Newton you're dreaming of (what makes it an astrograph, i don't see any correcting equipment ?) then be warned: collimating a f/4 Newton can be sporty and you'll probably do so multiple times over the night as temp changes. Also a Newton has the camera sticking out to the side which makes for a terrible balance. If the tube and focuser aren't extremely sturdy then you'll have a distorted picture field. Also you'll need a coma-corrector if your cameras chip is 4/3s or larger. btw., in most cases the scope (if it's not a sexy apochromatic refractor) is not the most expensive part in a photographic setup. It's the mount or the camera. Visit cloudynights.com and browse the forums for more info ;-)

Hello Veeltch, i had a look a few days ago, didn't take pictures. I don't find it that interesting and am more (trying to get) into deeps sky objects. It's around half-Venus, bright and white. For planet pictures i wait for Jupiter to return in spring (or so). I'm having weather problems here on La Palma island too. Since 3 weeks now i'm trying to adjust my photo equipment. Either the moon was out, it was cloudy/rainy or too windy. And now the neighbour has hung a terribly flashing christ-mess illumination over his terrace. His house is 100m away, yet it flashes in scintillating colours all night long. Energy is far too cheap ! The next days shall be windy/rainy they say. And i hope that the light show is over soon ... but then the silly moon returns. sigh ... Edit: Venus in greatest elongation on 12th of January, i read

He, that's Loderunner :-)

LoadLoderunner on the Apple ][. But I wasn't a child any more ... oh and Ultima. No damn 2,3,4, ....

If you want to dive deeper into it i'd suggest to start with nature geoscience for instance or the egu. Elsevier has geoscience journals as well. Search result here. These are all peer reviewed papers, dry reading but informative. Asteroid impact is, though, not a major research field of geoscience ;-) Cheers gb

Insofar as a higher or deeper part of the water column is disturbed. The tsunami earns its name on shore.

Sorry, if correct someone. A tsunami, like any wave in water, actually does not move water. Particles of the water make an orbital movement, they circle. After a wave is through everything is where it was before the wave. Particles circle up on the back, forward on the crest, down on the front and back on the bottom of the wave. The orbital movement takes place up to a depth of a multiple of the waveheight (5-7 ?). If there is no seafloor the wave moves freely without overturning. Compression and slowing of a wave in shallow and/or norrowing water is what causes a low but fast moving wave (such as one from a small/medium impact or a submarine landslide or volcanic eruption) on the open water to become a slow, towering and overturning wave on the shore. The lower part of the orbital movement is slowed by the ground, thus the upper part overtakes and overturns. An overturning wave on the beach moves just fast enough to take the illusion of an escape from a good sprinter ... The above award winning video is not exactly what geology teaches about impact tsunamis (this is only the first result on the search list) or what a stone thrown into a paddy does to the spectators ... so, yeah, nice movie, i don't believe it as long i don't know what assumptions they made for the wave buildup, propagation and modelling of the shorelines. Seems to me that major effects in wave propagation have not been taken into consideration. Again: a tsunami on the open water will barely be noticed, only very near the impact site or submarine landslide. Bad things happen only at the shores. Another example is the Krakatoa eruption in 18813. Ships on sea near the site of the explosion didn't notice much of the waves that each explosion caused though they were covered with ashes, on the shores the waves built up 30-45m, the final big bang up to 60m.

First semester sedimentary geology: never judge an outcrop from afar. Never. Judging from the satellite foto alone is like the little girl visiting Neuschwanstein castle in Bavaria and excitedly shouting with her high child voice: "Look ma ! It looks like disneyland !". A valid analogy, but the wrong conclusion. Fans like those on the picture can be build by gravity alone if they have enough time (see structures on Ceres) or by steady winds. On earth these structures build up much faster due to higher weathering rates, precipitation, frost-changes, chemical weathering etc., on Mars they have millions of years time to do so. I said that before: as long as no robot took a thin section of these structures under a polarizing microscope i will express my doubts about it. :-)

Groups and students only afaik. But a visitor center is under construction since this year. I wasn't up there for a while, if weather permits i'll make a visit later this week and come back with a few up-to-date fotos. It's a long and winding "road" ... :-)

Aerospace nope. But R&D. I can see the Roque de los Muchachos from my terrace. Not the telescopes though, they are on the other side of the caldera rim. :-)

Not my field either, but it sounds like yet another one feels uncomfortable with and tries to work around the dark matter. Cosmologists might have problems with that. Dark matter and energy are widely accepted concepts. I don't understand this: "However, the mass of the dark matter is a free parameter, which must be adjusted to the observation. Verlinde's theory provides a direct prediction, without free parameters." From my understanding the portion of dark matter is quite well determined and it's stable, or am i wrong ? "The question now is how the theory develops, and how it can be further tested. But the result of this first test definitely looks interesting." Also i understand that the test was not an observational one. Dark metter and energy on the other side explain observations very well and have passed many tests, or not ?

Yep, sooner or later, as new insights and tech become available, i'll be corrupted too :-)

>300millisievert just for the 3 months transfer to mars corresponds with an increased cancer risk of alomost 4/1000, according to popular data and assuming a linear relationship between radiation and cancer risk. Somewhere i have read that 3 sieverts lead to acute radiation sickness, lesseons learnt from the nuclear accidents ... ok, this is all pop science data, but it doesn't sound that inviting to me. I stay here. I love fresh vegetables :-)

Of course, not going beyond leo is something like the earth is in the center and jupiter spirals around. @magnemoe said that there should be data from deep space probes. I once searched, but even the NASA site admitted that the radiation thing in interplanetary space is mainly unknown. So do the very few clinical papers i found. It seems to me that it's not only ionizing radiation, it's also particles that can do real damage to the vessels in the body. Furthermore, besides the decay in bones and muscles, the blood vessels are damaged/stiffen by low g, thus influencing blood pressure and circulation in the body. I'm on thin ice here, my personal knowledge about medicine is limited and that's boasting. But the guys returning from space after a longer stay are in a bad shape. And they where really fit when they left ... blabla, i bore you. Well, we'll see. It seems like SpaceX played too fast forward with new materials and procedures and now need a little contemplative phase to get things running again and on a safe basis. Somehow i understand the guy if he thinks: "Ha, i'll show those bureaucrats what performance and progress is ! We're first on Mars !". Many of us would do something like this if we had the means and the money, wouldn't we :-)

Ah, i see. Yeah well, i would say that the picture about radiation will become clearer when the new generation spacecrafts go out to collect data. I don't know about the plans for the first flights of Orion etc. pp., i'm just following the officially released news, but i think that awareness grows with technological possibilities. I remember having read about a possible mission just beyond moon orbit, maybe you guys know more. Concerning low g and diet ... well too much speculation for my low level state of knowledge. So i'm probably on the side of your "pessimists", read non-knowers :-) If i had to bet on a date for a first mars mission i would put it on one of the windows in the late 30s or even 40s, assuming that development goes well, not too much pops on the launchpad any more and funds aren't cut. That doesn't belong in this thread, but i am very much looking forward to the new generation of instruments, toys for the astronomers and astrophysicists. Namely E-ELT (40m-Monster being built on Cerro Armacones), TMT (soon(tm) being built either on Hawaii or right here on La Palma), GMT (Giant Magellan Telescope), LSST and the first humongously large baseline interferometer with Euclid in earth-sun-L2 from 202x on ...

Yeah, there were two different things in the op: the sloppy handling of the effects of a nuclear bombing one the one hand and the statement that a manned outpost in the solar system is possible on the other. I'm totally with you @kunok, we need more research. That has nothing to do with conpsiracy or apocalypse, just missing data. Sending people out now means sending them to die. And not of old age.

That's all science fiction. It is not pessi- or optimistic, just science fiction. Maybe in 50 or 100 years part of it is reality, nobody knows. Edit: ninja'd Yes, I am aware :-) And i am aware of higher cancer rates and mortality even after 60 years. I am aware of restricted zones on the former test ranges and around the sites of nuclear accidents. I see that there is a tendency among some to deny this but this ignores reality and is not helpfull in assessing the risks. Saying that it takes only weeks is wrong. The above link is just one example, search by yourselves. If you take a look at the isotopes and their halflife you get a feeling of the time scales.