Green Baron

An amateur chip already has pretty a decent quantum efficiency (that's what your looking for i think :-)). In principle a single photon triggers a current, but the chip itself as well as the amplifier/electronics behind produce noise. The art is to part the noise from the signal. The overwhelmingly (ridiculously and subsequent ludicrously) large telescope will not be built because it makes no sense right now (and money matters too). We are technologically not able to actually use its potential. When the E-ELT was planned it wasn't even sure whether the aperture could be transformed into resolution, but advances in active and adaptive optics where expected. And so it came, it is now expected that the diffraction limit can actually be achieved. I can tell you that with a simple 12cm aperture amateur telescope (apo refractor) without any gizmos one is limited rather by the atmospheric conditions than the equipment. The atmosphere of an extraterrestrial planet cannot be observed directly with current generation telescopes. What can be measured is the light that passes through such an atmosphere (if it was present) when the planet passes in front of the star. Few actually do us the favour, but it has been tried with some. How many photons you collect depends on the aperture, exposure time and brightness of the object. The big fat GTC needs less for a decent signal/noise ratio than my poor little tube with a glass bottle bottom .... Inverse square of distance applies. But a supernova in M31 will so bright that youll see it with the eye. I guess you can see M31 itself (in summer again), here this is no problem. The detector is perpendicular to the path of the rays, even a slight tilt would get you a nasty distortion in the picture. No and yes. It's not the number of photons, it is the signal to noise ratio that is the interesting thing to practical astronomy. Astronomers themselves don't care about th earthly subtleties, they submit an application, if it is accepted a technician programs the telescope, the telescope does its work and if it screeches another technician leaves a few drops of oil in the cogs :-) btw. you can visit the websites of the telescopes around the world, i have seen online application forms or at leasts calls for applications for a season or period for the instrument. The GTC, ALMA, the VLT might be nice places to start ... Edit: i totally forgot to tell about focal ratio. This is of course and by far the most important indicator for the light gathering capabilities of any optical device ! E-ELT primary mirror will have 0.9 (but other foci like cassegrain, nasmyth may be possible) ! Which is one mind boggling photon collector. The GTC is actually not that sporty. My stuff has 7 or 5.8 depending on mods :-) Others here lie between 4 and 10. Old world amateur telescopes usually where around 10 - 30.

IR is a much wider spectrum than visual. What the chips read depends mainly on filtering. In the far infrared exposure times could get longer, but far infrared is not very interesting on earth. http://starizona.com/acb/ccd/advtheorycolor.aspx That whole radiation thing with the suit is somewhat dubious. Fact is, a human body radiates and not little. That energy must get away, our skin takes care of that to keep the temperature in a convenient area. Depending on activity, humidity and temperature, the skin can starts to evaporate water to cool the inside but the vapour needs to escape and take the energy away. Humans can't survive long in a 45°C humid environment, they'll overheat, proteins start to decay and the body functions come to a halt. If, like implied by the photos, no radiation escapes the suit then the inhabitant will soon die as the body temperature exceeds 40°C and humidity from sweat and insulation from the suit prevent getting rid of the energy. So i believe that they used a filter to narrow the sensitivity of the camera to a wavelength where the suit indeed might be impermeable while steaming more heftily on other wavelengths. Or they retouched the pictures. Or the victim model put it on, they took the photo and then it threw away the clothes. Make a test with a full neoprene suit with a hood in room temperature. You'll be surprised how warm it gets inside :-)

The school i once attended is asking for a donation. Complaining about this would lead to politics so i better let it be :-)

I never thought about how to get rid of the shell. It seems to be a complex process. I can't see any gas release in the video, though they say a pneumatic system pushes the fairings open. Maybe that means that pressure (out of something the blue cylinders ?) drives a series of bolts but nothing is released ? http://www.spacex.com/news/2013/05/27/spacex-fairing-separation-test http://www.spacex.com/news/2013/04/12/fairing Pressure in the Proton fairings is equalized as the rocket climbs, so it is not the overpressure that pushes the eggshells apart. Proton seems to use some directed pyro to release the locks and "pushers" to open them. Acceleration then leaves them behind, i think (?). http://www.ilslaunch.com/node/3307 Apparently Orion uses a similar thing, explosive bolts and springs to get rid of the overweight: https://www.nasa.gov/press/2013/november/nasas-orion-sees-flawless-fairing-separation-in-second-test/ But that was just a quick search ...

aehm ... the ITS doesn't exist yet ... as far as i read it is unclear whether there is a full sized raptor ... no dry mass, no isp (*), no dV. And one will have to wait for a somewhat convenient phase angle if one day someone should wish to return home again ... Just saying :-) Edit (*) except raw figures from a presentation

It is incredible and somewhat annoying how frequent and bright satellite trails became over the last years. Sky is rather dark here, slow moving faint objects or fast moving flares from rotating satellites (aka "iridium-flares") or short faint and bright flashes can be seen. Especially when the sun is low under the horizon, but also in the hours around midnight, high in the sky. You only need a dark sky to realize. ... if you see a shooting star, before wishing for something, make sure it's a natural one ;-))

300 years ago might have been rough times in the area, but houses in european cities followed tax rules as well, they were only allowed so much area and storeys and things (local differences !) ....

It varies and since the end of the medieval >500 years have past (depending on the measurement), with huge changes. Climate deterioration in 1600-1750, the plagues, wars over hundred years all were suboptimal. Industrialization was nice only for a very few. Late medieval was a nice time for a decent living to many, i wouldn't want to mess with one of the last knights. Much of the fuzz began after 1500. It is not as homogeneous. Speaking about western europe for example, in early medieval people in france, switzerland, germany, ... were as tall as today. Nice and warm climate back then :-) But it can vary within single generations and small geographic areas.

It might have worked ! And if only like "oh, that spec is the event horizon ? Interesting ...." https://blackholecam.org/astronomers-may-finally-have-the-first-picture-of-a-black-hole/ Heftily spreading rumours ;-)

Looks good. Stacking will indeed make things much better. Maybe the right distance camera/reducer can make the stars a little more pointy. But i was of the opinion that fewer long exposures are better than many short ones. The amount of photons from nebulosities is higher over a longer exposure time, there might even none from faint regions in a short time. So there is more information in a longer exposure. Stacking is to get rid of the noise. Noise is a randomly distributed while structures are there in every frame at the same spot, once aligned, and the stacking algorithm accounts for that. You can also try the L channel with varying exposure time, like 10*30sec and 10*4min per frame. I tried it with PicInsight and in principle it works, my core of M42 is hopelessly over exposed with 2min but i had two exposures with 30sec and they saved it.

Well, for those who like it in "combat scenarios" .... Good question, where does the heat go if it can't radiate ? And what about sweat ? I hope the battle is over before it gets too warm inside .... I'd rather continue to stay out of trouble :-)

lol That looks like a Tintin comic from Hergé out of another time Now, size doesn't matter (that much) among humans, cultural implications have a much bigger part. Even if it does not look like on the photo it may well be that the small guy has just attached the two big ones and is leading them away. Wasn't that funny ?

That is so cool ! An example for that island population thing is the woolly mammoth, mammuthus primigenius that grew as large as the asian elephant. It became extinct on the mainland at the end of the ice age, together with the large herds of cold steppe animals. But a few survived on siberian islands until ~4000 ago(*), they managed to "downsize" in very small indiviuals that could maintain a large enough population to keep sufficient variety in the gene pool. Where is my cute little mammoth ? :-)) Another and more lurid example are the huge dinosaurs that had enough space and time to evolve on a supercontinent. They grew smaller with the breakup of the continents and narrowing of the niches over a long time. The last ones (well, if you call 2-3m "dino" ...) made it to early paleogene, long after the chicxulub impact. (*) haven't had a deeper look into since almost 10 years. Maybe there is new data ....

The linked Homo floresiensis wikipedia article is a very bad example. We know little about that side line, but it is not a small homo sapiens, it was a species of its own ! What anthropologists have thought since the first reports: http://www.sciencemag.org/news/2016/03/hobbit-was-separate-species-human-new-dating-reveals

They live in boxes :-)

Growth hormones make people fat, not taller. On a short term variations in body height in local populations are caused by nutrition especially in the growth phase (too late for me :-)). This can clearly be derived from historical data (Edit: @adsii1970 got an example). Isotopes from bones give hints to state of nutrition, their size indices are a hint to body height. Over longer term and across different populations there is of course a genetic base as well. Like long tall Massai and short stout Inuit (i know, a generalization, but a tendency as well). Climate is also suspected to have an influence. Clearly nutrition, and a little lifestyle. Our parents had to work (most of them) ;-) Partly. Household animal's reproduction completely underlies human control. They are fed by humans and the ones for reproduction are selected by humans. Finding a generalization here is difficult ... Yes. The metabolism adapts quite quickly, not only as a species (because of the large number and genetic variety) but also as an individual, modification of the body due to lifestyle, nutrition, training, ... Underfed people are smaller (in general) than big fat westerners and an athlete is stronger than i am :-) I am sure there is PLENTY of research in the journals. Historical and archaeological data is also available in quantity. Edit: size of wild living species is not only determined by nutrition (short term, lifespan), but also genetic. Size of population to bearing capacity of environment, a large organism confined to a small area will either become extinct or grow smaller because the smaller ones have an advantage over the larger individuals, they often don't find enough to eat to support a big body. Directional selection in island populations.

How resonance herds the planets around trappist-1, and that migration from a disc inwards might have led to the stable state the planets are in and might continue to stay so: http://iopscience.iop.org/article/10.3847/2041-8213/aa70ea

Yeah, i understand the why they made Vulkan the way it is. Partly i think it is because of the mobile devices that lack the power of a pc. You can must choose exactly the functionality you need for your task, and nothing in excess. But on a pc that's a little annoying. I feel a bit like in the 2000s when they asked you those silly idiotic questions about the contents of your luggage and the background of your grand parents at the airport :-) Yes, i want to draw something, in that window, with the resolution specified, in colour. In this tutorial 1100 lines of code. No event handling, just draw. How much would that be in OpenGL ? 100 ? Including event handling like resize and escape to close ? It is just, really inspiring things where done with OpenGL when the shader pipeline was invented. I think of Outerra and Proland. So, i hoped for a step forward in terms of usability to a broader mass of aspiring wanna-be programmers. I am not afraid of malloc and free (though their time is over as well), with memory management i mean taking care that all your objects clean up nicely behind them. Which in the case of Vulkan means that you either have another overhead cleaning up at the end of each action or you write your own functionality e. g. a wrapper that you pass a function call to for the destruction of your objects. The same tutorial offers such a solution and my still limited knowledge makes me sit awestruck when i look t it. I thought it was easier, but i am just scratching the surface :-)

The sun has just set. The showers died down, for a few minutes there was a steel blue sky and the low rays blazed through the windows. Now it's cloudy again. Up on the hill where the observatories are there must be an amazing sky tonight, the clouds don't reach that high. But down here it's closing again. Cloudbase maybe 100m above my level. And it is a full moon anyway. Patience we must have :-)

Hehe. You're catching up with me. It's cloudy here, just stopped raining. So i will have to let you pass ... :-) Edit: processing. I decided to spend a little something and got me PixInsight. It is sort of a swiss army knife for DSO and has very nice and thorough documentation. I avoid tinkering with 7-9 different programs, and it runs on Linux :-). And there is a very instructive book about the software, i am learning a lot. Just sayin' ... i get nothing for it :-)

Vulkan is a pain in the ass for a newcomer to graphics programming. I can understand why OpenGL has so many followers, and it won't change in the near future. To draw a simple object on screen you need +/- 50 lines of code, including shaders, in OpenGL. And several 100 in Vulkan, without shaders. You must fill out stacks of structs, do your memory management, check every devices abilities.... It is a mess. Vulkan fits perfectly in the age of bureaucracy. I don't see Vulkan as a successor. Khronos is not explicit about it. If you just want to program a game, use OpenGL. Edit: there is for example no error checking in Vulkan. If there wasn't an API (LunarG) for it i don't think many people would touch it. eeek ... :-)

Nice ! f/6.3 or f/10 ? What was the exposure time ?

I searched "Robtics f6.3 reducer backfocus" but could not find info. But the original Celestron one showed up in the searchlist, it has 115mm, measured from chip-plane to wherever, usually the end of the thread on the reducer casing facing camerawards. So, better call robtics. Add 1mm for the pass through the filter glass, deduct the camera backfocuss and the filterwheel. Cam backfocus is the distance from camera chip to end of camera casing, some cameras have a mark at the side. Example: my reducer/flattener has 80mm backfocus when used with a focal length of 800mm. Minus 17mm camera backfocus, minus 16mm filter drawer, +1mm filter thickness makes for *scratchhead* 48 mm of rings and tubes and things to get the chip to the correct distance from the reducer. Usually not all reducers are the same and some cameras were made on monday morning, so it may be a good idea to have an element in between that you can screw in and out to vary a little bit. With the right distance the image should be ok. And ask robtics what the diameter of the corrected field without noticeable vignetting is. Answer to such questions always show me whether the person on the other end of the line know their job ;-) Tip: use distance things with a usual diameter, like M42 (2") so that the tubes will not be the cause for any vignetting and you can use them anytime you need some distance between any 2" focuser and whatever. :-) Edit: all items in the queue must have threads so that they can be screwed together without tilt. We don't want a tilted camera chip. The element used for adjusting must have a counter-ring to avoid tilt of an otherwise loose thread.

Distance chip/reducer is submillimeter work and sometimes (normally ?) manufacturers data needs ... interpretation :-) Start with the distance from the manual/tech sheet of the reducer, if you have distortion put in variations like 1mm shorter or longer and see whether it gets better. An element that allows adjustment is a nice idea. I can take a photo if you like ? Still cloudy here, showers out over the sea .... :-/

Well, i don't like the fact. Lightweights. Others drop landers on Mars. I hope nobody had a foot under it.