UmbralRaptor

Something like this? http://www.staff.science.uu.nl/~gadda001/goodtheorist/index.html

Tried that earlier in the thread. Well, after various additional attempts tonight, a 322 s image have to do for star trails. Not sure if the brightness gradient vignetting or varying sky brightness from the near-full moon. What else is left? Set a neutral density filter on top of the lens to try to increase exposure time? Improvise an r-band filter and hope for a clear moonless night in November so I can attempt an SNR 3 detection of M31? edit: There was supposed to be a flickr link in an earlier post. https://www.flickr.com/photos/39407198@N02/ edit2: Googling around for super resolution options suggests that I'd either need to code up something or buy photoshop. So much for getting a 135-180 pixel moon image.

It's starting to feel like there's no reason to attempt [astro]photography without at least a few kilobucks of gear. Currently I'm using a Canon SD1100 IS with CHDK. Starfields are... problematic. Lots of intermediate exposure lengths seem to have jitter, despite leaning the camera on objects, or setting it down with a 2 or 10 second exposure delay and then stepping aside. And of course, the sky glow can be nightmarish if there are thin clouds or lots of haze. Leaving the camera facing straight up when the plane of the milky way is overhead seems to be best. My biggest success would be: That building in the way is shielding the camera from a waxing gibbous moon. I think this barely detected M13, M92, M56, and M29. If Source Extractor can deal with JPGs it might be interesting to see if it can find them? The image also split the AB-CD component of ε Lyr, but as I was at minimum zoom (f/2.8, 6.2 mm) to maximize light gathering, don't expect resolution beyond 1'/pixel. At 51s, there are noticeable (12-13 pixel, I think) star trails. Given the amount of sky glow locally (Bortle class 8-9) I'm not sure if a 5-30 minute exposure (for actual star trails) would be worthwhile. How about something brighter? It's certainly possible to get well exposed and in-focus images of the Moon, but with max zoom (f/4.9, 18.6 mm), the image scale appears to be ~20"/pixel. This does not lead to an interesting amount of detail, and practically speaking makes Venus, Jupiter, and Saturn unresolvable. Also, the red bit in the lower right is as best I can tell a bad pixel. Avoidable provided I don't aim directly at anything. Okay, let's just have the Moon as a background object for a structure? Make the very wide FOV/poor angular resolution a feature instead of a bug? The dynamic range just isn't there for both the Moon/lights and structure to be properly exposed. Now what? Only shoot during the day?

Space telescopes *are* used for planetary science (Kryten mentioned Pluto, but HST has also been used on Uranus, Neptune, and lots of asteroids and KBOs), but being able to get close does wonders for image resolution. Plus there are instruments/measurements (eg: particle detectors, magnetometers, mass spectrometers, laser altimeters) that make sense for craft doing close flybys or orbits but not ones that stay at earth.

You can convert Isp to m/s by multiplying by g because of the unit weirdness involved in how Isp is defined. For rocketry, effective exhaust velocity is more intuitive/natural, but KSP went with a wacky unit that existed in part because people thought lb*s of impulse per lb of propellant was a good idea. I would not trust any EC to Joule conversions, since last I checked, they were all over the place, and would lead to things like vehicle lights consuming kilowatts.

So no Proton or Ariane-5? Doesn't this also preclude Boeing (Delta IV) and Lockheed-Martin (Atlas V)? There will be a limit on capsule mass being low enough to fit on a Delta IV heavy. If this is problematic, I'd be flexible on allowing the Atlas V heavy, and Delta IV superheavy (3 CCBs and 3 SRB) configurations, but developing a wholly new launch vehicle is verboten. Ideally something smaller than any of those would be used, and I will violate rule 5 if it is needed to prevent the development of a new launch vehicle.. It's slightly annoying to not be able to get commercial cargo/crew going a few years earlier, but again restricting the launch vehicle options should keep costs down. Orbital assembly will be acceptable, given the increased knowledge that will be gained with the ISS. I'd rather not get deep into the design, because I am not engineer.

It's painfully close to accurate. Substantially less so than 9 years ago, given that the ISS has now generated scientific results (eg: AMS's dark matter limits), and is acting as infrastructure for commercial cargo/crew systems. That the station's lifespan has been extended, and Constellation is gone also help.

Effectively no. As K^2 mentioned, Tachyons are allowed by relativity, but not the standard model. Lasers exploit a quantum mechanical process and are useful for communication. But that's still limited by c.

I'm not comfortable throwing around things like the Rayleigh Criterion here, given the differences between gravitational lenses and normal lenses/mirrors. The detections are still not quite guaranteed, and we could have missed some. But certainly it would ease the amount of sky needed to scan.I'm not going to touch propulsion issues at the moment. Likewise, though I would expect ground based competition. Thanks. I'll have to see if I have institutional access, but since this is mainly out of curiosity, it's probably not worth putting actual money into.

The idea of using the sun's gravity as a telescope has been fairly developed, but I've been having lots of trouble finding details. (Besides how to get a probe there) Playing around with the simplified version for a point mass gets me the numbers (in terms of just under 550 AU minimum distance and ~1.5 arcsecond apparent size of the image ring) that jibe with what's found elsewhere, but I still have lots of interrelated questions: What is the width (linear and angular) of the ring? (I assume it depends on the nature of the imaging system?) How much is the image magnified and/or made brighter? Is the image ring always ~1-1.5 solar diameters for the typical 550-1000 AU distances, no matter how distant the object being magnified is? If so, does this make it unsuitable for observations of distant galaxies? Can this work for more distant stars, and if so, why isn't it already in use given that there are a number of distant (non-trivial redshift) galaxies with annoying foreground stars? And how do you deal with the sun being right in the middle of your image? A coronagraph? I suppose it's mostly a big mess of general relativity and optics that I don't have much familiarity with. Hence this being tagged as Physics instead of Sci Fi Theory. edit: Found a , and a frustratingly expensive book that likely has lots of details.

I wouldn't be surprised if a redesigned nozzle could get you 10-20 s higher vacuum Isp. That would probably cut into the TWR and sea-level Isp, though. I'd rather look towards ways to make it cheaper and at most add the ability to air-start (if possible).

We've known the approximate colors of Pluto and Charon for a number of years. eg: http://www.boulder.swri.edu/~buie/biblio/pub072.html

Since others have covered the basics, I just want to point out that the filter wheels carried by spacecraft cameras often result in *more* colors than the standard RGB. (Though chances are you'll only see a few at a time) In the case of New Horizons, it's worth noting that we already have low resolution colors, but have not recieved the vast majority of the data. That will be arriving in lossily compressed form in coming weeks-months, with the full images, etc taking a year or more.

Debian and Android. edit: as far as UIs go, i3 wm and Nova Lancher, respectively.

Are the thermometers active? They have a small drain while taking data.

Nope! There are lots of double stars where the angular separation is large enough to be quite visible in a telescope. They may also have close in companions, and there are lots of cases where two unrelated stars just happen to line up, but still...Without getting into exact stars observed, it's hard to tell if this was just visual artifacts or actual doubles/multiples.

At this time of year: M4,5,6,7,8,11,13,16,17,18,20,21,22,23,25,57,92

Since no one has mentioned it yet, averted vision. Well, some are. (eg: globular clusters are puffballs, and the emission nebulae tend to be irregularly shaped haze.) Open clusters are distinctly resolvable in binoculars, though.

The enrichment and/or reprocessing methods for Uranium-235 and Plutonium-239 can simply be run to higher enrichment levels to get weapons-grade materials. Uranium-233 can be produced from Thorium-232, so Thorium reactors can be used to produce weapons. (though with much greater difficulty) o_O That's literally the opposite of what is happening

The old hard water oceans.

It's an old joke that shows up a lot in spaceflight.

Well, last night I was up on a roof with some people viewing the Venus/Jupiter conjunction. I'm not seeing the appeal of holding a camera up to the eyepiece (Nexus 5, 25x100 binoculars) Views through a nearby 16" scope were much nicer, but I wasn't able to get any sort of image with my phone, so... At least the colors are nice with this unzoomed moon shot. edit: I suppose I should see what I can do with a 60 mm f/15 scope and a pair of 8x30 binoculars this weekend? Uh, and if anyone's in the KC area http://askc.org/

1) Kerbals respawn after a while at lower difficulties. 2) Probably there's something wonky in how the stages are laid out. We'd need to see pics (and maybe a .craft file)

It depends on design details, but essentially you invert the rocket equation, using a known ÃŽâ€V and the mass of non-payload portions of the craft to solve for the payload. Simpler designs can do it analytically, but you may need to mess around in Excel or the like for more complicated ones. I've toyed around with some analytical models. I don't suppose they can help inspire?

Well, there are a few halo stars that close, so...