Starship Asterisk*

wow ... you mean there is actually a nebula without a cutsie name attached? you know, the wizard nebula? the heart and soul nebula? the owl nebula? the eskimo nebula? is that even possible? someone has to glom onto this prize bit of unnamed celestial real estate and slap a stupid "looks like a ...

this is a great topic, glad to see science interest win out with a pretty picture. what is the trend in distance measurement? i think the estimated distance to the andromeda galaxy has been getting smaller, from the estimated 2 million light years distance i remember as a teenager to the circa 800K ...

what is the "viewing clarity" of a camera? i've heard of aperture, focal length, focal ratio, magnification, transmission, resolution and even weird stuff like strehl ratio and zernicke zones ... but viewing clarity? i really have to guess. is that like the weather? the camera doesn't have...

point of english usage: "light" is *visible* electromagnetic radiation. the standard of light is the human eye and the radiation it can detect in most situations. it is incorrect to use the phrase "infrared light" for the same reason it's incorrect to use the terms "xray lig...

At around mag 17, this star would generally be considered pretty bright. It is orders of magnitude brighter than the SDSS detection limit. thanks, chris. as a visual astronomer i guess i work in a shallower pond. what then is a "faint" star -- mag. 20? how many stars are available to scru...

this star is very faint ... i cannot find it in the millennium star atlas, not even in stellarium, so it must be below v.mag. 15. my question is how it was identified in the first place, given the time required for even a large aperture scope to collect enough light to do the detailed spectroscopy. ...

looks like another perfect evening for astronomy.

the APOD editorial team has really slipped down the slope of pretty pictures in recent months. i'd prefer that the team first asked themselves, "what specifically does this picture of the day have to do with ... astronomy?"

relevance to astronomy: 0%
chances similar technology will be deployed on mars within a century: 0%
out of office messages from APOD selection committee: 100%

For my money Vesta is a dwarf planet==it has hydrostatic equilibrium. The designation "dwarf planet" is ambiguous enough for Vesta's inclusion in that class. Besides, Vesta is closer to Earth {and more Grecoroman} to be a dwarf planet. Let us make up for poor redenominated Pluto!!! in my ...

i've never heard of a space pump before. how long does it take to pump a cubic meter of space?

minor but important point of language: "light" is radiation that can stimulate the human eye to produce a visual sensation. there is no such thing as "xray light" or "microwave light", because these are invisible -- unless one wants to admit "heat light" and &...

the half dozen or so unusually bright (large) xray points, excluding the population at the nucleus of the galaxy, are probably multiple, overlapping xray binary signals from inside globular clusters.

i love national geographic cover art, i really do. but whither apod? readers here often ask some pretty arcane technical questions. but the topics are *scientific*, not "wow, sure is purdy!" why not use the five weekday window as a time machine? * five shots of open star clusters, from the...

very nice. but the geometry here actually comes straight out of the renaissance: parallel rays appear to converge to a point, known as the vanishing point. this is a classic central perspective projection. there is an intriguing and turbulent (fluid and chaotically mixed) boundary between art and sc...

"frequently difficult to test?" UNIFORMLY IMPOSSIBLE to test. i can acknowledge but not approve the contemporary trend in physics to dawdle in the imaginary (string theory) or to hypothesize physical facts that can be experimentally "studied" only in computer simulations (dark ma...

the photo discussion forum would be a great place to post the celestial coordinates and visual magnitude of the object, so that amateur astronomers can place it in relation to the galactic background and the range of objects they are able to see. i infer from its "recently discovered status&quo...

the most striking details about many nebula photographs are the structure shapes that strongly resemble media mixture -- smoke tendrils in air, dye diffusing in water, or bok globules that seem to be the innards of a lava lamp. these complex shapes often have sharply defined boundaries, strong visua...

i look at that photo and my visceral first reaction as an astronomer? LIGHT POLLUTION! it's everywhere.

"much less dense than earth's atmosphere" ... at what altitude? sea level? 50 miles?

i didn't vote for this image and regret that it was posted because it grossly misrepresents both the relative sizes of the earth and moon (because the moon has a higher albedo) and grossly misrepresents the earth/moon distance relative to size. image size of earth = 11 pixels image size of moon = 5 ...

one aspect of the rainbow geometry: for each rainbow observer, the center of the circle implied by the rainbow arc is always at the solar shadow of the observation point, which in this case appears to be the top of the observation dome shadow cast on the ground, just below the wall of the small whit...

it's a wasp, probably a yellowjacket. observe the downward curl in the tips of the antennae. the head and thoracic segment are greatly enlarged in comparison to the abdomen due to extreme foreshortening. but it's a wasp.

i recommend the photos posted on a page linked from a page linked in the photo caption ... details of the "tentacles":

http://www-xray.ast.cam.ac.uk/papers/ngc1275/

This image has been widely discussed in the meteoritics community. The consensus (unanimous as far as I've seen) is that the camera got jarred by wind or maybe an animal. The same effect has been seen on other images where that happened. That doesn't jive with larger bolides pretty much all observe...

JLo, exSquid: the "second meteor" is an enlarged inset image of the first (there is only one meteor), and the camera is on a clock drive, which tracks the moving stars. the useful point of information would be to calculate the spatial variance implied by the "wobble". an eyeball ...