Starship Asterisk*

This is a 10% Moon that is 2° above the horizon. The Sun is 21° below the horizon, so just out of astronomical twilight and it should not be contributing significant light. I would be curious to know the technical details of the image. I don't think it could be achieved without some kind of HDR pro...

This is a 10% Moon that is 2° above the horizon. The Sun is 21° below the horizon, so just out of astronomical twilight and it should not be contributing significant light. I would be curious to know the technical details of the image. I don't think it could be achieved without some kind of HDR pro...

looked up 1) date and time = December 15, 2023 at 18:52 pm 2) stellarium Cathedral, Mountain, Moon..jpg Cathedral, Mountain, Moon-..jpg https://asterisk.apod.com/download/file.php?id=48994&t=1 Moon is 9° above (+09°01'15.1") and Phase=9%, Sun is 11° below (-10°55'12.6") Twilight it is

Distance. Monviso is far enough from the camera that the air scatter (chiaroscuro) between them is saturated, or nearly so. (playing the kid who could have asked the kid's question) I take it you assume that the light scattered is not coming from Moon (and this must be so seeing the shine is blue r...

why the dark blue shine of the night sky looks almost the same in front of Monviso and beside it? Distance. Monviso is far enough from the camera that the air scatter (chiaroscuro) between them is saturated, or nearly so. (playing the kid who could have asked the kid's question) I take it you assum...

kid's question: why the dark blue shine of the night sky looks almost the same in front of Monviso and beside it?

I didn't say that photons can't be affected, only that they only can travel in a straight line (geodesic) which they cannot be deviated from. Which is why scattering involves the replacement of one photon with another. So is a photon that drops in energy while traveling along a space-time geodesic ...

Elastic scattering does not result in the same photon continuing. QM describes that scattering as the annihilation of one and the creation of another. That is different from an atom absorbing a photon and emitting another. Quantum Mechanics + Quantum Field Theory may add virtual particles every way...

2) Well, sure the extra length isn't "statistically significant", but the path the reflected photon takes (ignoring particle/wave duality, etc) is certainly not shorter than the path a "direct" photon takes! And in reply to Chris, for photons being absorbed and reemitted (the &q...

A December Summer Night (2023 Dec 23)..jpgmy second question: why some 8 minute exposure arcs are thin lines but others are parallelograms? offtopic To my eye there is some resemblance between the fuzzy reflections and the the Sparkler Galaxy :wink: https://asterisk.apod.com/download/file.php?id=48...

https://asterisk.apod.com/download/file.php?id=48983&t=1 Well, if you want to be really technical, the photon that comes from Alpha Centauri never makes it to the sensor at all, regardless of the path it takes. That photon is scattered (probably many times) by air, by water, by camera optics. A...

my second question: why some 8 minute exposure arcs are thin lines but others are parallelograms?

my question: the Solar system is peculiar-moving at the speed of 20 km/s toward an apex between Lyra and Hercules.
Now does the interstellar media headwind play any part in this night sky shine? (I know this APOD says it is just Sun's stellar wind and light)

a kid's question: is the path covered by a photon from Alpha Centauri any longer if that photon is registered by the sensor in the waters' part of the scene?

Please who can make a good job of fitting MIRI to NIRCAM? https://esawebb.org/images/comparisons/weic2330/ wow Now I can fit X-ray with neutron star labelled… and it can't be seen in either NIRCAM nor MIRI :( And it is not inside the Green Monster Cas A X-.jpg Cas A MIRI-.jpg Cas A NIRCAM-.jpg X-ra...

What are the purple bubbles? Any idea? Screenshot-20231213-212535[1].png https://i.ibb.co/LSzBhCZ/Screenshot-20231213-212535.png Seems intriguing to me. JWST team writes that this circular spots is all that's left of the Green Monster's spotted skin, seen in MIRI Please who can make a good job of f...

I think that's it. I've seen plenty of nighttime pictures taken when there's a full-ish Moon, and they are indistinguishable from daytime images. so you don't think that some brownness of Moon is dimming the sky shine and therefore deepening all the shadows (in long exposure colourful nighttime sho...

offtopic about colourful scenes at night I challenge everybody to solve this mystery. If you zoom in this APOD and see just the bridge, the water and the trees, why do you still feel that it is night? There are no (sharp) shadows in the APOD, and yet the light is unevenly distributed. The bridge is...

Ann wrote: ↑Tue Dec 12, 2023 12:43 pm There is a Swedish saying - it might be an American saying too, for all I know: All cats are gray at night.
Ann

ok, I apply saturation -50/100 (after moonification)

Here is my attempt to photoshop this APOD into a day-feeling scene: https://asterisk.apod.com/download/file.php?id=48933&t=1 All it took was to apply gamma=2 to the green channel and gamma=3 to the blue one I still think that looks like a night scene. The reason is that the colors are so washed...

it would take a logarithmic scale to map the distances of every labelled thing in this APOD. The same goes for their lifetimes; those are like this: Aurora < Norwegian Sea < Big Dipper Stars < Mars, Pleiades, Milky Way, Andromeda 100 microyears < 10 megayears < 1 gigayear < 10 gigayears

Ann wrote: ↑Mon Dec 11, 2023 7:07 am Bright day 25 November 2023.jpg

Ann

nightification gamma .4 for the red chammel, .2 for the green channel, .1 for the blue channel

let me try it the other way round, to photoshop a daytime scene

into a nightish-feeling one

The Sun may be undergoing minimums and maximums (which is caused by its magnetism), but it still darn quiet for a star of its class! https://www.syfy.com/sites/syfy/files/styles/scale_600/public/sun_brightness_vs_star.jpg Ann what are the "365 solar-type stars"? Are they the same mass and...

offtopic about colourful scenes at night I challenge everybody to solve this mystery. If you zoom in this APOD and see just the bridge, the water and the trees, why do you still feel that it is night? It has to do with the quality of the light. Is the light "evenly distributed", as it is ...