Starship Asterisk*

Yet another fine lecture from Ann! Thank you for text and images!

In this picture I see little to no asymmetry in the craters that I would expect if the impactor hit at an angle other than 90 degrees to the surface. Now that I think of it, this seems to be common to most of the pictures I have seen of other cratered surfaces. Am I missing something? Or is it the ...

It is Jupiter, of course! I seached for it in the 2024 sky, but the film is from 2023.

Sputnik2Mars2020 wrote: ↑Mon Aug 26, 2024 3:31 pm Thanks Holger,
Are you seeing the small moving object?

Yes, I see it now, moving towards the Pleiades. It is probably an artificial satellite.
But what is the bright stationary object?

This is what I have been able to identify: 0:20 - 0:23: Altair in Aquila at top 0:24 - 0:29: Hyades at top, Orion at bottom 0:29 - 0:33: Pleiades near center with Hyades below, bright object not identified. 0:33 - 0:40: Ditto. 0:54 - 0:59: Ditto. Bright object seems static 0:40 - 0:43: Ursa Minor at...

As has been explained the glory is not a particular object in the sky, but the effect of backscattering of light rays from the sun from a particular set of raindrops in the sky in front and below you. The same can be said about the rainbow: Every person observes their own rainbow produced by reflect...

Is that really a fog bow? To me it looks just as some background clouds. Below is an image of a fogbow photographed in the Greenland Sea in September 2023. "Fun fact" about glories: If you see a glory and are acompagnied by other people, you will only see a glory around your own head. 2023...

As a courtesy to an APOD contributor that person’s name should be spelled correctly. From the last month:

Contributor Character ASCII Unicode
Jürgen Stein ü 0252 00FC
Göran Strand ö 0246 00F6
Tunç Tezel ç 0231 00E7

It’s not that difficult.

Some parts of the name puzzle me. "JADES" is an acronym for "JWST Advanced Deep Extragalactic Survey". But what dose "GS" mean? And with a redshift of z = 14.32 why the "0" in "z14-0"? The previous record holder, JADES-GS-z13-0, has a redshift of 13....

It has been said of the brilliant Indian mathematician Ramanujan that every natural number, for instance 1729, was a friend of his (If you have not heard of him, look him up in Wikipedia ).

Likewise, it seems to me that every galaxy in the Messier and NGC catalogues is a friend of Ann.

"At that distance, IC 1795 would span about 70 light-years across." I don't understand how a width, expressed here in absolute units, is related to distance. Look at the illustration below: Fig003_AngularDiameter.jpg A distant more or less (!) spherical object with a radius of R will at a...

Is that Cassiopeia's W near center? Probably not near center, but Cassiopeia should be in the picture. I definitely couldn't spot the familiar W. Ann Cassiopeia is in the picture. Look at the annotated version mentioned in the explanation. The image is a another masterpiece by Tunç Tezel. APOD shou...

And now go outside and look at the clouds to find one shaped as an elephant or a piggy.

A similar photograph from Alaska was published in the APOD of 2016 February 8 . The overlaid picture shows constellations and stars also in Chinese. All of them use three Chinese characters. I wonder what they mean. When pronounced would they sound like the Latin designations or are they poetic desc...

If you were 60 light years away from Thor's Helmet, would you be able to see this amazing vista with your own eyes? It would be invisible to the naked eye at any distance. If you move towards it, it also increases its extension in the sky. It wouldn't be invisible. NGC 2359 is an accessible target ...

JimB wrote: ↑Tue Jan 09, 2024 9:51 am If you were 60 light years away from Thor's Helmet, would you be able to see this amazing vista with your own eyes?

It would be invisible to the naked eye at any distance. If you move towards it, it also increases its extension in the sky.

How far away is the boy? Measuring on the image on my screen the diameter of the Sun is 220 mm, corresponding to an angle of about 30′ or 0.50°. The image height of the boy is 70 mm, so he extends an angle of 70/220∙0.50° = 0.159°. Estimating his physical height to be 160 cm or 1.60 m, his distance ...

And the silhouette of the Emu in the Sky is shown rather well, too.

johnnydeep wrote: just copy/paste Thank you, that works! I tried that with a Greek "nu", but was unhappy, because it came out resembling a Latin "v". I should have known better! This leaves the question why "char" does not deliver for instance a degreen symbol, º, as ad...

johhnydeep writes: 1. Ok, the absorption lines are caused by the presence of various elements in the Sun's atmosphere that absorb the corresponding frequencies of a continuous spectrum light, resulting in dark lines, meaning the photons absorbed never get to us. But what happens to those photons? I ...

Technical question : Is it not possible to write Greek characters on Asterisk? Or Unicode? I tried to use the "char" button, but I cannot get it to work: [char]beta[/char] [char]deg[/char] produces this output: beta deg , even though the last example is suggested by the "char" b...

Ann writes: This is what happens after a hydrogen atom has become ionized : https://upload.wikimedia.org/wikipedia/commons/thumb/9/93/Bohr_atom_model.svg/1200px-Bohr_atom_model.svg.png ... When an energetic photon from an O-type star hits a hydrogen atom, the electron will gain so much energy from t...

Also visible in the image is the Maori non-constellation of The Emu , the flightless bird from New Zealand. It is made up not of stars, but of the dark clouds in the Milky Way. The head with the bill is seen near the top right and the body stretches all along the Milky Way, see also this identificat...

I, too, find the diffraction spikes visually disturbing, but the purpose of Webb is not to produce aestetically pleasing images. Note that there are eight spikes, six originating from the hexagonal mirrors and two more ("horizontal") from the three spokes carrying the secondary mirror. The...

NorbVor wrote: ↑Wed Feb 15, 2023 7:14 am The label "Sirius" is placed on the wrong star!

Yes, that star must be Procyon. Sirius, I think, is the bright star farther below somewhat above the large tree in the foreground. The rather bright star near the top left could be Pollux.