Starship Asterisk*

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.

Ann, thank you for another well illustrated lecture! I found the image showing the future parts of the Local Group galaxies particularly interesting.

The "Discuss" menu item is missing on todays APOD image, which is quite impressive (the image, that is).

Ann writes: "a G2 star" "an O5 star" Yes, of course. :oops: I'am sure my English teacher taught me this many years ago, forgive an old Dane! You mention the spectacular image of the Rosetta Nebula by Jean M. Dean. I searched for her on APOD. Her image appeared in fact here in 201...

Using Wikipedia and the SIMBAD database I have identified the following stars: The brightest one in the picture is a foreground star, 12 Monocerotis, a K0 giant at a distance of 462 la with V = 5.83. The bright blue star to its right is the O4 star HD 46223 at a distance of 4680 la with V = 7.28. Th...

Ann writes:

I'm sure you're all taking notes!

Indeed, I always enjoy reading your mini-lectures with their attention to interesting details!

When seeing illustrations of this kind, I am always a little suspicious: Are the discs shown really that large? So I did a little calculation using data (in green) from the Internet: TRAPPIST system.jpg The central star has an angular diameter of about 1°, twice the value of that of the Sun as seen ...

I am intrigued with the comparison of Barnard 68 in visible and infrared light, as presented by ESO https://www.eso.org/public/images/eso0102c/ : https://cdn.eso.org/images/screen/eso0102c.jpg Background stars are heavily reddened from the passage of their light through the cloud; red colour chosen ...

When this image was posted on APOD several years ago, I had the same problems with it as Ann. An earlier post http://asterisk.apod.com/viewtopic.php?t=41170 suggests that the peak is ”Pilan” looking over Laupstad in the Austnesfjord. According to https://mapcarta.com/N6391608680 Pilan’s position is ...

Very interesting comparison, Ann, thank you for your effort. Your desciptions helped finding the same features on different images.

The extreme projection used makes it difficult to identify stars. I beleive I have found the pair Alpha and Beta Centauri at about 2 o'clock, the Coalsack with the Southern Cross (upside down :wink:) at 1 o'clock, the Eta Carinae nebula in the Milky Way at 12 o'clock and above it, close to the upper...

Much attention to details has been put into this excellent picture. Note that the star labels are written with colors simulating the stars'.