Starship Asterisk*

Comet ZTF over Mount Etna

Explanation: Comet-like plumes are blowing over the volcanic peaks of Mount Etna in this wintry mountain-and-skyscape from planet Earth. The stacked and blended combination of individual exposures recorded during the cold night of January 23, also capture naked-eye Comet ZTF just above Etna's snowy slopes. Of course increasing sunlight and the solar wind are responsible for the comet's greenish coma and broad dusty tail. This weekend Comet ZTF is dashing across northern skies between north star Polaris and the Big Dipper. From a dark site you can only just spot it as a fuzzy patch though. That's still an impressive achievement if you consider you are gazing at a visitor from the distant Oort cloud with your own eyes. But binoculars or a small telescope will make for an even more enjoyable view of this Comet ZTF in the coming days.

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I wonder if the comet's distance is geometric mean of the volcanos' and stars' distances… or larger, or smaller

Beautiful APOD, but... where are we?


No, I don't mean where Mount Etna is, because I can find it on a map. I mean, where in the sky are we? Can we give even a single star that we can see in the APOD a designation?


Let's see. Just above the valley between the two mountains, there is an orange star. It is the brightest orange star in the picture. And just above the mountain top on the right, there is a group of three white stars. Admittedly the middle one (the faintest one) looks a little bit yellow.

Between the bright orange star and the group of three white stars, there is another white (or slightly yellow) star. Some distance to the right of the group of three stars, there is another, fainter, orange star.

Does anyone recognize this star pattern? Because I don't. Can you find it in Petr Horálek's excellent image? Because I can't.

Admittedly, the orientation of the comet is different in the two images. Perhaps you, Victor, can create an overlay? But we must remember that the picture of the comet in the APOD was taken on January 23, and Petr Horálek's image was taken on January 26.

P.S. In Petr Horálek's beautiful image, the comet is located immediately to the right (or lower right) of an orange star. I think this star is RR UMi, or HD 132813. Just below the comet is another orange star, which I think is HD 131444. The comet's antitail is passing between these two orange stars, and the antitail seems to be "reaching out and almost touching" a yellowish star to the left, which I think is HD 133229.

Ann

Ann wrote: ↑Sat Jan 28, 2023 6:30 am Beautiful APOD, but... where are we?

Does anyone recognize this star pattern? Because I don't. Can you find it in Petr Horálek's excellent image? Because I can't.

Ann

The position of the comet is consistent with about 22:30 UT on 23-January-2023.

The brightish star between the coma and the mountain is HD 136494; below right of that is HD136577.

The brightish reddish star above the midpoint between the mountain peaks is HD 138265.

The tight arc of three stars in between the previous star and the coma is, left-to-right, HD 136882, SAO 16696, and HD 136848.

The bright star Edasich (Iota Draconis) is behind the top of the mountain below the comet.

In Petr Horálek's image, Edasich is to the left of the comet, near the edge of the frame.

Joe

I would give it a look but as usual when astronomical phenomena appear the sky is cloudy since and for weeks. I should take the hint and abandon all astronomical interest...

Beautiful!
Someone can write the technical data? Exposure time, etc.? Thank you!

Joe Stieber wrote: ↑Sat Jan 28, 2023 8:02 am

Ann wrote: ↑Sat Jan 28, 2023 6:30 am Beautiful APOD, but... where are we?

Does anyone recognize this star pattern? Because I don't. Can you find it in Petr Horálek's excellent image? Because I can't.

Ann

The position of the comet is consistent with about 22:30 UT on 23-January-2023.

The brightish star between the coma and the mountain is HD 136494; below right of that is HD136577.

The brightish reddish star above the midpoint between the mountain peaks is HD 138265.

The tight arc of three stars in between the previous star and the coma is, left-to-right, HD 136882, SAO 16696, and HD 136848.

The bright star Edasich (Iota Draconis) is behind the top of the mountain below the comet.

In Petr Horálek's image, Edasich is to the left of the comet, near the edge of the frame.

Joe

Thanks a billion, Joe!

Ann

Comet 2022 E3 Above Snowy Mount Etna

Perhaps it is not wrong to say that comets are the most fascinating objects in the sky. Although in the past they have been interpreted as signs that heralded possible misfortune, today we know that they are objects mainly made up of ice, dust and rocks. It was Giotto who give us a different image by frescoing a comet in the Adoration of the Magi in the Scrovegni chapel in 1303. Since then, this representation has remained imprinted in the collective memory to the point of identifying the guiding star of the magi with the star known as the "comet". several elements contribute to the fascination of these objects: certainly the rarity with which comets appear in the sky, their difficulty in being seen with the naked eye but above all the beauty of the tail and the crown when they manage to be observed among the infinite stars of the firmament Today we are lucky enough to be able to witness the spectacle of comet 2022 E3 (ZTF) which is located near the north celestial pole. It is not easy to admire it but it is enough to have binoculars and a little patience that it will be possible to distinguish the glow of its hair and its tail. Animated by the desire to photograph it, I took advantage of the only night with clear skies that occurred in this last ten days of January. My destination? Snowy Etna! Although it was not difficult to reach the position from which to resume the comet, the atmospheric conditions were certainly prohibitive. During the night the temperature dropped to -8°C at an altitude of 2000mt, an exceptionally cold temperature for Sicily! However, the landscape was breathtaking: an expanse of soft snow disturbed only by some fox and rabbit footprints. The branches of the trees bent under the weight of the snow but, above all, the South East crater was completely covered in snow. Its view is breathtaking, expressing, in a single image, a feeling of strength and delicacy. Looking at it, it is possible to see its internal walls through the fracture that caused part of the conical building to collapse. Some hot spots appear in the dark: they are fumaroles from which volcanic vapors come out... and in all this, the beauty of the sky with the splendid comet rising from the side of the volcano. It shines thanks to a beautiful turquoise green crown and is embellished with a long tail and a small anticoda and hundreds of stars that act as a probe in the sky.

Technical info:
Canon 6d, Sigma 150-600 mm @300mm, f/7.1,
Landscape: 2 shots, iso 320, 180 sec
Sky: 27 tracked shots, iso 3200, 45 sec, total integration time: 1215 sec, Fornax Mount Lighttrack II + flat field + dark flat field + dark frame
Location: piano vetore - mount etna
Same focal lenght, same position apart from the rotation of the astro tracker.
I am availble for any other clarification.

Clear skies
Dario

It's a clear photo composition with the comet too big and too close to the horizon. Shame for this choice

carocicosta@gmail.com wrote: ↑Sat Jan 28, 2023 4:19 pm It's a clear photo composition with the comet too big and too close to the horizon. Shame for this choice

You don't understand the nature of imaging.

It is obviously a composite, as are virtually all astronomical images. The landscape and sky were shot at the same focal length, and close to the same time, which means the framing and scale is accurate.

The apparent size of the comet with respect to the landscape is determined by the focal length of the imaging system and the distance between the horizon and the imager.

let's talk constructively.

the proprotions depend on the focal lenght and distances.
Please fidn attached the planning i did for this image in planit pro.
It is self explaning.

https://www.dariogiannobile.com/articles/e55407d7f

Dario -- thank you for adding the very enlightening notes.
This is indeed a lovely combination of art and science, suitable for framing in a gallery (or in a chapel).

dario giannobile wrote: ↑Sat Jan 28, 2023 5:47 pm let's talk constructively.

the proprotions depend on the focal lenght and distances.
Please fidn attached the planning i did for this image in planit pro.
It is self explaning.

https://www.dariogiannobile.com/articles/e55407d7f

"Proprotions"? Had me thinking I needed to learn yet another astrophotographic term. It then hit me you meant "proportions"

And now for something less enlightening... For some reason, the words of this APOD reminded me of a song, with the lyrics changed:

"Sunlight on my nucleus makes my coma / Sunwind on my dust doth stream my tail", etc,. Sung to the tune of "Sunshine on My Shoulders" by John Denver.

https://www.musixmatch.com/lyrics/John-Denver/Sunshine-on-My-Shoulders wrote:
Sunshine On My Shoulders
John Denver

Sunshine on my shoulders makes me happy
Sunshine in my eyes can make me cry
Sunshine on the water looks so lovely
Sunshine almost always makes me high
...etc....

Anyone else notice the two red "stars" inhabiting the caldera (if that's the right term)?


[ EDIT: Oh, and I missed 5 more to the left! ]

`i think this photo is fantastic! JMHO! APOD does a beautiful job!

johnnydeep wrote: ↑Sat Jan 28, 2023 10:00 pm Anyone else notice the two red "stars" inhabiting the caldera (if that's the right term)?

mount etna winter closup with lava.png

[ EDIT: Oh, and I missed 5 more to the left! ]

Nice. I hadn't noticed. The note by Dario mentioned the fumaroles, but that does not imply that there is visible lava, which it seems you have spotted.