APOD: Ghirigori - Star Scribbles (2023 Aug 12)

[APOD Robot]

Ghirigori - Star Scribbles

Explanation: It's fun to scribble on the canvas of the sky. You can use a creative photographic technique to cause the light of point-like stars to dance across a digital image by tapping lightly on the telescope while making an exposure. The result will be a squiggly line traced by the star (or two squiggles traced by binary stars) that can reveal the star's color. Colorful lines, dubbed Ghirigori, made from stars found in the northern sky constellations Bootes, Corona Borealis, Ophiucus, and Coma Berenices, are captured in this artistic mosaic. The 25 stars creating the varied and colorful squiggles are identified around the border. Of course, temperature determines the color of a star. While whitish stars tend to be close to the Sun's temperature, stars with bluer hues are hotter, and yellow and red colors are cooler than the Sun.

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[Ann]

Ghirigori - Star Scribbles. Image Credit & Copyright: Paolo Palma

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Nice, really! It's a pretty striking image and a lot of fun, too. I really like how red and bluish components of some double stars scribble identically shaped but differently colored doodles in the APOD!

But me being me, I wish they had imaged a really blue star, too. I mean a star with a negative B-V index. Such stars don't exist in the hopeless constellation of Bootes , but Corona Borealis and Ophiuchi offer a few. Such as Iota Ophiuchi, Theta Corona Borealis and really very blue Theta Ophiuchi.

The brightest blue star here is Theta Ophiuchi. Image credit: Eckhard Slawik.

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It would have been a lot of fun to see Theta Ophiuchi scribble its signature on the canvas of Ghirigori!

Ann

[PaoloPalma]

Dear Ann, thank you

The stars I have selected for the Ghirigori are those that show the highest colour contrast in visual observation. That is why they are often doubles or tris of perspective stars. I have not selected stars solely on the basis of the B-V index also because bright stars, particularly blue stars, show little colour in visual observation, even more so if they are single and have no nearby companion to compare them with.

If you like you can find the shades of the stars you mentioned among the colour constellation mosaics I have constructed defocusing all the stars up to magn. +5 of Italian latitude:

http://www.unsaltonelcielo.it/costellazioni-a-colori/

Thank you for the idea: maybe one day in the future I will do Ghirigori of stars just based on their B-V index and see the result

[Ann]

Dear Ann, thank you

The stars I have selected for the Ghirigori are those that show the highest colour contrast in visual observation. That is why they are often doubles or tris of perspective stars. I have not selected stars solely on the basis of the B-V index also because bright stars, particularly blue stars, show little colour in visual observation, even more so if they are single and have no nearby companion to compare them with.

If you like you can find the shades of the stars you mentioned among the colour constellation mosaics I have constructed defocusing all the stars up to magn. +5 of Italian latitude:

http://www.unsaltonelcielo.it/costellazioni-a-colori/

Thank you for the idea: maybe one day in the future I will do Ghirigori of stars just based on their B-V index and see the result

If you are looking for color-contrast stars, then I really recommend blue-white B2 π⁵ Orionis, which forms a wide double with orange M1-type 5 Orionis. Nearby, you find red carbon star W Orionis.

Blue π5 Orionis, orange 5 Orionis and red W Orionis.
Image credit: Genevieve de Messeries/Shutterstock

I also very much recommend 30 and 31 Cygni:

31 Cygni is an orange K-type giant, 30 Cygni (at upper right) is an aqua-colored A-type star, and HD 192579 (lower left) is a blue B-type star.

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Oh, and I recommend Eta Cassiopeiae as well, a sunlike star with a red dwarf companion.

Sunlike star Eta Cassiopeiae and its red dwarf companion.
Image credit: Index Hamal.

You should be able to create colorful star scribbles indeed using these brightly colored stars!

Ann

[PaoloPalma]

Dear Ann

I am pleased that you know these pairs of coloured stars and the carbon star W Orionis too. Not far from 30 Cygni there is also U Cygni often impressive for its ruby colour.

Over 10 years ago I selected most of the most colourful stars in the sky visible with a 30cm telescope. There are about 400 of them, singles, doubles and triple stars, all of which I will photograph as Ghirigori a little at a time over the next few months. And those you just mentioned are also present.

Here you can find more informations: https://shorturl.at/ijnDZ

So far I have photographed about 100 of them. But I have only published 2 mosaics with a total of 50 objects.

I hope you will like them

[Ann]

Dear Ann

I am pleased that you know these pairs of coloured stars and the carbon star W Orionis too. Not far from 30 Cygni there is also U Cygni often impressive for its ruby colour.

Over 10 years ago I selected most of the most colourful stars in the sky visible with a 30cm telescope. There are about 400 of them, singles, doubles and triple stars, all of which I will photograph as Ghirigori a little at a time over the next few months. And those you just mentioned are also present.

Here you can find more informations: https://shorturl.at/ijnDZ

So far I have photographed about 100 of them. But I have only published 2 mosaics with a total of 50 objects.

I hope you will like them

Thanks Paolo, how interesting!

I wasn't able to read much of what you sent me, since it appears to be in Italian, but I could certainly look at the pictures. That's very interesting indeed!

I see that you have already photographed 30 and 31 Cygni. Unfortunately blue HD 192579 (or SAO 49338) doesn't show up well. Its color was so impressive when I observed it through a telescope many years ago.

I have a question for you. I found a nice blue star among your stellar portraits, but I don't understand its designation, STF 2751. What does STF stand for?

Ann

[canopia]

In the legend, the scribbles labeled V CrB and V Oph look to be the same image.

Meanwhile, the third scribble from left in the top row of the main image does not have a labeled version.

Tunç Tezel

[PaoloPalma]

Dear Tunç Tezel

Nice to meet you
You are right. In the legend I put twice the scribble of V Crb by mistake. The scribble of V Oph is the third from left in the top as you mention.

Thank you for pointing it out to me

[orin stepanek]

Amazing what a little jiggle or an upside down tree can do!

[johnnydeep]

So, why are they "dubbed ghirigori" I ask google? Well, it's because 'ghirigori' is apparently Italian for 'scribble'!

From https://dictionary.reverso.net/italian- ... /ghirigori

ghirigoro
(scarabocchio) doodle, scribble , (arabesco) flourish

Of from https://dictionary.cambridge.org/dictio ... /ghirigoro

ghirigoro

noun, [ masculine ] /ɡiri'ɡɔro/

doodle, scribble

"fare dei ghirigori" - to draw doodles

Synonym - scarabocchio

[PaoloPalma]

Yes, exactly. Unfortunately, the published description is shorter than the one I suggested. I chose the word Ghirigori because as well as being the first thing that these colourful lines remember, the term can well suggest the lightness of their visual contemplation and the playful aspect of their shooting.

[PaoloPalma]

Dear Ann

I am pleased that you know these pairs of coloured stars and the carbon star W Orionis too. Not far from 30 Cygni there is also U Cygni often impressive for its ruby colour.

Over 10 years ago I selected most of the most colourful stars in the sky visible with a 30cm telescope. There are about 400 of them, singles, doubles and triple stars, all of which I will photograph as Ghirigori a little at a time over the next few months. And those you just mentioned are also present.

Here you can find more informations: https://shorturl.at/ijnDZ

So far I have photographed about 100 of them. But I have only published 2 mosaics with a total of 50 objects.

I hope you will like them

Thanks Paolo, how interesting!

I wasn't able to read much of what you sent me, since it appears to be in Italian, but I could certainly look at the pictures. That's very interesting indeed!

I see that you have already photographed 30 and 31 Cygni. Unfortunately blue HD 192579 (or SAO 49338) doesn't show up well. Its color was so impressive when I observed it through a telescope many years ago.

I have a question for you. I found a nice blue star among your stellar portraits, but I don't understand its designation, STF 2751. What does STF stand for?

Ann

Dear ann

I was hoping you could translate it online. You will see the new photo of 31 Cygni when I will post its Ghirigoro in the future.

STF is the abbreviation for the catalogue of double stars published by Georg Wilhelm von Struve. The brightest star is HD 200614.

[Ann]

Dear Ann

I am pleased that you know these pairs of coloured stars and the carbon star W Orionis too. Not far from 30 Cygni there is also U Cygni often impressive for its ruby colour.

Over 10 years ago I selected most of the most colourful stars in the sky visible with a 30cm telescope. There are about 400 of them, singles, doubles and triple stars, all of which I will photograph as Ghirigori a little at a time over the next few months. And those you just mentioned are also present.

Here you can find more informations: https://shorturl.at/ijnDZ

So far I have photographed about 100 of them. But I have only published 2 mosaics with a total of 50 objects.

I hope you will like them

Thanks Paolo, how interesting!

I wasn't able to read much of what you sent me, since it appears to be in Italian, but I could certainly look at the pictures. That's very interesting indeed!

I see that you have already photographed 30 and 31 Cygni. Unfortunately blue HD 192579 (or SAO 49338) doesn't show up well. Its color was so impressive when I observed it through a telescope many years ago.

I have a question for you. I found a nice blue star among your stellar portraits, but I don't understand its designation, STF 2751. What does STF stand for?

Ann

Dear ann

I was hoping you could translate it online. You will see the new photo of 31 Cygni when I will post its Ghirigoro in the future.

STF is the abbreviation for the catalogue of double stars published by Georg Wilhelm von Struve. The brightest star is HD 200614.

Thanks, Paolo! I very much look forward to your new photo of 31 Cygni!

As for translating texts online, I can do it, of course, with the help of Google. I just lost interest in that several years ago when I used Google to translate a text in German into English. The text was about the mighty LBV star Eta Carinae. Well, Google translated "Stern" (which is German for "star") into "asterisk"! That kind of killed my enthusiasm for translating texts via Google!

Eta Carinae. Image credit: NASA, ESA, N. Smith (University of Arizona, Tucson), and J. Morse (BoldlyGo Institute, New York)

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An asterisk.

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Eta Carinae is an asterisk? I think not!!!

Ann