Stellarium in a multimedia installation

[Alessandro Fogar]

Hi,

let me ask a question...

I'm an artist and a software developer.

I'm currently writing a new installation using stellar data.  

The idea is to sonify these data using Supercollider.

https://supercollider.github.io/

What I would like to do is to obtain data of celestial objects (stars, planets, etc.) intersecting  a meridian and sending them in some way to the sonification patch.

If possible in real time (i.e. with Stellarium running and sending the data).

Before reinventing the wheel I'm asking for some help...

Is there perhaps a plugin or a script I could use ?

I'm aware of Stellar Command but at the moment it is not an option, no internet connection in the installation site.

Many thanks in advance

Best

--

Alessandro Fogar

http://www.fogar.it

[Georg Zotti]

Hi!

I like the idea of doing something artistic, like sonifications, especially in a ready-made downloadable package with simple instructions that can be deployed by people not familiar with SC. (This looks quite impressive in itself, but is difficult for beginners with too little time and zero background in electronic music.) However, there is no function in Stellarium to trigger a signal on "meridian passage of a star brighter than mag X". You would have to write a plugin with a private list of interesting objects (like 1000 or 2500 brightest stars, and the planets, maybe 4 Galilean satellites of Jupiter (play with visibility, transits, shadows,...), and some special configuration for the orientation of the Milky Way? Also pulsars with rotation frequencies are available...) and frequently test the azimuth of all objects of this list. Building a dynamical list on a frame-by-frame basis may be much too slow.

If you want to go through all stars instead, look into SpecialZoneArray<Star>::draw() in ZoneArray.cpp. But do not change this function directly, rather take the relevant parts to read the data into your plugin and instead of rendering, emit your sound commands. 

[Angelo Fraietta]

You can download the data beforehand using VizieR, save it to file, and then probe that for RA/Dec in Stellarium (you can get all that using StellarCommand also and send to SC using OSC)

 

This piece was done with no internet at performance using pre-loaded VzieR tables using Stellar Command.

https://vimeo.com/355694234

[Angelo Fraietta]

You can download the data beforehand using VizieR, save it to file, and then probe that with RA/Dec in Stellarium (you can get all that using StellarCommand also) 

This was done with no internet at performance.

https://vimeo.com/355694234

On Thu, 29 Apr 2021 at 5:10 pm, Angelo Fraietta <ang...@smartcontroller.com.au> wrote:

Yes, i did it at Nime.  I have a library for connecting between stellarium and vizier and sonifying it

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Dr Angelo Fraietta
A.Eng, A.Mus.A, BA(Hons), PhD.

Home Page

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There are those who seek knowledge for the sake of knowledge - that is CURIOSITY
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Dr Angelo Fraietta
A.Eng, A.Mus.A, BA(Hons), PhD.

Home Page

https://www.newcastleguitarlessons.com.au/
https://orcid.org/0000-0002-3171-8491

There are those who seek knowledge for the sake of knowledge - that is CURIOSITY
There are those who seek knowledge to be known by others - that is VANITY
There are those who seek knowledge in order to serve - that is LOVE
    Bernard of Clairvaux (1090 - 1153)

[Angelo Fraietta]

Yes, i did it at Nime.  I have a library for connecting between stellarium and vizier and sonifying it

On Thu, 29 Apr 2021 at 5:07 pm, Alessandro Fogar <sfo...@gmail.com> wrote:

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[Alessandro Fogar]

Angelo,

yes, I would love to use StellarCommand (with no internet) !

Can you guide me please ?

I've already read the paper: "Stellar Command: a planetarium software based cosmic performance interface".

All the best

AF

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[Alessandro Fogar]

Georg,

many thanks for your very interesting and deep reply.

All the best

AF

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[Angelo Fraietta]

Will you have access to the internet from the computer in preparation for performances? 

[Alessandro Fogar]

Angelo,

Yes, of course !

Many thanks

AF

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[Alessandro Fogar]

Angelo, 

I've read the Stellar command manual and I understood the basic behaviour.

Still cannot understand how I can obtain the celestial object passing over the meridian line...

Can you please explain ?

Have I perhaps to send multiple OSC messages like this ?

/Stellar/osc 1.0 186.6492 -63.0989

Many many thanks and excuse me...

All the best

AF

Il giorno ven 30 apr 2021 alle ore 07:07 Angelo Fraietta <ang...@smartcontroller.com.au> ha scritto:

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[Angelo Fraietta]

Greetings

First point, Stellar Command does not directly tell you the objects at the meridian from Stellarium, however, you can derive it with some cunning through VizieR - either live or with saved tables.

First, can I make the assumption that you will be displaying Stellarium with the meridian at the centre? If so, this makes it very easy. 

If my assumption is correct (that you are displaying meridian in the centre) Stellar Command will send you OSC messages for the RA/Dec for the centre position of the display as it changes as time progresses.  Stars in your VizieR table (if you are preloading) can be matched by filtering those with same RA (within a tolerance). 

If my assumption is wrong regarding display of Meridian (or rather, the meridian being at the centre of your display), please let me know. That simply becomes a mathematical equation for getting RA at the meridian given a date/time/geographical location.

I would love to hear your ideas.

Warmest regards

[Alessandro Fogar]

Hi,

yes, I know that Stellar Command does not directly tell me the objects at the meridian from Stellarium.

But I confirm that during the installation I'll be displaying Stellarium with the meridian at the centre.

I hoped to be able to show the stars intersecting the meridian zooming a little bit.

Please look at this example (here I changed the zoom factor, that can remain constant):

http://fogar.it/Stellarium.mp4

Many thanks for your precious help...

All the best

AF

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[Angelo Fraietta]

I had a look at your video. Are you running Stellarium in a browser?  I use the actual Stellarium app and connect through Remote Control

[Alessandro Fogar]

Angelo,

No, the regular app on Mac os.

Cheers

AF

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[Georg Zotti]

> That simply becomes a mathematical equation for getting RA at the meridian given a date/time/geographical location.

This is Sidereal Time and is available in the object info.

[Allan Royal]

Gostaria de opinar também sobre o stellarium ter fração de segundos , isso para astrometria seria um salto muito significativo !!!

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[Angelo Fraietta]

Yes, but we don't have any objects. So we need the RA from the display via remote control and then we query VizieR (or the pre-saved tables) for objects at that RA.  

[Angelo Fraietta]

It will be easy to get Stellarium to Meridian - simply send a set azimuth to 0 - which is north - through OSC.

If you want to do a setup, the way I would do a script and run it using the script command in OSC.

You can use the loadTables command if you have pr-saved tables.

[Alessandro Fogar]

Dear Georg,

I succeeded at last to build Stellarium and I'd like to do what you suggested, I'd need not only the stars but other interesting objects too (like 1000 or 2500 brightest stars, the planets, the satellites, the moon, the galaxies, the constellation lines, the ISS, etc.).

I am really in a hurry (first show is in 1 month, probably in Austria too, during the summer), I need your (or other's) precious help please...

I looked into SpecialZoneArray<Star>::draw() in ZoneArray.cpp but I need some guidance if possible. It seems that the stars there have fixed coordinates i.e. don't move.

And obviously I need the other objects too...

At the moment the idea is to build a special release of Stellarium with the modifications to send the data to Sc3 via OSC (I already know how to do the OSC part).

Many thanks in advance

Best regards

Alessandro Fogar

Il giorno gio 29 apr 2021 alle ore 10:15 Georg Zotti <georg...@univie.ac.at> ha scritto:

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[Georg Zotti]

OMG, first show in 1 month?

Yes, the stars in the catalog don't move as StelPainter does the rendering after projection. Still, inside the method you see:

if (withExtinction)

{ Vec3f altAz(vf); altAz.normalize();

core->j2000ToAltAzInPlaceNoRefraction(&altAz);

float extMagShift=0.0f; extinction.forward(altAz, &extMagShift);

extinctedMagIndex = s->getMag() + static_cast<int>(extMagShift/k);

if (extinctedMagIndex >= cutoffMagStep || extinctedMagIndex<0) // i.e., if extincted it is dimmer than cutoff or extinctedMagIndex is negative (missing star catalog), so remove

continue; 

}

This needs and shows how to convert to AltAz coordinates. (Use StelUtils::rectToSphe() to convert to angles [radians] if needed) If azimuth is close enough to 0 (in this internal routine, 0=south (?)), trigger your sound (modulate by altitude?)

Run this method (or a loop similar to this) in your plugin 1/second to not overstress the audio system. If you modify Stellarium in this area directly, I cannot say what happens. If in panic, maybe add a counter and emit the audio commands only every 15 or 100 frames.

For the planets, you should take a look into SolarSystem::draw(). Instead of drawing the planet, ask for its position, convert to AltAz, place a sound where you want it.

HTH, good luck!

Georg

[Alessandro Fogar]

Georg,

Many thanks !

What about galaxies, satellites and Constellation lines ?

All the best

AF

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[Georg Zotti]

Well, one after the other...

Look into the draw() methods of each object class. Each object can provide Vec3d StelObject::getAltAzPosApparent(const StelCore* core) const;

You must test if position is reasonably close to the meridian. There is no built-in "trigger" for moving over the meridian.

How do you sonify constellation lines? Find center of every line and handle this?

G.

[Alessandro Fogar]

Georg, 

Many thanks again !

About the constellation... No, I'd like to receive the position where the constellation line encounters the meridian and then I use that to sonify.

I'd also need the constellation name if possible...

Best

AF

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[Georg Zotti]

May even be easier: each line has two stars. Test if one star is east, the other west, and continue sound if true.

Look into ConstellationMgr::drawLines() and drawNames().

[Alessandro Fogar]

Dear Georg,

I am trying to apply some changes to Stellarium code with your precious suggestions...

Yes, now I am able to see that the stars in the catalog move...

There's only a thing I cannot understand, it's like if the stars come in big chunks of data and this render the triggering of the sound events not really continuous, 

And also when you zoom something (for example Antares) I obtain different behaviors.

This for sure arises from the fact that I ignore the inner workings of Stellarium...

I include the modified code and two examples of output showing the behaviour.

If you can, please let me know...

Many many thanks

Alessandro Fogar

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[Georg Zotti]

Hi!

Yes, the stars come in chunks, for efficiency. But I am sorry, this part of the code is not mine. I must reverse-engineer this as well and am too short in time these weeks to dive further into your project, sorry. 

[travis barbier]

Can someone write code that can connect my Celestron Astro fi to stellarium?

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[Georg Zotti]

You could, when you have identified objects you need to sonify (close enough to the meridian), collect the relevant data of such objects (e.g. type, magnitude, color?) into your own lists and then once per frame (or once per second ?) call a function to trigger these sounds. Maybe this gives more accurate timing. I don't know how much it disturbs the sounds when trigger points are not in sync by 1/60 s or so (within 1 frame).

sfo...@gmail.com schrieb am Dienstag, 8. Juni 2021 um 13:38:50 UTC+2:

[Alexandros Kosiaris]

Astro Fi seems to be an embedded version of the Celestron Skyportal
Wifi module. If that's true, then it might not be needed to write any
kind of code for this to work. Googling for Skyportal and ASCOM (if
you are using windows), or Skyportal and INDI (if you are using
linux/mac) does return a few results of people having tried to do
that, reportedly successfully. That being said, it looks like a old,
tedious and error prone path with no guarantee of success, and very
few docs. If you are the tinkering type and feel like going into some
pain to get it to work, you can try them out. Otherwise, my guess
would be you are a bit out of luck.

> To view this discussion on the web visit https://groups.google.com/d/msgid/stellarium/CAJUFNyfThFJO4Vza3ozwYM_ZZbxykyaDMh5DkFVbpGKEd0w29Q%40mail.gmail.com.

[travis barbier]

I have used the platform from the last time for so long and I also have been using sky safari when it was available and it connected to my telescope and it did very well but recently I switched from Samsung to Apple and the app was not free anymore so I cannot get sky safari so for the past few months I have been using this the last time platform and have seen literally it’s the worst the reason is because it is so limited On how many stars at Kinsey recently I tried to do a list for stargazing challenge and literally this last year and had none of the items on the list which was 50 items including mostly of which were NGC objects.

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[Georg Zotti]

Please stop hijacking this thread. This is about an artist's project, not about support for some Celestron telescope. I will delete further unrelated posts.

[travis barbier]

I apologize for what I said I am only requesting that someone can make a program that can allow Celestron Astro fi telescopes connect with stellarium because it would be a huge help for me.

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[Alexandros Kosiaris]

Oops, sorry, my mistake.

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[Alessandro Fogar]

Georg,

let me say at first, many many thanks for your support...

I'm slowly understanding where I have to intercept the data and trigger the OSC messages.

I hope to finish soon.

Many thanks

Best regards

AF

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