APOD: The Tarantula Zone (2020 Nov 13)

[APOD Robot]

The Tarantula Zone

Explanation: The Tarantula Nebula, also known as 30 Doradus, is more than a thousand light-years in diameter, a giant star forming region within nearby satellite galaxy the Large Magellanic Cloud. About 180 thousand light-years away, it's the largest, most violent star forming region known in the whole Local Group of galaxies. The cosmic arachnid sprawls across the top of this spectacular view, composed with narrowband filter data centered on emission from ionized hydrogen and oxygen atoms. Within the Tarantula (NGC 2070), intense radiation, stellar winds and supernova shocks from the central young cluster of massive stars, cataloged as R136, energize the nebular glow and shape the spidery filaments. Around the Tarantula are other star forming regions with young star clusters, filaments, and blown-out bubble-shaped clouds. In fact, the frame includes the site of the closest supernova in modern times, SN 1987A, right of center. The rich field of view spans about 2 degrees or 4 full moons, in the southern constellation Dorado. But were the Tarantula Nebula closer, say 1,500 light-years distant like the local star forming Orion Nebula, it would take up half the sky.

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[Ann]

The Tarantula Nebula with the remnant of SN 1987A.
Photo: Ignacio Diaz Bobillo.

Supernova 1987A (center) at the time of explosion. Photo: ESO - https://www.eso.org/public/images/eso0708a/

---

So where is the supernova remnant in today's APOD? Can you spot it?

Ann

[orin stepanek]

Tarantula_HOO_final_2_1024[1].jpg

The Tarantula Nebula with the remnant of SN 1987A.
Photo: Ignacio Diaz Bobillo.

Supernova 1987A (center) at the time of explosion. Photo: ESO - https://www.eso.org/public/images/eso0708a/

---

So where is the supernova remnant in today's APOD? Can you spot it?

Ann

Ann I'm not good at finding Nova's! The Tarantula doeesn't look like a place I'd like to visit!

[Tszabeau]

It looks angry.

[VictorBorun]

seems 1987A (bright star to the right and low besides the Tarantula) in 2020 looks dark
https://www.facebook.com/AstronomyPictu ... _tn__=R]-R

[rkennaway]

"Formless protoplasm able to mock and reflect all forms and organs and processes — viscous agglutinations of bubbling cells — rubbery fifteen-foot spheroids infinitely plastic and ductile — slaves of suggestion, builders of cities — more and more sullen, more and more intelligent, more and more amphibious, more and more imitative! Great God! What madness made even those blasphemous Old Ones willing to use and carve such things?"

[NCTom]

My guess as to location of 1987A is about 4 o'clock from the center of the Tarantula in the middle of a small dark cavity containing two stars one of which is the supernova remnant. When the probe gets there in a million years, we'll know for sure.

[ignacio_db]

I registered both images against each other, and cropped the SN area with the same geometry. Could it be the red star at the center, sided by two white stars?

Ignacio

[neufer]

The Tarantula Zone

Explanation: The rich field of view spans about 2 degrees or 4 full moons, in the southern constellation Dorado.

The statement that this "view spans about 2 degrees or 4 full moons" seems rather fishy to me.

[ignacio_db]

Looking further, I think it is: https://www.nasa.gov/sites/default/file ... 3x2000.png

Ignacio

[ignacio_db]

The Tarantula Zone

Explanation: The rich field of view spans about 2 degrees or 4 full moons, in the southern constellation Dorado.

The statement that this "view spans about 2 degrees or 4 full moons" seems rather fishy to me.

The precise FOV is 1d 3' 47.8" x 1d 18' 46.0".

Ignacio

[Ann]

I registered both images against each other, and cropped the SN area with the same geometry. Could it be the red star at the center, sided by two white stars?

Ignacio

1987A supernova remnant. Composite of two public domain NASA images taken from the Hubble Space Telescope. See more at https://sv.wikipedia.org/wiki/SN_1987A#/media/Fil:Supernova-1987a.jpg.

---

Yes indeed, you have found it. Compare your image with the one by the Hubble Space Telescope here. Note the red Hα ring and the two white stars flanking it.

Ann

[johnnydeep]

The Tarantula Zone

Explanation: The rich field of view spans about 2 degrees or 4 full moons, in the southern constellation Dorado.

The statement that this "view spans about 2 degrees or 4 full moons" seems rather fishy to me.

The precise FOV is 1d 3' 47.8" x 1d 18' 46.0".

Ignacio

So, this is roughly 1 degree x 1 degree, and not 2 degrees wide per the text? How did you determine the exact field of view?

[johnnydeep]

"Formless protoplasm able to mock and reflect all forms and organs and processes — viscous agglutinations of bubbling cells — rubbery fifteen-foot spheroids infinitely plastic and ductile — slaves of suggestion, builders of cities — more and more sullen, more and more intelligent, more and more amphibious, more and more imitative! Great God! What madness made even those blasphemous Old Ones willing to use and carve such things?"

If this site had "recs" I'd give you one for the Lovecraft reference! "At The Mountains Of Madness" indeed: http://www.lovecraft-stories.com/pdf/at ... adness.pdf

[ignacio_db]

The statement that this "view spans about 2 degrees or 4 full moons" seems rather fishy to me.

The precise FOV is 1d 3' 47.8" x 1d 18' 46.0".

Ignacio

So, this is roughly 1 degree x 1 degree, and not 2 degrees wide per the text? How did you determine the exact field of view?

By plate-solving the image.

Ignacio

[Tarantulas are very nice]

were the Tarantula Nebula closer, say 1,500 light-years distant like the local star forming Orion Nebula, it would take up half the sky

Imagine getting out of the cabin at night and seeing that across half the sky. Our view of nature would perhaps be rather less arrogant, and astronomy would be taken seriously indeed.

(We'd have H-alpha eyes, the right atmosphere, and a high tolerance for being blasted by supernovae, OK?)

[Chris Peterson]

were the Tarantula Nebula closer, say 1,500 light-years distant like the local star forming Orion Nebula, it would take up half the sky

Imagine getting out of the cabin at night and seeing that across half the sky. Our view of nature would perhaps be rather less arrogant, and astronomy would be taken seriously indeed.

(We'd have H-alpha eyes, the right atmosphere, and a high tolerance for being blasted by supernovae, OK?)

The problem is that even with 100% efficient eyes, you'd still need to stare at one spot in the sky for many minutes, and somehow integrate the photons your eyes were collecting, to see anything remotely like this.

In reality, if we were close enough to this to see it covering half the sky, it would look like a barely discernible gray haze, dimmer than the Milky Way.

[Ann]

were the Tarantula Nebula closer, say 1,500 light-years distant like the local star forming Orion Nebula, it would take up half the sky

Imagine getting out of the cabin at night and seeing that across half the sky. Our view of nature would perhaps be rather less arrogant, and astronomy would be taken seriously indeed.

(We'd have H-alpha eyes, the right atmosphere, and a high tolerance for being blasted by supernovae, OK?)

The problem is that even with 100% efficient eyes, you'd still need to stare at one spot in the sky for many minutes, and somehow integrate the photons your eyes were collecting, to see anything remotely like this.

In reality, if we were close enough to this to see it covering half the sky, it would look like a barely discernible gray haze, dimmer than the Milky Way.

Okay, but this part of the Tarantula Nebula would surely be ablaze at a distance of only 1500 light-years, right?

Ann

[Chris Peterson]

Imagine getting out of the cabin at night and seeing that across half the sky. Our view of nature would perhaps be rather less arrogant, and astronomy would be taken seriously indeed.

(We'd have H-alpha eyes, the right atmosphere, and a high tolerance for being blasted by supernovae, OK?)

The problem is that even with 100% efficient eyes, you'd still need to stare at one spot in the sky for many minutes, and somehow integrate the photons your eyes were collecting, to see anything remotely like this.

In reality, if we were close enough to this to see it covering half the sky, it would look like a barely discernible gray haze, dimmer than the Milky Way.

Okay, but this part of the Tarantula Nebula would surely be ablaze at a distance of only 1500 light-years, right?

You'd see a cluster of bright stars. The nebulosity wouldn't be anything other than a faint glow. If fact, the bright stars might make it harder to see than in some other parts.

[Ann]

The problem is that even with 100% efficient eyes, you'd still need to stare at one spot in the sky for many minutes, and somehow integrate the photons your eyes were collecting, to see anything remotely like this.

In reality, if we were close enough to this to see it covering half the sky, it would look like a barely discernible gray haze, dimmer than the Milky Way.

Okay, but this part of the Tarantula Nebula would surely be ablaze at a distance of only 1500 light-years, right?

You'd see a cluster of bright stars. The nebulosity wouldn't be anything other than a faint glow. If fact, the bright stars might make it harder to see than in some other parts.

I get it, Chris, but you know me... I often prefer the bright (blue) stars over the nebulosity anyway.

Surely R136 would look like a mighty impressive cluster from a distance of 1,500 light-years?

Ann

[Chris Peterson]

Okay, but this part of the Tarantula Nebula would surely be ablaze at a distance of only 1500 light-years, right?

You'd see a cluster of bright stars. The nebulosity wouldn't be anything other than a faint glow. If fact, the bright stars might make it harder to see than in some other parts.

I get it, Chris, but you know me... I often prefer the bright (blue) stars over the nebulosity anyway.

Surely R136 would look like a mighty impressive cluster from a distance of 1,500 light-years?

Ann

I'm not sure it would- it's pretty tiny. A lot of bright stars that are very close together might or might not look all that impressive to the naked eye. From 1500 ly, it would be about the same size as the Pleiades. Its dozen or so most luminous members would be about 1000 times brighter than the stars that make up the Pleiades... which sounds like a lot, but given the logarithmic nature of our vision, really isn't (7-8 magnitudes). I guess it would look like a fairly bright globular cluster- an obvious fuzzy spot in which those with good vision would see a few distinct stars, not unlike the Pleiades, but certainly brighter.

[johnnydeep]

The precise FOV is 1d 3' 47.8" x 1d 18' 46.0".

Ignacio

So, this is roughly 1 degree x 1 degree, and not 2 degrees wide per the text? How did you determine the exact field of view?

By plate-solving the image.

Ignacio

Ok. I had to look up "plate-solving". Did you do this with software or manually? And, again, assuming your FOV is correct, the APOD is wrong to say it is 2 degrees wide, right?

From https://www.astrophotography.app/usersg ... olving.htm

Plate-solving is a image analysis that detects the stars and then tries to identify them using catalogs of know stars. If the analysis is successful it is possible to calculate the Right Accession (RA) and Declination (Dec) of the image center which tells where exactly is pointing the telescope, image orientation, resolution and etc. Plate-solving is the engine of many scientific studies for example comet, asteroid hunting and orbit analysis.

Nowadays we are lucky to have access to many advanced techniques and devices that in the past were available only for the biggest professional observatories. Plate-solving is one these techniques that makes imaging much productive, accurate and pleasant. There are two types of solving - Near and Blind. The first one needs to know approximately where "you are" and solving will tell you exactly where "you are", it is very fast because you already know context . For the second one you don't need know where "you are" and solving will find the position without knowing the starting position, it is slower because there is need to match star patterns from all over the sky.

[Chris Peterson]

So, this is roughly 1 degree x 1 degree, and not 2 degrees wide per the text? How did you determine the exact field of view?

By plate-solving the image.

Ignacio

Ok. I had to look up "plate-solving". Did you do this with software or manually? And, again, assuming your FOV is correct, the APOD is wrong to say it is 2 degrees wide, right?

It can be done inside some image processing programs (this image was processed with PixInsight, which has a plate solving tool). It can also be done by uploading an image to Astrometry.net, which can solve almost anything. This image has almost all the stars processed out, by virtue of so much signal coming from a very narrow H-alpha and OIII channels. But there were probably enough stars in the unprocessed frames to get a solution. It's also easy enough to just solve a clean star field, which will give you the pixel scale for a given imaging train, and just use that value, multiplied by the number of pixels on an axis.

[johnnydeep]

By plate-solving the image.

Ignacio

Ok. I had to look up "plate-solving". Did you do this with software or manually? And, again, assuming your FOV is correct, the APOD is wrong to say it is 2 degrees wide, right?

It can be done inside some image processing programs (this image was processed with PixInsight, which has a plate solving tool). It can also be done by uploading an image to Astrometry.net, which can solve almost anything. This image has almost all the stars processed out, by virtue of so much signal coming from a very narrow H-alpha and OIII channels. But there were probably enough stars in the unprocessed frames to get a solution. It's also easy enough to just solve a clean star field, which will give you the pixel scale for a given imaging train, and just use that value, multiplied by the number of pixels on an axis.

Neat!

[alter-ego]

Ok. I had to look up "plate-solving". Did you do this with software or manually? And, again, assuming your FOV is correct, the APOD is wrong to say it is 2 degrees wide, right?

It can be done inside some image processing programs (this image was processed with PixInsight, which has a plate solving tool). It can also be done by uploading an image to Astrometry.net, which can solve almost anything. This image has almost all the stars processed out, by virtue of so much signal coming from a very narrow H-alpha and OIII channels. But there were probably enough stars in the unprocessed frames to get a solution. It's also easy enough to just solve a clean star field, which will give you the pixel scale for a given imaging train, and just use that value, multiplied by the number of pixels on an axis.

Neat!

There's more than enough visible detail to determine the field by eye when overlapping images. Having an FOV [X,Y] error of [10",6"], the visually dialed-in DSS2 image with the APOD image is shown in the hover-image below. I normally don't attempt that level of precision, but I was curious how well I could measure the FOV given Ignacio's stated dimensions.
  

Click to view full size image 1 or image 2