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APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 5:06 am
by 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.
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 6:15 am
by Ann
The Tarantula Nebula with the remnant of SN 1987A.
Photo: Ignacio Diaz Bobillo.
So where is the supernova remnant in today's APOD? Can you spot it?
Ann
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 12:31 pm
by orin stepanek
Ann wrote: ↑Fri Nov 13, 2020 6:15 am
Tarantula_HOO_final_2_1024[1].jpg
The Tarantula Nebula with the remnant of SN 1987A.
Photo: Ignacio Diaz Bobillo.
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!
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 12:34 pm
by Tszabeau
It looks angry.
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 3:15 pm
by 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
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 3:32 pm
by 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?"
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 4:02 pm
by 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.
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 5:21 pm
by 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
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 5:23 pm
by neufer
The statement that this
"view spans about 2 degrees or 4 full moons" seems rather fishy to me.
![Fishy :fish:](./images/smilies/animal0028.gif)
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 5:24 pm
by ignacio_db
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 5:40 pm
by ignacio_db
neufer wrote: ↑Fri Nov 13, 2020 5:23 pm
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
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 6:32 pm
by Ann
ignacio_db wrote: ↑Fri Nov 13, 2020 5:21 pm
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
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
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 7:38 pm
by johnnydeep
ignacio_db wrote: ↑Fri Nov 13, 2020 5:40 pm
neufer wrote: ↑Fri Nov 13, 2020 5:23 pm
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?
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 7:40 pm
by johnnydeep
rkennaway wrote: ↑Fri Nov 13, 2020 3:32 pm
"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
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 7:58 pm
by ignacio_db
johnnydeep wrote: ↑Fri Nov 13, 2020 7:38 pm
ignacio_db wrote: ↑Fri Nov 13, 2020 5:40 pm
neufer wrote: ↑Fri Nov 13, 2020 5:23 pm
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
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 10:31 pm
by 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?)
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Fri Nov 13, 2020 11:32 pm
by Chris Peterson
Tarantulas are very nice wrote: ↑Fri Nov 13, 2020 10:31 pm
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.
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Sat Nov 14, 2020 4:51 am
by Ann
Chris Peterson wrote: ↑Fri Nov 13, 2020 11:32 pm
Tarantulas are very nice wrote: ↑Fri Nov 13, 2020 10:31 pm
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
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Sat Nov 14, 2020 1:13 pm
by Chris Peterson
Ann wrote: ↑Sat Nov 14, 2020 4:51 am
Chris Peterson wrote: ↑Fri Nov 13, 2020 11:32 pm
Tarantulas are very nice wrote: ↑Fri Nov 13, 2020 10:31 pm
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.
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Sat Nov 14, 2020 1:55 pm
by Ann
Chris Peterson wrote: ↑Sat Nov 14, 2020 1:13 pm
Ann wrote: ↑Sat Nov 14, 2020 4:51 am
Chris Peterson wrote: ↑Fri Nov 13, 2020 11:32 pm
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
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Sat Nov 14, 2020 2:13 pm
by Chris Peterson
Ann wrote: ↑Sat Nov 14, 2020 1:55 pm
Chris Peterson wrote: ↑Sat Nov 14, 2020 1:13 pm
Ann wrote: ↑Sat Nov 14, 2020 4:51 am
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.
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Sat Nov 14, 2020 7:30 pm
by johnnydeep
ignacio_db wrote: ↑Fri Nov 13, 2020 7:58 pm
johnnydeep wrote: ↑Fri Nov 13, 2020 7:38 pm
ignacio_db wrote: ↑Fri Nov 13, 2020 5:40 pm
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.
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Sat Nov 14, 2020 7:51 pm
by Chris Peterson
johnnydeep wrote: ↑Sat Nov 14, 2020 7:30 pm
ignacio_db wrote: ↑Fri Nov 13, 2020 7:58 pm
johnnydeep wrote: ↑Fri Nov 13, 2020 7:38 pm
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.
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Sat Nov 14, 2020 10:21 pm
by johnnydeep
Chris Peterson wrote: ↑Sat Nov 14, 2020 7:51 pm
johnnydeep wrote: ↑Sat Nov 14, 2020 7:30 pm
ignacio_db wrote: ↑Fri Nov 13, 2020 7:58 pm
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!
Re: APOD: The Tarantula Zone (2020 Nov 13)
Posted: Sun Nov 15, 2020 4:54 am
by alter-ego
johnnydeep wrote: ↑Sat Nov 14, 2020 10:21 pm
Chris Peterson wrote: ↑Sat Nov 14, 2020 7:51 pm
johnnydeep wrote: ↑Sat Nov 14, 2020 7:30 pm
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.