Astronomy News

[FrumiousBandersnatch]

Here is a comparison between the mathematical process which remaps the pixel values in the image and using the camera software.

Professional astronomers use FITS Liberator for processing images which I find does not enhance the faint detail as well as the mathematical process.

Wow, that looks really good! As for artefacts, I'll leave that for the experts to decide

 

[sjastro]

Wow, that looks really good! As for artefacts, I'll leave that for the experts to decide

Ultimately the experts were satisfied.
I sent an image to ESO of the Carina Dwarf Galaxy one of the Milky Way satellite galaxies.
This galaxy is so notoriously faint it's surface brightness is fainter than the natural skyglow in the Earth's upper atmosphere.
It is theoretically possible to image as the combined surface brightness of the galaxy and the Earth's skyglow is fractionally brighter than the skyglow alone.

This is a 50 hr exposure with a small 28 cm telescope and a CCD which sophisticated by amateur standards is primitive to the state of the art CCDs used by professional astronomers.
The galaxy is invisible on the right when processed conventionally.
ESO were dubious to put it mildly as they thought it was impossible to image the Carina Dwarf using amateur equipment.

They did however provide me with their unprocessed data of the Carina Dwarf taken with the 4 metre and 2.2 metre telescopes from Chile.
ESO stipulated the conditions for processing.
(1) No sharpening
(2) No contrast enhancement.
(3) No colour saturation.
(4) No photo-shopping etc.

The data was processed using the maths process and Fits Liberator which is the standard processing package used by the professionals.
I decided to process the data as a monochrome image.

The left hand image is the maths processed image the right hand processed with FITS liberator.
Whereas my amateur image shows the Carina dwarf as a "cloud" the larger professional scopes resolves the cloud into individual stars in a smaller field of view.

While they were critical in how I combined their individual images they gave the left hand image the thumbs up as being the real thing not composed of artefacts.
Being non linear processing the left hand image cannot be used be used for astronomical photometry.

Dear Steven,

Impressive data processing! It is very hard to evaluate it in details on the re-scaled JPG (which loses lots of information wrt the FITS), but here are some comments:

- The noise texture in the background, and the large-scale flatness of the background suggests you have used a sky-subtraction algorithm (which is OK) using a sampling window that is too small (probably 100pix, while you could push it to ~500 or 1000)?

- the overall depth of the image is really good!

- combining the data over a huge wavelength range UBVI can be counter productive, even if your only goal is to go deep. For instance, the individual U images tend to be much shallower (because the camera is less sensitive in U, and bc the stars are fainter in U), so if you average them with the others without a different weight, you actually increase the noise more than the signal. You could consider to use the following weight for each image:
w = F/t
with t = exposure time (i.e. normalize by exposure time) and
F(U) = 0.2; F(B) = 0.4; F(V) = 1; F(R) = 1.5; F(I) = 0.8
An other way would be to pick a star that is not saturated in any of the images and that has neutral colours in our image, and normalize the frames by the (sky-subtracted) flux of that star.
If you have the time/the patience, you could give it a try, and I would not be surprised if the end result is a little deeper.

Note also that for the astronomers, combining all the filters together is usually not useful. It can help to create a catalogue of positions of the starts, and then go back and measure the flux in the single-filter recombinations U, B, V, R, I.

- the stretch function you apply is very good for displaying the image - but for us the only useful one is the original linear pixels. The stretch functions are really just for display. Anything that screws up the linearity of the data is a problem (and actually, we sometimes have problems with the raw data being not perfectly linear).

Cheers
oli

 

[FrumiousBandersnatch]

Ultimately the experts were satisfied.
I sent an image to ESO of the Carina Dwarf Galaxy one of the Milky Way satellite galaxies.
This galaxy is so notoriously faint it's surface brightness is fainter than the natural skyglow in the Earth's upper atmosphere.
It is theoretically possible to image as the combined surface brightness of the galaxy and the Earth's skyglow is fractionally brighter than the skyglow alone.

This is a 50 hr exposure with a small 28 cm telescope and a CCD which sophisticated by amateur standards is primitive to the state of the art CCDs used by professional astronomers.
The galaxy is invisible on the right when processed conventionally.
ESO were dubious to put it mildly as they thought it was impossible to image the Carina Dwarf using amateur equipment.

They did however provide me with their unprocessed data of the Carina Dwarf taken with the 4 metre and 2.2 metre telescopes from Chile.
ESO stipulated the conditions for processing.
(1) No sharpening
(2) No contrast enhancement.
(3) No colour saturation.
(4) No photo-shopping etc.

The data was processed using the maths process and Fits Liberator which is the standard processing package used by the professionals.
I decided to process the data as a monochrome image.

The left hand image is the maths processed image the right hand processed with FITS liberator.
Whereas my amateur image shows the Carina dwarf as a "cloud" the larger professional scopes resolves the cloud into individual stars in a smaller field of view.

While they were critical in how I combined their individual images they gave the left hand image the thumbs up as being the real thing not composed of artefacts.
Being non linear processing the left hand image cannot be used be used for astronomical photometry.

Very nice! I suppose the type and amount of data manipulation will depend on the purpose of the processing.

 

[Michael]

Here is an image I took of the Antares region (red star on the right) taken with very simple equipment a 300mm telephoto lens and a Pentax k-r camera, no telescope, no fancy ultra cooled CCD equipment.
I have been able to develop a mathematical process where very faint detail can be brought out without excessively increasing the noise.

Are you using any sort of equipment to "track" the object over time? The images you're getting are simply amazing.

 

[SelfSim]

Are you using any sort of equipment to "track" the object over time? The images you're getting are simply amazing.

More importantly than the sense of awe we get, (and rightly so), is the successfully demonstrated application of math in physics, which generated that awe.
Ie: its not just a simple case of relying on high precision equipment .. as is evidenced by the lack of detail in the raw (unprocessed) images.

 

[sjastro]

Very nice! I suppose the type and amount of data manipulation will depend on the purpose of the processing.

One of the main aspects of data manipulation is to improve the aesthetic value of the image.
The Hubble images presented by NASA for public consumption have a whizzbang factor, which has more of a PR effect than scientific value; the data studied by astronomers is far more mundane.
Manipulating the data so as to go deeper in an image does have scientific value and can be useful for supernova surveys and hunting for fainter more distant galaxies as examples.
Once a discovery is made linear processing is required in order for the science to be done.

 

[sjastro]

Are you using any sort of equipment to "track" the object over time? The images you're getting are simply amazing.

The CCD I use has an imaging chip and a tracking chip.
The tracking chip locks in on a guide star and takes images of the star in short intervals.
If the star moves on the chip between intervals the CCD sends a signal to the equatorial mount which makes an adjustment.

Life is far easier than it was 20+ years ago in the age of using film and tracking manually.
Being stuck on top of a mountain in below freezing temperatures doing 3hr+ exposures while glued to the guiding eyepiece was the height of masochism.

 

[Michael]

The CCD I use has an imaging chip and a tracking chip.
The tracking chip locks in on a guide star and takes images of the star in short intervals.
If the star moves on the chip between intervals the CCD sends a signal to the equatorial mount which makes an adjustment.

Life is far easier than it was 20+ years ago in the age of using film and tracking manually.
Being stuck on top of a mountain in below freezing temperatures doing 3hr+ exposures while glued to the guiding eyepiece was the height of masochism.

Thanks for that information. Indeed, technology has improved life significantly during my (our) lifetime(s).

 

[Michael]

More importantly than the sense of awe we get, (and rightly so), is the successfully demonstrated application of math in physics, which generated that awe.
Ie: its not just a simple case of relying on high precision equipment .. as is evidenced by the lack of detail in the raw (unprocessed) images.

True. It's the *way* that math is applied to physics that makes all the difference. Math as it was used by Copernicus was useful and helpful in terms of understanding *how* our universe physically works, whereas the math as applied by Ptolemy, not so much.

 

[Halbhh]

Most planets in recent years thought to be in the 'habitable zone' or optimistically dubbed 'Earth like' aren't likely to be (since red dwarfs are the most common type of star). The actual magnetic field of the star itself can help strip the planetary atmosphere--

"These "Goldilocks" planets may enjoy temperatures and atmospheric pressures that allow life-giving water to exist, but likely orbit too close to their stars to escape the effects of the star's strong magnetic fields and the associated radiation.

"Depending on where it is within the extended magnetic field of the star, it is estimated that some of these habitable zone exoplanets could lose their atmospheres in as little as 100 million years," Alexander said. "That is a really short time in astronomical terms. The planet may have the right temperature and pressure conditions for habitability, and some simple lifeforms might form, but that's as far as they're going to go. The atmosphere would be stripped and the radiation on the surface would be pretty intense.

"When you don't have an atmosphere, you now have all the ultraviolet and X-ray emission from the star on top of the particle emission," he said. "We want to understand this interaction better and be able to compare it with observations in the future. And the ability to direct and define the nature of these future observations will be really helpful."
https://phys.org/news/2019-10-goldilocks-exoplanets-well-behaved-star.html

One of the main aspects of data manipulation is to improve the aesthetic value of the image.
The Hubble images presented by NASA for public consumption have a whizzbang factor, which has more of a PR effect than scientific value; the data studied by astronomers is far more mundane.
Manipulating the data so as to go deeper in an image does have scientific value and can be useful for supernova surveys and hunting for fainter more distant galaxies as examples.
Once a discovery is made linear processing is required in order for the science to be done.

@Astrophile .
@Ophiolite .
@Michael

Very nice! I suppose the type and amount of data manipulation will depend on the purpose of the processing.

 

[sjastro]

Here is an image I took of the Eta Carina Nebula.

Full resolution of image at;
EtaC_Ha_OIII

Of interest to the doomsday fans is the bright star near the centre Eta Carinae.
Eta Carinae is highly unstable and is expected to go supernova (if not already).
Type II supernovae that explode outside a 250 light year radius from the Earth are considered nonthreatening to life on Earth.
Eta Carinae is around 7500 light years distant and so should be considered safe except for the possibility of the explosion resulting in a GRB (Gamma Ray Burst).
Since Eta Carinae is rotating very rapidly ejected material would travel very near the speed of light. The effects of special relativity result in a phenomena known as relativistic beaming where a highly focused beam of gamma radiation is formed.
If the beam is pointed at the Earth mass extinction could result according to the doomsday followers.

What do astrophysicists claim; highly unlikely.
Fact or Fiction?: The Explosive Death of Eta Carinae Will Cause a Mass Extinction

 

[sjastro]

Strontium discovered in neutron star merger.

The r-process or rapid neutron capture process is believed to be responsible for the production of at least half the nuclei heavier than iron (Fe).
Until now the environment in which the r-process occurs was uncertain.
First Identification of a Heavy Element Born from Neutron Star Collision - Newly created strontium, an element used in fireworks, detected in space for the first time following observations with ESO telescope

 

[Halbhh]

Strontium discovered in neutron star merger.

The r-process or rapid neutron capture process is believed to be responsible for the production of at least half the nuclei heavier than iron (Fe).
Until now the environment in which the r-process occurs was uncertain.
First Identification of a Heavy Element Born from Neutron Star Collision - Newly created strontium, an element used in fireworks, detected in space for the first time following observations with ESO telescope

An impressive feat to get the signature pinned down for strontium.

You should find this 2017 report very interesting also, with detail about confirming predictions of light after mergers from heavy elements--
https://phys.org/news/2017-10-astronomers-cosmic-gold-precious-metals.html

This article was fun also about how much gold:
The researchers found a vast amount of heavy elements in the solar system likely originated from a single neutron-star collision that occurred about 80 million years before the birth of the solar system. Based on the amount of material from this merger that managed to make it here, they suggested this merger happened about 1,000 light-years from the cloud of gas and dust that eventually formed the solar system.

Enough Gold and Uranium to equal the mass of all Earth's oceans.
Ancient Neutron-Star Crash Made Enough Gold and Uranium to Fill Earth's Oceans

 

[Halbhh]

Compelling interesting news:

A relatively nearby very large Red Giant star is dimming a lot(!)

https://phys.org/news/2019-12-betelgeuse-tempestuous-star.html

 

[Willis Gravning]

Compelling interesting news:

A relatively nearby very large Red Giant star is dimming a lot(!)

https://phys.org/news/2019-12-betelgeuse-tempestuous-star.html

Exciting news. Thanks for sharing

 

[dad]

Astronomy and Astrophysics News, photos, articles.

It could be fun to have a post/thread for the many believers (and seekers too) that like to see interesting Astronomy and Astrophysics and Cosmology News and articles.

Meaning stuff that is interesting news from observations, and photos/images from those.
New ideas/hypothesis from science articles trying to understand more about how stars work.
And galaxies
And collapsars (Neutron Stars and Black Holes, white dwarfs, etc.)
And the Universe large structure and change over time.

"Astronomers have observed reservoirs of cool gas around some of the earliest galaxies in the universe. These gas halos are the perfect food for supermassive black holes at the center of these galaxies, which are now seen as they were over 12.5 billion years ago. This food storage might explain how these cosmic monsters grew so fast during a period in the universe's history known as the Cosmic Dawn."

ESO observations reveal black holes' breakfast at the cosmic dawn

It seems science news these days is getting indistinguishable from guesses. Kind of like guessing what the Jolly Green Giant ate on his first breakfast.

 

[Halbhh]

"Astronomers have observed reservoirs of cool gas around some of the earliest galaxies in the universe. These gas halos are the perfect food for supermassive black holes at the center of these galaxies, which are now seen as they were over 12.5 billion years ago. This food storage might explain how these cosmic monsters grew so fast during a period in the universe's history known as the Cosmic Dawn."

ESO observations reveal black holes' breakfast at the cosmic dawn

It seems science news these days is getting indistinguishable from guesses. Kind of like guessing what the Jolly Green Giant ate on his first breakfast.

In astrophysics, cosmology, vanguard physics, the normal process is just like grouping in big dark room with a tiny light that barely allows us to see a bit nearby at times. That's normal.

 

[dad]

In astrophysics, cosmology, vanguard physics, the normal process is just like grouping in big dark room with a tiny light that barely allows us to see a bit nearby at times. That's normal.

OK, happy groping in the dark I guess.

 

[Ophiolite]

It seems science news these days is getting indistinguishable from guesses. Kind of like guessing what the Jolly Green Giant ate on his first breakfast.

Indeed. It's just as well that science news and science are not the same thing. Perhaps if you appreciated that and let it inform your thinking you would be less confused on scientific matters.

 

[dad]

Indeed. It's just as well that science news and science are not the same thing. Perhaps if you appreciated that and let it inform your thinking you would be less confused on scientific matters.

If three dozen Catholic priests and a dozen nuns were running around with machine guns holding up banks and corner stores, and shooting children under 6 years old, people would wonder about Catholicism. When dozens of scientists make statements and conduct experiments people associate that with science. Looking at the article cited, it uses scientific premises. How big the universe is, and how stars form. and what they eat, and the BB starting point etc. You can't disassociate this from science.

Science magazines and sites generally link some study or source as well.