The drawing depicts observations from the time period January 7 to 24, 1610.
The above is the sequence of photographs taken by JunoCam aboard the Juno
spacecraft, in June 2016, of Jupiter and the motion of the four Galilean
moons, as the spacecraft approached the planet.
Pareidolia is a psychological phenomenon in which the mind responds to a stimulus, usually an image or a sound, by perceiving a familiar pattern where none exists.
These are merely some images of stars and galaxies taken by the Hubble Space Telescope. But what do you see ?
You will notice that the trajectories taken by the sun and the planets are similar in the night sky.
This gives you a visual validation of the fact that the orbital plane of all the planets and the sun are similar. Just a little something that you may or may not have realized about the cosmos.
Go ahead, give it a shot and have fun!
* The ecliptic plane is the name given to the mean plane in the sky that the Sun follows over the course of a year;
But if you are an astronomer trying to study the cosmos from the earth, this turbulence of air and twinkling of stars is a nightmare.
The last thing that you want the light that painstakingly took millions of years to get to the earth is be wiggled away from your telescope through refraction and turbulence.
Adaptive Optics
Have you ever seen time lapses like these of the Keck observatory with laser beams coming out of it ?
Those lasers serve a purpose: to account for the atmosphere disturbances in the night sky in real time and correct the images that they observe dynamically.
This is known as Adaptive optics. This video by the RoyalObs explains the essence of Adaptive optics really well. Do watch it
With and Without Adaptive Optics
Prof. Andrea Ghez and her research team at UCLA whose research on what is at the center of our galaxy that was featured in our previous post has contributed a lot in using Adaptive optics for astronomical observations.
And using this technique, the following is the difference between capturing an image with and without adaptive optics.
And it is with the aid of adaptive optics that the group was able to track the trajectories of the galaxies surrounding the proposed center of our galaxy to conclude that there is most likely a Super Massive Black Hole at the center of it.
Trajectories of stars surrounding the proposed center of our galaxy.
So, the next time you go out to gaze at the cosmos, just remember that whatever you are seeing in the night sky right now is through the looking glass of our beloved atmosphere.
And astronomers put in immense effort to nullify the dynamic atmospheric effects that it loves to entertain us with.
Have a great day!
All images/animations featured in this post were created by Prof. Andrea Ghez and her
research team at UCLA and are from data sets obtained with the W. M.
Keck Telescopes
What is the Stratospheric
Observatory for Infrared Astronomy, or SOFIA, up to?
SOFIA, the
Stratospheric Observatory for Infrared Astronomy, as our flying telescope is called, is a Boeing 747SP aircraft
that carries a 2.5-meter telescope to altitudes as high as 45,000 feet.
Researchers use SOFIA to study the solar system and beyond using infrared
light. This type of light does not reach the ground, but does reach the
altitudes where SOFIA flies.
Recently, we used SOFIA to study water on Venus, hoping to
learn more about how
that planet lost its oceans. Our researchers used a powerful instrument on
SOFIA, called a spectrograph,
to detect water in its normal form and “heavy water,” which has an extra
neutron. The heavy water takes longer to evaporate and builds up over time. By
measuring how much heavy water is on Venus’ surface now, our team will be able
to estimate how much water Venus had when the planet formed.
We are also using SOFIA to create a detailed map of the Whirlpool
Galaxy by making multiple observations of the galaxy. This map will help us
understand how stars form from clouds in that galaxy. In particular, it will
help us to know if the spiral arms in the galaxy trigger clouds to collapse
into stars, or if the arms just show up where stars have already formed.
We can also use SOFIA to study methane on Mars. The Curiosity rover
has detected methane
on the surface of Mars. But the total amount of methane on Mars is unknown and
evidence so far indicates that its levels change significantly over time and
location. We are using SOFIA to search for evidence of this gas by mapping the Red
Planet with an instrument specially tuned to sniff out methane.
Next our team will use SOFIA to study Jupiter’s icy moon Europa, searching for evidence of possible water plumes detected by the Hubble Space Telescope. The plumes, illustrated in the artist’s concept above, were previously seen in images as extensions from the edge of the moon. Using SOFIA, we will search for water and determine if the plumes are eruptions of water from the surface. If the plumes are coming from the surface, they may be erupting through cracks in the ice that covers Europa’s oceans. Members of our SOFIA team recently discussed studying Europa on the NASA in Silicon Valley Podcast.
This is the view of Jupiter and its moons taken with SOFIA’s
visible
light guide camera that is used to position the telescope.
Filters are very important in astronomical observation as they reduce glare and light scattering, increase contrast through
selective filtration, increase definition and resolution, reduce
irradiation and lessen eye fatigue.
Working of a magenta filter
Depending on which object you are looking, one chooses the appropriate filter. For instance the cover photo is without and withthe moon filter.
And on an amateur telescope they is how they are inserted.
Telescopes like the Hubble have plenty of these filters stacked on them. You can find a list of the filters here.
Some popular filters commonly used are as follows:
Red – R
Green – V
Blue – B
Infrared – i’
Ultraviolet – u’
Hydrogen Alpha – H-alpha
Oxygen III – OIII
LPR (Light Pollution Reduction)
Neutral Density filter and so on…
Now here’s an image of the pillars of creation captured in various filters:
Observe that the maximum number of stars are visible in the B, V and r’(infrared) filters. Therefore, combining these three image yields a standard image like the one you find online.
That being said, in our next post, we will run through a quick tutorial on how to access the Hubble archive and retrieve any image with any filter of your choice.
The Crab Pulsar (PSR B0531+21) is a relatively young neutron star. The
star is the central star in the Crab Nebula, a remnant of the supernova
SN 1054, which was widely observed on Earth in the year 1054.Discovered
in 1968, the pulsar was the first to be connected with a supernova
remnant.
The optical pulsar is roughly 20 km in diameter and the pulsar
“beams” rotate once every 33 milliseconds, or 30 times each second
The above video allows you to hear the signal from pulsar and the gif below that is the actual pulsar blinking taken with a high speed technique known as Lucky Imaging .
Robert Evans is the world record holder for the most visual discoveries of Supernovae. Although he is a minister of the uniting church in Australia, he is better known in the Astronomy community as one of the ‘best Amateur Astronomers in the world.’
He is accredited for discovering 42 supernovas visually from his backyard!!
But, how on earth does he do it ?
Having been looking at the cosmos for years on end, Evans has memorized the entire star field and the positions of the galaxies in the night sky.
And as a result of this, he can detect changes in the galaxy simply by looking at them through the telescope.
Why is this remarkable ?
This is truly remarkable for two pivotal reasons:
A supernova is the explosion of a star. It is the largest explosion that takes place in space.
But spotting a supernova visually is extremely hard!
To give a perspective on the intricacies of supernova hunting, here is a picture showing the night sky before and after a supernova in Messier-82.
Supernova hunting in Messier-82
And secondly, he gave automated telescopes a run for their money. There are many telescope in recent times that automatically detect hundreds of supernovas every year.
But Evans managed to give them a tough fight in a battle against man and technology with his telescope sorcery.
A note for budding astronomers
Why I find Evans to be extremely inspiring is because here is an amateur astronomer doing quality contributions to Astronomy in his backyard and with not so fancy equipment.
Just shows how far passion and perseverance can take you in science.
But in the 21st century, there are many experiments (Coriolis effect, Foucault’s pendulum ,etc, etc) that you can do to convince yourself that the Earth is indeed rotating.
But back in the days of Galileo it was still debatable whether Earth was rotating or not.
Why does a ball thrown straight up in the air fall to the same place on the ground ?
One
of the profound Aristotelian arguments against the rotation of the
Earth was that if the Earth were rotating, a thrown ball/arrow would not
land in the same place that it was thrown.
This was believed so
because, by the time the projectile traverses its path the Earth would
have moved by a certain distance. Hence, the ball would never land at
the same place it was thrown.
Here
is an excellent argument given by Galileo in favor of the rotation of
the Earth and why things would still fall to the same place even if the
Earth were rotating:
In replying to this, those who make the earth movable answer that the canon and the ball which are on the earth share its motion or rather that all of them together have the same motion naturally.
Therefore the ball does not start from rest at all but to its motion about the center joins one of projection upward which neither removes not impedes the former.
You
will see the same thing by making the experiment on a ship with a ball
thrown perpendicularly upward from a catapult. It will return to the
same place whether the ship is moving or standing still
The profundity of this argument is that, the very same principle that ‘ball does not start from rest at allbut with velocity of the earth’ is used by space shuttles to reach orbital velocity with lesser fuel consumption.
But despite Galileo’s argument, it was still believed for a long time that it were the heavens that moved and not the earth.
For
God hath established the world which shall not be moved in spite of
contrary reasons because they are clearly not conclusive persuasions.
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