Siva Rathri with Sivan

           Astronomy with Binoculars              Clusters of the Celestial Sphere   Oh...what a Night show !

Early morning sunrise.

It was a different night. Cold much reduced, but dwe was condensing after mid night. The early evening till midnight was clear without any clouds. But haze in the atmosphere, made me rate it as 05 in the Bortle Scale. 

As with last fortnight, I saw, about to culminate Orion and Auriga. I lay in the reclining chair and used my 10x50 Binoculars to view Andromeda galaxy, in the western sector. It was not a difficult task. 

I could easily pick out M36 the compact bright of the three, just inside the eastern side of the pentagon. M37 a bit bigger and fainter to the outer side and M38 much bigger and fainter just west of M36, but much nearer than 37 is to 36. They formed a small non-equal triangle with M36 at the apex, in my 6 degree field of view. Sweeping down south and east I was able to see M35, at the tip of Gemini. A conspicuous loose cluster, looking like M38 but much brighter and bigger. 

Moving to Sirius and sweeping down south i could easily see M41. 

There were a couple of satellites for early evening, late evening and early morning totalling 10 in all. A couple of satellites crossed my binocular field criss-crossing in two directions, They looked brighter, faster, and nearer. There were a few meteors and high flying birds mimicking satellites.

Constellations Virgo, Lupus, Draco, Ursa minor, Herculus, Corona Borealis, Coma Berenices, Corvus, Ophiuchus, were traced full.

M4 was spotted near Antaras and M33 in Herculus.

Orion the Hunter (Greek mythology) - 

Lord Siva Nataraja  (Hindu mythology).

Modern statue gifted by India at CERN in Geneva, Switzerland.

The Dance of Shiva, this gigantic cosmic dance of vibrating molecules and atoms in the soil, air, rocks, water, and in our own bodies - this cosmic dance of energy, the rhythm of it is felt and the sound heard under the starry sky ! 

Colours & Intensity of some Bright Stars

Variable star BU Tauri, in Pleiades observed. I counted 11 stars in the group, with Binoculars. 

With the aid of Stellarium, we could locate Planet Mercury, currently in the constellation of Capricornus. It appeard as a bright steady untwinkling star with a golden hue. It was visible for sometime even when I missed the moon for a while. 

Its given Mag is - 0.29 with RA 20h 48m 50s & Dec -19° 22' 23”. Around 6 AM, planet Mercury appeared above to the north-west of a 2% lit waning cresent moon, being at the 11-o-clock position and the moon at 4-o-clock position in the same binocular field. Moon was stunning to look at nearar to the horizon in the moving partly dark cloud covered eastern horizon. For a few moments it was also seen with the naked eyes, along with the moon. 

Cropped screenshot of moon app showing a reduced to 1% cresent moon, on the same day, at 1.39 PM, Sun, 19th Feb, 2023.

Astrophotographers:-
Dr Suresh. (the equipment belongs to him). 

Visual Observers:-
Dr V Anand, Mr Renganathan, Dr Muralidharan - 10x50 Binoculars on easy chair, Collins gem guide, red filter torch light. Star hopping method. 

Telescopes used:
Dr Sureshmohan, Sudharsan, Syed: Takhashi FSQ-106EDx4 Quadruplet Refractor, on an astrophysics USA made mach 1 GTO.

Food & Hospitality: Dr Suresh, Mr Renganathan.

Dogs: local farm dog Brucelee. 🐕 

Photographs - choosen from the internet.

The Comet Cometh

 Jan, Sat 28 - Sun 29, 2023.

The Comet Cometh.

At last, we got a glimpse of the comet !!

C/2022E3(ZTF)

https://en.m.wikipedia.org/wiki/C/2022_E3_(ZTF)

(Borrowed from twitter)

I started early evening and went to the dark site immediately after sunset. Astrophotographer Dr Sureshmohan and Wild-life photographer Mr Vijayakumar, had reached the field before and had been busy setting up their equipment and other gadgets. I parked my car at a distance and had set up my binoculars, star charts and chairs for a night long observing session. 

The half-phased moon was high in the meridian. It was in Aries. As the darkness started to set in, the sky became bright with moon light and I could barely see pleiades and hyades that were so conspicuous a fortnight ago, from the same place. (Ref old blog article). 

The evening moon spoiled any chance I had with Andromeda let alone Triangulum. 

This time I saw Clusters that I missed last time. The sky condition was hazy throughout the night. Dew did condense but far less unlike last fortnight. It seemed to be held up as haze obscuring and clouding our perception of even clusters, let alone nebulae and galaxies. 

Late in the evening we were joined by engineer Siva Subramaniyam who brought an 8" dobsonian and Dr Muralidharan with cricketer Arun Karthick for the first time to one of our regular sites. 

This time we were lucky to have seen the comet, but overall it was a disappointing and frustrating night of hazy seeing. It became cold after midnight. I finally roosted in the car only to get up to see the comet as it neared the meridian.

Complete identification became impossible due to hazy sky and lack of sustained observations, with inbetween clarity and loss of clarity, switching on and off, letting us doubt our seeing objects with any degree of certainty. Nevertheless, I heard our friends shout aloud after getting sombrero and crab, etc., but their enthusiasm lasting only for fleeting moments of time with return of frustration due to haze that seemed to be boiling and spoiling our observations. 

The Observational Report. 

Binocular used: Celestron 10x50.

Artificial Satellite.

7.14 to 7.15

Sat crossed alnitak heading straight north visible only in 10x50,

a bit fainter than saiph. I tracked all the way north to 20 degrees above horizon. It became gradually fainter and disappeared.

Clusters seen.

Sword handle in perseus, 

M35 in Gemini,

m34 in Perseus,

M36, 37, 38 in Auriga

M41 in Canis Major.

M44 in Cancer.

M94 in Puppis.

M93.

8" Dobsonian observation.

Comet C/2022E3(ZTF).

The Comet was seen as in the picture here, with only one star below it in the telescope field. It appeared with a sharp point and Coma giving us the impression of a fanning out tail like a conic section, probably influenced by the photos we had seen of it in the fb groups. However, no color could be appreciated. After that, past the late midnight, it was seen near the meridian as it culminated west of Kochab in line with Polaris and the polar pointers of Ursa Major, with binoculars and unaided eye. But, only for fleeting moments of time before we began to doubt our perceptions. But, I am sure it seemed to have appeared in the Binoculars much more of a wide smudge than the sharp and small image it produced in the telescope ! And we couldn't see it !! Haze that kept moving and boiling and spoiling our vision. 

(Photos & Charts, courtesy: the internet)

Planets seen.

Venus, Jupiter, Mars, moon.

Stars seen.

Sirius, Canopus, Acherner, Betelgeuse, Spica, Bellatrix, Saiph, Alnitak, Alnilam, Mintaka, Sigma Orionis  Aldebaran, Castor, Pollex, Procyon, Adhara, Aludra, Wezen, Alceone, Algenib, Algol, Beta Tauri, Zeta tauri, Merak, Dhube, Mizar, Alcor, Arcturus, Regulus, Spica, Denebola, Porrima, Vindimiatrix, and finally after great hardship and after late midnight, Polaris and Kochab.

Constellations seen.

(Most of the prominent stars were  identified with binoculars). 

Cassiopeia, Taurus, Gemini, Orion, Canis Major, Canis Minor, Puppis, Perseus, Cancer, Leo, Virgo, Ursa Major, Corvus.

Star groups near some bright stars.

(Like landmarks, these can be called skymarks ! Let me call them "skymark associations").

> Algenib association.

> Algol association.

> Little Plough of orion.

Skymark associations are not so prominent like the known asterisms but, are nevertheless an easy way to remember the patterns. Experience says, every observational astronomer does remember the stellar patterns, in their own ways. In other words, sky mark associations are non-prominent sparse clustering of stellar patterns, spanning a few degrees in the sky, inside and across constellations. 

Asterism: (n) meaning,

> a prominent pattern / group of stars that is smaller than a constellation.

> a group of three asterisks (⁂) drawing attention to a piece of text.

Astrophotographers:-
Dr Suresh. (the equipment belongs to him). 

Visual Observers:-
Dr V Anand: 10x50 Binoculars on easy chair, Collins gem guide, red filter torch light. Star hopping method. 

Telescopes used:
Suresh: Takhashi FSQ-106EDx4 Quadruplet Refractor, on an astrophysics USA made mach 1 GTO.

Siva Subramaniyam: 8" tejraj dobsonian. 

Vijayakumar: 7x50 olympus binoculars.

Food & Hospitality: Mr Vijayakumar.

Visitors: Dr Muralidharan & Cricketer Arun Karthick.

Dogs: local farm dog kulla. 🐕 Brucelee was not seen this time. 

Post script.

I fouud in the facebook, British Astronomer David Graham has sketched the comet. It looks dramatic. Now, I am sure I saw it with my unaided eye inspite of haze, but only for a few moments.

Details given in fb by David Graham.

"Visual inner coma detail, Saturday morning 28th January 2023. Multiple striations visible in the tail of the comet."

Thank you.

Regards.

Dr V Anand,

Kanchipuram, India.

Astronomer Prof P Devadas, FRAS.

Professor P 

Devadas, FRAS.

A report of facts

350 mm Newtonian Reflector Telescope on Equatorial Mount 

(under construction)

I first met Shri Devadas with my late father Dr PD Venkatakrishnan, MBBS, DPH, MF Hom (Lond)., in 1986, at   the time of the apparition of comet Halley. It was a cloudy evening. We waited for long only to end-up viewing the take off and landing of flights at the Chennai airport,  situated in the western direction of his residence.    He told me to observe planet Saturn. It was in the constellation of Scorpious back then, in 1987. Indeed, planet saturn was a spectacle to observe ! Even today (in the days of space telescopes, spaceprobes, and the internet) nothing can match the beauty of planet saturn when observed through a small telescope. It is the first direct indicator of the resolving power of a small telescope !

Professor P Devadas, FRAS, the founder member of the Madras Astronomy Association who later honoured the Tamilnadu Astronomy Association as its President, was an Indian Amateur Astronomer (known throughout India), who commanded international reputation for his scientific work. 

He was an avid self-made Astronomer who made telescopes, grinding glass blanks with his own hands in his backyard, who later established an engineering firm manufacturing small to medium sized telescopes for the use of the interested common man. 

His equatorially mounted sturdy reflector telescopes are there in every nook and corner of this vast country. His telescopes are in Surendranagar, Gujarat as well as in  Calcutta, West Bengal. From the cities of New Delhi and Chandigarh in the north, to the temple city of Madurai in the state of southern tamilnadu. Some of his telescopes are in educational institutions and colleges, industries, schools and most of them belonging to private Amateur Astronomers.  

Nostalgia for me.....

I had spent many an evening and early part of the night, since 1986, observing the lunar and planetary phenomena, and even working for sometime, in the backyard workshop, grinding telescope mirrors, being instructed on the know how, by Prof. P. Devadas himself, and taking part in table work, on proof reading and analyzing lunar topographic formations. Those experiences I had, had indeed immensely enriched my mind.

Former Professor Ramakarthikeyan who was HoD, of the Mathematics department, at Swami Vivekananda College, once told an audience, that if they want to talk astronomy and do observation, they could always visit one place on Earth, in Guindy, Chennai, where the 24 hour astronomer Devadas lived ! (ofcourse, telephone first).

The British astronomer Richard McKim, FRAS, acknowledged in his mail to me, stating that he is 'glad' that I knew Prof P Devadas ! David Graham of the BAA, said in his fb comment, that the Indian astronomer Devadas was much respeced in the British Circles. That was his international reputation !

Total Solar Eclipse, Kalpi, Uttar Pradesh, 24th October 1995.

My work was to warn Prof P Devadas, as he photographed the eclipsed sun during totality directly by prime focus projection. I used another reflector telescope in which I had been observing the sun by indirect projection method. As the eclipsed sun advanced to a thin crescent, I noticed, it was cut into three parts by the jutting out of two lunar mountain peaks.

I also maintained a stop watch which showed time span of totality as 59 seconds, which tallied with the IIA measurements conducted separately there.

During the time of totality, I dared as preplanned, to observe the totally eclipsed sun directly through the telescope. I could see prominences of red fire emanating in regions around the darkened sun's limb. As time was short, I could only manage to see for a few seconds, the terrific view of nature's power and beauty.

Caution: the sun should never be viewed directly even with the unaided eye let alone dare to use a telescope or binocular.

Oh, what an awe inspiring view that was! Our lives became immensely enriched with unforgettable experiences that displayed nature's immense power, fury and beauty.

It was ecstasy but scientifically rewarding too!

Later, out team was awarded the first prize for eclipse photography by the 'All India Amateur Astronomers Meet,' held at Chennai the following year, with a cash prize of Rs.1,000/-

Total Solar Eclipse, Kalpi, Uttar Pradesh, 1995.

1st Diamond Ring

Total Solar Eclipse, Kalpi, Uttar Pradesh, 1995.

Mid Totalitity

Total Solar Eclipse, Kalpi, Uttar Pradesh, 1995.

2nd Diamond Ring

The Eclipse Telescope

The Eclipse Report.

face book post details Aug 22, 2017.

TOTAL SOLAR ECLIPSE

A total eclipse of the sun happened in the continental United States for the first time since February 6, 1979. In other words, the moon’s dark shadow didn't hit anywhere in the US or Alaska for 38 years.

The eclipse began over the Pacific Ocean at 15:46 UTC

The central line shows the track of total eclipse.

Great many fb friends living and visiting america have displayed their photos of this phenomenal scientifically rewarding natural event which has triggered my memories of the 1995 Indian eclipse. I had the good fortune of observing with a few amateur astronomers guided by Prof P Devadas, FRAS., a member of the British Astronomical Association. The eclipse was completely photographed and it also fetched us the first prize from 'All India Amateur Astronomers' meet held in Chennai city the next year. In fact, an article of this scientific expedition, was published in the 'Journal of the British Astronomical Association' by Prof Devadas.

I will try my best (in one of the future posts) to bring the photos and a small write up on the event for the benefit of all my fb friends, relatives, my good neighbors, colleagues, my teachers and students and above all, my long time astronomy enthusiasts and associates for our joy of knowing Nature at its splendorous best !!

Total Solar Eclipse Expedition, at Surendranagar, Gujarat, 1999,

with a British & two Japanese tourists who came to see the eclipse.

Total Solar Eclipse Expeditiion, at Surendranagar, 1999

Prof P Devadas, FRAS,

Sridhar

Ramalingam

Jaya Paul

(Sitting)

Satish Patil

V Anand

Sreekumar

An Expedition to the Lonar Crater, Buldana District, Maharashtra.

At the salty lake base of the Lonar Crater.

Prof P Devadas, FRAS,

Local School Headmaster

Sridhar

Murugan

V Anand

Satish Patil's Son

Satish Patil

Jaya Paul

Harry Miller's letter to Arthur C Clarke mentioning myself and Prof P Devadas

Prof P Devadas, FRAS, with other members of 

Tamilnadu Astronomy Association / Tanastro (Regd. 331/1989), 

at the BM Birla Planetarium attending the fortnightly members meeting.

Prof P Devadas, FRAS, with Star Party members of Tanastro.

Prof P Devadas, FRAS, with Star Party members of Tanastro.

Devadas use to send his observational work to the British Astronomical Association. He guided me in the observations of the favourable opposition of planet Mars, in 1988. Backvthen, the planet came to just 55 million kilometers distance, only three million kilometers short of its maximum nearer distance of 52 million kms. It was spectacular sight even with the unaided eyes to have seen planet Mars that bright. It was like Venus in brightness, but unlike Venus it shown in red light in the middle of the night, high above. 

Devadas appreciated my Mars images showing the shrinking of the polar ice caps spanning a period of three months, indicating the advancement of summer on the planet. 

Much later, we had many astronomical events that came up, including, the crash of comet shemaker-levy on planet Jupiter, total solar eclipses of the sun in Oct 24 1995 and 1999, followed by Mercury and Venus transits across the sun and many more events of astronomical importance.

FYI. "For Sir Patrick Moore's tribute page." (facebook).

The extract is self-explanatory. It is ample proof of the straight-forwardness and scientific honesty of the great British astronomer Sir Patrick Moore, CBE, FRAS. The 1962 paper in BAA journal, clearly testifies the depth of knowledge and expertise gathered through telescopic observation of the lunar surface, by Prof. P. Devadas, FRAS, whose meticulous observation of the lunar surface through his telescopes and interpretations of the same, were in concordance with that of Dr Moore.

I have personally known for more than three decades, since my college days, the late Shri P Devadas, Selenologist and Observational Astronomer, Telescope Manufacturer, and Science Activist, Chennai (who was dear to Dr Moore) which I cherish till date. Of late, his daughter Mrs Komala Murugesh has been continuing to do the good work of Shri Devadas. In the interest of all aspiring astronomers, i share my private collection.

Thank you.

Regards,

Dr V Anand.

Devadas lectured with a hammering voice, and explained his scientific arguments with conviction and clarity and with an authority of experience, brought about by his life long devoted experience in observational astronomy and telescope making. 

Once when i opened the main door of our chennai BM Birla Plaanetarium, i was stunned by his reverbarating voice, lecturing on the origin of craters, his passionate subject. Hs was an invited, regular speaker, of the madras Planetarium. He was in the capacity of a resource person, whom the planetarium staff of the government, could rely upon. 

I found him to be an  amazing man of great character, integrity, with a persistant silent perseverance, with time tested audacity and even seemingly eccentric behaviour when it came to dealing with ordinary people, who are mostly influenced and conditioned by the pseudo-science of astrology. He never showed his intellectual greatness with ordinary people. He was a down-to-earth man, his mannerisms looked enjoyably funny to most of us, his students, who were dear to him as we  paid regular visits to him to learn astronomy. 

To be updated further....

In a dialogue with myself

A Spiritual Poem

"The arrows of time cry here 

when the archer is elsewhere."  

     I dig deeper; I dig deeper; 
I am fired up; I am fired up. 
I am He; I am He. 
I fear not death; I love; I love; 
I am the enlightened, yes, I am.

Give love, give love;

Craving for love is desire;

So, just give love; give love.

Love has its own action.

Give love; give love,

It is only the giver who is blessed.

Give love; only give love.

Its only the giver who is doubly blessed.

Give love, do not take it; 

Give love not to receive it back.

Do not yearn for uncoming love,

For most people are too frightened.

Give love, give love,

Love thy own self !

They fear the impending death.

And form fear unions to face death !

Give love, do not crave for it;

Most are even incapable to receive it !

Nevertheless, give love.

Give love; do not take it !

It is love that liberates;

It is love that breathes fire;

It is love that even decides to desire !

Have heart; Have heart;

 Have affection; Have affection.

Freedom is the flavour of love;

In freedom does love flower.

It's the receptacle.

Have freedom; Have love.

Love liberates; Love rejuvenates,

Love loves, Love cares.

Love life, love all,

Love death.

Love is the mother; Love is the father.

Love is the sister; Love is the brother.

Love is the guardian angel,

Love is the care taker.

Love is strengthening;

Love is Heartening,

Love is liberating.

Love is our breath.

Love is the doctor who treats;

Love is the patient who heals.

Love is the teacher who teaches;

Love is the priest who preaches.

Love is the mother who cares;

Love is the father who dares !

Love is the guardian who guards;

Love is the lover who cares.

Love is that archer,

Who sent forth the arrows of time-

To cry their stories of pain,

Hitherto, unheard of.

Give love, give love;

Craving for love is desire;

So, just give love; give love.

Love has its own action.

Pongal Star Watch

"Astro Yoga"

From the desk of the Teacher.

Sky Scraping on Sankranti Night !

       "Astronomy a good hobby for all generations"

Sunrise 

Astronomy with Binoculars 

Sunrise - the blazing Sun !

Dt: Sat-Sun, 14-15th Jan, 2023.
Place: Vembakkam village farm.
12°58'5.11"N; 79°34'55.73"E.

IST: 7 pm - 12.30 am.
UT: 1.30 pm - 6 pm.
Binoculars used: Celestron 10x50.

Observers: Dr V Anand, Mr A Aravind, Er Arun Venkataswamy, 

Dr Sureshmohan, Wild life photographer Mr Vijayakumar, Mr Guru.

High thin clouds and a hazy evening, cold, and dew condensing, noticeable on cars and instruments and on the easy chair. The dew became noticeable by 12 midnight, heavily condensing on the cars wind shield. I reminded Aravind to use his head cap as he was attempting to image the Milky Way, after mid night.  

Constellation Orion was in the eastern sky and Canis Major culminated the meridian at the close of our observing session  after mid night. It became very cold, hazy, with dew condensing. 

Astronomy, is the basis of all our calendars of all civilizations, either occidental or oriental. It is the basis of many religious philosophies. Our seasons, weather, rainfall, and agricultural production, are dependant on the annual periodic shifting of the stars and constellations, as the Earth revolves around the Sun.

Stars seen: Acherner at the far end of the southern sky, Betelgeuse, Rigel, Bellatrix, Saiph, Alnitak, Alnilam, Mintaka, Sigma orionis, Lambda orionis, Sirius, Canopus, Castor, Pollex, Procyon, Aldebaran, Merak, Dhubae, Polaris, Regulus, Denebola, alpha Andromadae,  variable star Algol, zeta Tauri, etc.,

Contellations seen: Pegasus, Andromeda, Cassiopeia, Perseus, Orion, Auriga, Lepus, Canis Major, Vela, Canis Minor, Aries, Triangulum, Taurus, Gemini, Leo, first part of Ursa Major (1st three stars). 

Messier objects: 

Star Open Clusters: M45 Pleiades, Hyades, M37, M36, M38 in Auriga, M31 in Gemini, M41 in Canis Major.

Galaxies: M31 Andromeda galaxy, M33 Triangulam galaxy, and 

Nebulae: M42 & M43 the great Orion Nebula. 

Planets: Venus, Jupiter & Mars. 

A couple of satellites were seen passing slightly towards the north-east noticed starting from near the northern half of orion in the early evening. The satellites were tracked  for a much longer time through the Binoculars. A faint streak of a meteor was seen too. 

Polaris presented no difficulty from the beginning. 

Orion nebula was so conspicuous as usual. 

Andromeda galaxy was easy to find and on persistent observing with averted vision I could appreciate its extended hazy envelope surrounding its compact fuzzy nucleus. It looked like a stretched fuzzy oval in the east-west direction with a condensed fuzzy nucleus at the middle in the Binoculars. 

Triangulum galaxy, presented some observing difficulty. I became conscious of its faint presence with sustained observation after zeroing-in-on to the exact spot. Time was around mid night. I remembered, seeing it at its best, at 3 am,  high and  having culminated the meridian, many years ago, from Ramencheri dark site, with Mr Renganathan, my star hopping companion. It was a rare show then. 

Since, this event happened after a gap of two years, all our friends of different interests and activities, looked a bit worn down, and some felt body pain and not at ease to the demanding and strenuous work out in the field. A lack of agility, weight loss or gain, fatigue and body pain had set in. 

Astronomy in the field demands physical fitness, mental fitness, seriousness, intense interest, persistent purpose, attentive quality to the minutest of details, powers of concentration, agility, technical skill and expertise, interpersonal skills, a silent predisposition minding your own work, helping and educating others in need, non-disturbance, environmental awareness, etc., 

Indeed, it's a kind of Yoga - "Astro Yoga."

And, "star hopping" is a best meditative 

exercise ! The late Sir Partick Moore, CBE., FRAS., said, his friend George Alcock,  remembered some 30,000 stars by memory like many Indian yogis of bygone days ! 

It is said that Vararuchi an ancient Indian astronomer, spent forty years in star-gazing lying on a rough cot gazing at the stars. One night a disciple of his, introduced an extra bed sheet to make the bed more soft. Then Vararuchi immediately felt the change in the height of his bed and asked his disciple whether the sky had come down or the earth had gone up. Such was his adaptation. Now, we know where we stand ! 

(Ref. Popular Astronomy, by Professor V Thiruvenkatacharya, 1958).

Doing that  regularly atleast twice a month, one can ensure physical and mental fitness.  And it's a religion of cosmic dimensions.  It takes you straight to the beginning of everything, material, time and consciousness !

"If You Are With NATURE With All Your Senses You Are Never Alone."

Let's meet God !!!

Astrophotographers:-
Dr Suresh & Er Arun (the equipment belongs to them). 

Mr Aravind, mobile phone imaging.

Visual Observers:-
Dr V Anand: 10x50 Binoculars on easy chair, Collins gem guide, red filter torch light. Star hopping method. 

Telescopes used:
Suresh: Takhashi FSQ-106EDx4 Quadruplet Refractor, on an astrophysics USA made mach 1 GTO.

Arun: Custom designed camera mount.

Vijayakumar: 20x100 bino with custom designed mount.

Participants: Mr Thanigai.

Dog: Brucelee.

Early Morning Tea

> The blog will be updated further, after some image processing.

Black Holes

Black Holes in Space

The Milky Way Galaxy's Central Black Hole called "Sagittarius A," has finally been imaged !

Eventhough it is in excess of 4 million solar masses, it is nothing compared to the colossal 6.5 billion solar masses of that supergiant elliptical external galaxy designated M87, that was imaged in 2019, in the constellation Virgo.

Black Holes were predicted to exist by the theory of general relativity propounded by the great theoretical physicist of all time, Albert Einstein, in 1915.

When the end product of a massive star breathes its last nuclear breath, it either ends up as a White Dwarf star (upto 1.4 solar masses, as derived by the nobel laureate Subramaniyan Chandrasekhar) or a Neutron star (upto 3 solar masses) or a Black Hole (> 3 solar masses), only depending on its final end mass.

A Black Hole is the end product of a massive star which got exhausted of its core nuclear fuel. What happens is, when a massive star dies, it collapses due to its inwardly acting gravitational field.

Stars are burning balls of emanating electromagnetic radiation, generated in their cores by nuclear fusion reactions. In its prime life time called the "main sequence time," a star is balanced by the inwardly acting gravitational force countering its enormous radiation pressure, escaping outward from its millions of degrees hot centre.

With the passage of time (i mean, cosmic time scales - of millions and billions), stars get exhausted of its hydrogen nuclear fuel, and succumb to the inwardly acting gravitational force as the outwardly acting counter-balancing radiation pressure gets depleted. Now, a star collapses on itself and gets reduced in radius.

The collapse is of such magnitude that the stars atoms get closely packed to one another. It gets into a state of electron degeneracy where the atomic electrons resist further collapse. A star like the Sun, shrinks to a radius of a planet like Earth. It becomes a high density star called a "White Dwarf star." This as the name suggests is a dwarf in terms of its size and incandescent white in terms of its surface temperature. It burns by a process called "triple-alpha process," in its core, and is supposed to live for a few million years, till it reduces itself further into many stages towards a final state of becoming a blown-out brown dead stuff.

Suppose, if the end product of a post main sequence star, is more than 1.4 solar masses, as defined by the chandrasekhar limit, it turns out into a Neutron star. How ?

As I said, the white dwarf star is in a state of electron degeneracy. In a massive body of > 1.4 solar masses, the orbital electrons are forced to break down. The atom ceases to exist and becomes only nuclear matter. The electrons fuse with the protons and become neutrons. It is called a state of neutron degeneracy.

The entire star is composed of only neutrons. Its radius is enormously reduced. It's just like, if the planet Earth, all of a sudden, became a small island ! A spoon-full of its matter now, weighs billions of tons !

These neutron stars, that rotate super-fast are also called "pulsars," and these radio-pulsars, are picked-up by radio telescopes on Earth. The famous Crab pulsar, is located within the crab nebula supernova remnant.

Super-Novae, are gigantic explosions of the end products of massive stars, before their core collapses into a neutron star.

And don't forget, our Sun is a star, but, its not likely to explode into a supernova. It will slowly swell up to gigantic proportions to the extent of gobbling up the inner planets, becoming into a red giant star and even becoming a red-supergiant star with a luminosity of ten thousand suns, only to finally expel it's extended atmospheres, to leave a remnant nebulae. After these stages, it will end up finally, into a white dwarf star, in another five billion years. These are theoretical astrophysical predictions, from well-established models of observational studies of

"stellar evolution."

Well then, what is a Black Hole ?

When the end product of a massive star is more than three solar masses, a star remnant collapses into a Black Hole. Even light with its fabulous velocity of 300,000 kms/s, can't escape from the gravitational field of a Black Hole. How can we see it ? Simply, we can't see it exist in any part of the EM spectrum, other than by its attractive gravitational field. They were predicted to exist indirectly by the behaviour of its nearby stars. But, now with advanced imaging methods and technology, scientists have been able to image its location negatively, by imaging the infalling surrounding gas that emits EM rays before its final disappearance into the Black Hole, all around it circumferentially.

The Black Hole is simply a space-time region of a finite mass of the end product of a massive star that turned into a point of singularity a mathematical proposition, which has an infinite density, infinite temperature and infinite pressure.

It's gravitational boundary is called event horizon. Any thing including light that enters it is doomed to be ever within it. Its gobbled up for good. Actually, there is only empty space between the event horizon and singularity.

Black Holes are regions of collapsed space-time itself due to the presence of not only mass, but singularities. They are supposed to be of many kinds. Stellar black holes, relic primordial black holes of the big bang and supermassive black holes at the galactic centres.

M87 and Sagittarius-A are SMBHs.

- to be continued....

...this writeup is not a forward or cut copy paste. It was written spontaneously.