Hanle Dark Sky Reserve (HDSR)

Star Party October 2023

 

"Who are we? We find that we live on an insignificant planet of a humdrum star lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people."

- Carl Sagan

 

When I stepped out in the dark night fully attired for the bitingly cold weather, looking like an astronaut on a gingerly spacewalk, the first thing I noticed was how dark and ‘full of stars’ it looked overhead.  As I reached the open field with several telescopes already laid out to receive the precious light from above, dark adaptation of the eyes also achieved in the normal course, the marvelous sight overhead and all around began to unfold and sink in slowly. I thought I had exhausted my linguistic talents while describing the total solar eclipses I had seen before, but this required additional ones that I was too human to possess.  So, let me not even try, except to say that it was unlike anything I had ever even imagined.  To say that the Hanle dark sky that night merited a perfect 1 under the Bortle scale would be too prosaic, and perhaps too technical as well, to appeal to one’s sensibilities!

What happened next? The reader will have to wait for the events to be unveiled in due course…

Prelude

Referring to Carl Sagan’s famous quote above, for the uninitiated, the insignificant planet is our own Earth, the humdrum star is of course the Sun, the galaxy in which it is ‘lost’ is the much-loved Milky Way, of which we are a part, and modern astrophysical techniques do allow as to determine where the Sun is tucked away in the vast galactic Universe that we are able to model today, a model in which a galaxy is itself nothing more than a speck of cosmic dust.

If indeed we get ‘lost’ in our (barred-spiral shaped) Milky Way galaxy, astrophysical techniques may again help us to ‘return to Earth’ as the following detailed map of the Milky Way based on the Sloan Digital Sky Survey suggests.  (On seeing this visual, one of my colleagues with a refined sense of humour remarked that if you ever get lost anywhere, you'll still be lost in the Milky Way!).

An average sized galaxy contains about a hundred billion stars, and it has been recently estimated that there are about 10 trillion (one trillion is a thousand billion) such galaxies in the observable universe, definitely a great many more than the population of our planet!

When we look up at the starry firmament in the night sky, what we see are mostly the objects belonging to parts of that ‘galaxy tucked away in a forgotten corner of the universe’, viz, the Milky Way. Practically all the (trillion) other galaxies are so far away from us that our eyes can’t even see them. They have become the preserve of telescopes since the time of the great Galileo.

The Starry Firmament 

Night Sky Watching is one of the oldest hobbies of human beings in any part of the world, at any time of the year, and with or without optical aid such as binoculars and portable telescopes, the only expectation being clear skies with little or no light pollution.

I have been a night sky watcher, and an amateur astronomer as well, ever since I was mesmerized by the vision of the great comet Ikeya-Seki in late 1965, just a year after I had joined the Regional Institute of Education in Mysore.  My newly discovered hobby had been fueled by incredibly clear and unpolluted night skies all around the institution’s large campus, and over a vast area surrounding it, including the sprawling Mysore university campus.  I was particularly fascinated by the richness of the southern skies and the breathtaking beauty of the Milky Way.

My surroundings and viewing conditions remained virtually unchanged for the next two decades at least, before being overtaken by the ravages of urban ‘development’.  What was once a beautifully green foliage has now been transformed into an ugly concrete jungle. The fact that I now live in the heart of the city, with severe light pollution, though otherwise agreeable, has virtually killed my hobby except when I get the chance to move far away from the city to distant dark sky locations. Luckily, such occasions have not been too infrequent.  A recent one was an all night sky watch party in February earlier this year, to Gavi Betta, in the Western Ghats of Kodagu district in Karnataka. The latest and the most exciting one, to the Dark Sky Reserve at Hanle in the union territory of Ladakh barely ten days ago, is the subject of this blog article.

The Invitation

Not unexpectedly, I received the following message last month from Dr Niruj Mohan Ramanujam (Niruj for short), Head of IIA-SCOPE and one of the organizers of the Hanle Dark Sky Reserve Star Party:

Indian Institute of Astrophysics, along with the UT Ladakh and LAHDC Leh, has great pleasure in inviting amateur astronomers of India to the Hanle Dark Sky Reserve for the HDSR Star Party 2023, between 12th to 15th October 2023.

Hanle Dark Sky Reserve (HDSR) is India’s first dark sky region, and is centred at Hanle in Eastern Ladakh around the Indian Astronomical Observatory (IAO). IAO is a research facility that is run by the Indian Institute of Astrophysics and has one of the darkest skies in India. HDSR preserves the dark skies by reducing light pollution and uses these dark skies to promote Astro-Tourism as a means to further enhance socio-economic development in the area. This is achieved through providing telescopes and training to selected villages, and these HDSR Astronomy Ambassadors function as astro-tourism guides for visitors.

Please note that this star party is not for beginners, but for amateur astronomers with some experience.

Hanle is a remote location at high altitude, and hence we have provided certain guidelines and precautions to be followed by everyone. These are for your own safety and health and we urge you to take these seriously. We have listed various information about logistics. You will need to book your own accommodations at local home-stays and an initial list of them is given in the document below.

Leh

Duly invited despite my advanced age, I embarked on the second step of my long journey to Hanle, by an air journey from Bangalore to Leh via Delhi on the 10th of this month.  Flying over the Himalayan Mountain range on the way to Leh was as thrilling as a similar journey over the southern Andes not too long ago. Looking out through a window-side seat, I kept my smartphone camera busy all the way up to Leh airport. Here is one of the pictures I shot in that flight: 

At Leh, the local organizers led by a boyish looking engineer and astrophotographer Mr Dorje Angchuk (Dorje for short), head of the establishments at Leh and Hanle, had arranged for me to be accommodated in the office-cum-guest house of the Indian Astronomical Observatory (see picture below), a part of the Indian Institute of Astrophysics with headquarters in Bangalore. 

The guest house, situated close to the airport, commanded a spectacular view of the mountain range beyond the airport. Here is a zoomed-in view I captured from the balcony of my room: 

There was a virtually mandatory two days of confinement at Leh* (altitude 3,500 m) for acclimatization to the prevailing high-altitude conditions. In the company of Dorje and Niruj I managed to sneak out for about an hour for some minor purchases, and see a few scenic parts of the city in the process, though I was not able to do a full-fledged tour. However, there was little by way of physical activity on my part during this brief outing.

[*Part of the health advisory states: “On arrival by flight at Leh, take full rest for 48 hrs without much physical activity as otherwise it will increase the risk of altitude sickness. Complete rest for 48 hrs will allow your body to adjust to high altitude conditions.”]

Leh to Hanle

On the morning of the 12th, two minibus loads of HDSR star party participants, including me, left on a long road journey of over six hours from Leh to Hanle (altitude 4,500 m), a distance of about 250 km in the southeast direction in the hilly terrain (see map below). 

Aided by glorious weather, with brilliant sunny skies, the scenery was spectacular all the way, with the Indus River and its banks for pleasant company much of the way initially, and the Hanle river towards the end. On the way we stopped at many places for photo-ops. Here is a keep-sake picture of me standing right next to my minibus carrying the official star party banner: 

Half way into the journey, we got down for a road-side lunch break and noticed the following captivating banner prominently displayed some distance beyond the highway: 

We got close to the fascinating hot spring described so glowingly here and one thoughtful participant captured the following video clip showing the hot spring in action:

As we neared Hanle, the scenery around us became even more incredibly spectacular, often surreal, and I am as much at a loss to make a judicious choice of my next picture as to put into words what I saw around me.  I am settling for one showing all other occupants of my minibus, each lost in thought or some course of action, too far away to notice my snooping.

 

HDSR

Soon we were inside the large area (roughly 22 km in radius centred around the Indian Astronomical Observatory) designated officially as the Hanle Dark Sky Reserve (HDSR) and the base camp of the observatory that houses the local offices and guest house. Below is a view of the facility (at center-left of the picture) I captured from a distance.  (The brilliant blue cloudless sky was a constant daytime companion). At lower right is a large Cerenkov gamma ray detector facility known as MACE. 

I was housed in a room at the guest house as comfortable as the one at Leh, minus the spectacular view through the window. 

Close to the IAO is a majestic Buddhist monastery (see picture below) on a hillock, a prominent local landmark. 

Wonders of the Hanle Sky

The party had attracted over thirty serious amateur astronomers in small groups, representing all parts of the country, most of them coming with their own telescopes, large and small, with the organizers providing logistic support. They included the leading lights of Indian amateur astronomy and astrophotography, Ajay Talwar and Neelam Talwar, with a legendary reputation behind them.  Most of the participants had also found living accommodation in homestays that had been identified and encouraged specifically to cater to the needs of the party, which was arranged in the large open area adjacent to the base camp of the IAO.

When I stepped out fully attired for the cold weather, Niruj helped me walk the short distance in almost total darkness, something I was not fully prepared for, even with a handheld torch light covered with red cello paper.

With my gaze turned fully skyward, initially I couldn’t even make out some of the more familiar constellations since the limit of human eye visibility could have been a couple of magnitudes higher than normal. I had difficulty even recognizing Saturn. Then the familiar figure of Cassiopeia and the Square of the Pegasus became recognizable, and within a short time, I could begin to make out other constellations as well, especially Cygnus overhead.  The Pole star which is rarely recognizable at Mysore nowadays was shining brilliantly, at least 20 degrees higher than at home.  Pleiades was just rising on the horizon, large and dazzling, and I wish I could have seen it much higher up.

A few participants started showing some of the more treasured sights through their telescopes at least one of which was a huge Dobsonian, possibly 16” aperture.  He showed Saturn like I had seen never before despite the none too favorable cross section it now presents to viewers. Another was a 14” vintage Meade through which I saw both Jupiter and the Andromeda Galaxy, which was also a visual spectacle. Other objects I could see through telescopes that evening was the M15 Hercules globular cluster, and a few bright open clusters in Sagittarius.

But my most enduring memory of that night was the incredible view of the Milky Way, stretching from horizon to horizon, including its densest part through Sagittarius and surroundings, visible like never before to my eyes.  In fact, if ever a celestial object looks to the naked eye exactly like what one sees in some expensive glossy textbooks in Astronomy, the view of the Milky Way I saw was just that. Incidentally, the lead picture at the beginning of this article is that of (part of) the Milky Way captured by the Talwars on one of those nights at the party. 

I had been under the night sky for about ninety minutes before Niruj announced that it was time for dinner and we could return to the field for a long night session thereafter.  As before, he led me up to a point and went ahead of me after assuming that I could find my own way.  Till then I had suffered no discomfort whatever and had no inkling of what was to happen to me half way back to the guest house. Then it happened all of a sudden and totally unexpectedly.

The break

I suddenly felt extreme difficulty in continuing to walk back and began to breath heavily after each step I took.  I forced myself to stand still for a short period before taking another step, and even this was quite hard.  After repeated short breaks like this, I managed to get back eventually to the building and then on to my room where I felt so exhausted that I had to take a long rest before going for a late dinner.  After dinner, I narrated my experience to Dorje who asked me a number of searching questions, advised me to forget the post dinner visit and rest completely overnight, and promised to review the situation the next day. Next morning, when I reported to Dorje that I felt rather tired in spite of a great and uninterrupted sleep overnight, he asked me to continue to rest indoors with frequent intake of oxygen for which they had a portable supply machine. 

Before dinner that evening, Dorje himself conducted me to the observation area and it was soon clear to both of us that I was seeing nonexistent phenomena in the sky that made no sense at all. In that delusional state of mind, it didn’t require much convincing that I was suffering from some kind of altitude associated sickness. He escorted me back to my room, put me on oxygen and advised me complete rest after a quick dinner. Again, I slept well, apparently free of all disturbing symptoms the next morning.  However, it was Dorje’s considered opinion, backed up by his long experiential evidence, that I should return to Leh (about a thousand meters lower in altitude) as soon as possible. 

Realizing that I had still not been able to visit the nearby observatory further uphill with its iconic 2 m HCT (Himalayan Chandra Telescope), he organized a quick trip for me, cautioning me not to climb up the stairs to the upper level of the telescope.  Here is a keep-sake picture of me against the background of the telescope before I returned: 

The End

At this juncture, I deeply regret to say that I was in no position to take any further part in the night sky observations at the Hanle party and had to return to Leh prematurely on medical advice. The circumstances that led to this course of action and the events thereafter will be explained in greater detail in my next blog posting after first submitting a formal report to the organizers on the issue.

[I later learnt that I was not the only one to be afflicted with some sort of altitude sickness. There were a few others as well, at least one of them needing hospitalization locally and subsequent return to Leh.]

When I embarked on the journey to Hanle, for logistic reasons I had not planned to carry any of my own telescopes with me.  In any case, my interest was purely in visual observations, preferably supplemented with a 50x10 Olympus binoculars I had carried with me.

Some Astrophotographs

Any account of the HDSR Star Party would be incomplete without reproducing at least a few of the superb astrophotographs captured by the expert amateur astronomers with their treasured equipment, especially their large aperture telescopes that are never easy to transport.  I am reproducing some of them here with grateful acknowledgement to the hardy people who made them possible, particularly the Talwars. 

[A monochrome picture of the Andromeda Galaxy]

[Above: False Dawn & Milky Way. Ajay Talwar had alerted the party to the possibility of this spectacle – A triangular arching doorway, the left side of it formed by the Zodiacal Light, with Venus shining brightly.]

[Andromeda Galaxy]

[With the HAGAR gamma ray telescope in the foreground. Smartphone picture by Abhinav]

HDSR Party and the HCT

While I was on my return journey to Hanle, the rest of the group visited the Observatory and spent quite some time at the HCT.  Here is a group photograph taken at that time: 

Here is a great picture taken by Abhinav inside the dome of the HCT where its optical and mechanical components can be made out, with most of the visitors in the foreground. Of course, I couldn’t be part of this group! 

Acknowledgments

The limited time I could spend observing the incredibly fascinating dark night sky at Hanle gave me much of the excitement and experience I was looking for and I have no serious regrets that I couldn’t be a more active member of the party. Even this limited participation was possible due to the courtesies extended by the organizers, in particular by Dorje and Niruj (see picture below, Dorje on the right). I am immensely indebted to them. 

I am also indebted to Ajay Talwar (see picture below) for previewing a draft of this article and offering some very valuable suggestions for its improvement.