Stairway to Night Sky – The Hanle Effect

I have always been fascinated by what the skies looked like to the naked eye before the artificial lights flooded the planet. How spectacular would the skies have been? My first conscious effort to gaze upon the skies started from Coimbatore. Astronomers use the ‘Bortle’ scale that rates the sky from a location from 1 to 9 based on how much light polluted the place is, 9 being the most light polluted and 1 being the least. More light polluted the skies, the less of what one can see in the sky. Coimbatore falls under Bortle 5 category. The metros like Bangalore or Mumbai or Chennai will fall under Bortle 8 or Bortle 9 skies. Remember there was a time in history where the entire world was Bortle 1 skies.

Once your brain is fed with this ‘Bortle’ knowledge, there is progressive decline of peace unless you climb your way up the bortle scale all the way to Bortle 1 skies, at least once. Being in Coimbatore means easier access to the forests of the western ghats, like Mudhumalai forests which fall under the Bortle 3 skies. Bortle 3 skies are brilliant. You can start seeing the milkyway galaxy band clearly with the naked eye. But what would Bortle 1 look like?

I have been associated with the Bangalore Astronomical Society (BAS) since 2019, which is home to a unique subset of homo sapiens who exhibit high functional ability once the sun goes down – a nocturnal subset. The star parties by BAS are an absolute delight, not just for the choice of location, which is usually Bortle 2 skies, but one gets to meet this nocturnal subset of people. The year 2022, would be my year to climb to the top of the Bortle ladder, and thanks to BAS and Indian Institute of Astrophysics (IIA) for arranging an official stargazing party to Hanle, which is proposed to be India’s First Dark Sky Reserve.

From left to right: Me, Ganesh and Aishwarya

Hanle is a small village located at about 4200m above sea level in the Himalayas (Ladakh). The entire region is a high altitude dry and cold desert, and yes, most certainly physically challenging conditions for observing or imaging the skies. About 15 of us from across the country, who were up for it mentally and physically, signed up for this pilgrimage, as we would like to call it. From Coimbatore, there were 3 of us: Me, Ganesh Raja and his daughter Aishwarya. We coordinated and spent at least about a month to get everything that was needed for the trip, from the warm clothes for the subzero temperatures to packing our imaging equipment securely for air cargo. The air cargo reached Leh a few days earlier, and Mr. Dorje Angchuk of IIA generously received them and kept them safe at the IIA Guesthouse. The day we had to leave was finally here: 20th Sept 2022. The route was Coimbatore to Leh via what looked like a never ending layover at Mumbai for over 9 hours. Our flight to Leh from Mumbai was at 03:30 AM, and we were finally relieved to be in the flight.

View out plane window just minutes before landing

As the flight approached the destination we could see snow capped mountains everywhere, with small patches of greens here and there, and finally the plane did land without any trouble. I am mentioning this here because on the same day, a few hours later, two other flights that were supposed to land were turned away due to bad weather. 7 of our team members who were on those flights lost an entire day stuck in Delhi.

We stepped out of the flight. The time was 06:10 AM or so. We are at an altitude of 3500m above sea level. It was very cold. We hired a cab and quickly moved towards the IIA guesthouse. The first warm thing we encountered were the warm greetings of Mr. Suman and Mr. Tsewang Dorjai who took care of our air cargo and also guided us to load it on a cab. We started moving towards Stok, another village located about 20 km from Leh. We arrived at Chomal cottages where we would spend the first 2 nights to acclimatize before we could move to a much higher altitude Hanle. The second warm thing we encountered was the butter tea that lovely hosts of Chomal cottages gave us.

Milkyway from Stok Village

The weather was initially bad with very dark rain clouds all around, and at about lunchtime or so it even started drizzling. The ambience became colder. I was tired anyway, and slept through till the evening. At around 07:30 pm the sky was crystal clear. I had not seen anything like that before in my life. I could see the milkyway galaxy arm extending almost two thirds of the sky from the southwestern horizon. Just before falling asleep, I checked my oximeter reading, it was 92. Quite normal in those conditions.

The second day the plan was to go to Leh market to purchase any items that would be required for the Hanle journey. The rest of the team also arrived on day 2. Before we could leave for Leh market, two of my dear friends Stanzin and Samyuktha, who run Earth Building startup were doing a 10-day workshop, which was about 300 meters from where we stayed. We dropped in to say hi, and spent about an hour in the workshop. They also visited us the same night for a small stargazing session. I must say both the nights at Stok have been nothing short of brilliant. Both Naveen and I were up until 01:00 AM on both the nights at Stok. I was wondering to myself ‘If Stok sky is already this brilliant, what could Hanle offer?’

The Buttery Road to Hanle

The day that we will journey to Hanle was finally here: 23rd Sept 2022. The skies were still brilliant in Leh and Stok, but the news was not good for Hanle. The weather was bad, and was predicted to be bad at least for another week. That is indeed bad news given that we would be spending only about 5 nights in Hanle. But we pinned our hopes on the uncertainty in the weather prediction models and we moved ahead. We had no other option anyway.

The journey to Hanle was one of the most memorable road trips with smooth roads and beautiful landscapes throughout. We arrived in Hanle at around 06:30 pm, the skies were completely blanketed in clouds. We put our equipment in IIA guesthouse and settled in our rooms at a homestay called the Milkyway located about 700 meters away from IIA. It started drizzling. It did not stop for a very long time. Anyway most of us were tired and we just slept like logs that night. Just one more thing, my oximeter read 88, which I was told was quite normal at that altitude, and my heart rate was between 110 and 120, which was quite high given that I am just resting.

The IIA facility in Hanle

Next day Sudhash, Naveen and I rushed to HCT after breakfast to send messages to all our families about our arrival. Naveen and I spent the next 90 minutes or so exploring the HCT in detail. What a piece of work that is with a huge 2 meter primary mirror.

Post lunch, Ganesh, Aishwarya and I decided to unpack our astro equipment and start setting up. We finished 70 percent of the setup and Ganesh even took a wonderful time lapse of it. The drizzle and the Sunset forced us to stop and cover up all our equipment for protection from the rains and dust. We called it a day, and the weather remained bad through the night. 2 out of 5 nights at Hanle are already washed out, with weather apps predicting no good news for upcoming days as well. We kept doing things keeping in mind if skies open up and starlight floods Hanle, we don’t want to miss getting drenched.

From left: Me, Ganesh and Naveen. Image credits: Zeeshan
My Astro Imaging Setup

The third day greeted us with a gloomy morning with fresh snowfall that covered the surrounding mountains. But there was this prediction that skies might be briefly clear tonight. The Coimbatore trio continued to finish the setup. We did a rough polar alignment of our setup, and covered it up again. While we were doing this, the skies were brilliantly blue, and we were hopeful. 

By around 07:00 pm or so, the skies darkened and we could already start seeing stars in the sky. The APers are interested in this particular star that humans, for most part of civilization, were also interested in, but for different purposes – The Polaris aka the Pole Star. We need to align our imaging equipment to this star so that we can track the sky and take longer exposure images. The polar alignment was done, and I locked in my first target to image – the North American Nebula in the Cygnus Constellation. Did I imagine it would be a cakewalk? No. But the weather was much harsher than what I thought would be. It was very windy and cold. With all the warm clothes on, I was feeling the cold. Operating the laptop, camera, connecting the wires with the glove on, it was an overwhelming first hour. There was a voice that kept telling me maybe go back in and get some warmth and come back when winds die down. But what if the winds don’t die, and when they do, what if clouds blanket the sky? It was too small a window of time for clear skies and you had to make the best of it.

Milkyway from Hanle Village

I acquired about an hour of data before the clouds would roll back in for the rest of the night. I was unsure of the quality of the data acquired but nevertheless what I will remember of those 2 or 3 hours of clear skies is this: the full extent of the arm of the milkyway galaxy stretching across the sky from one end to another. What a sight! That just answered the earlier question of what could Hanle offer? Despite another disappointing night for AP, this memory would stick on.

A small lake in Hanle Village
Grazing meadows and blue skies in Hanle Village
Ruddy Shelducks
Tibetian Wild Ass

Now that 3 out of 5 nights were washed out, except for those brief 3 hours, we had become numb to what might come in the next 2 nights. But I still had hope. The next morning one group went to the most famed umling la pass which is located close to 19000 ft. I chose not to join them, instead I joined in with Sudhash, Suresh, Shashi and Jagan to drive around Hanle to look for birds. We spent 3 hours there and we saw a lot of birds and beautiful landscapes. I will rather let the pictures speak for themselves. We came back for lunch, and I rested for a good 4 hours till about 6 pm. I needed this sleep, as I knew if the skies clear up for the night I need the energy to stay through the night even at the cost of missing a visit umling la pass. It would turn out to be the best decision I made.

The North American and Pelican Nebula
The Heart and Soul Nebula
The Witchhead Nebula

The 4th night was the night for all of us. For what we had all come for. Right from dusk all the way to dawn the sky remained crystal clear with very occasional clouds. The sky was in full glory throughout the night. I acquired 3 targets that night: The North American Nebula, The Witch Head Nebula and The Heart and Soul Nebula. I also recorded wide angle shots of milkyway galaxy band. And I distinctly remember this walk with Subhendhu after dinner. We walked back to IIA from homestay. No lights around, open sparkling skies, and we walked with our dim red head torches to guide us one step at a time. A walk to remember.

The Elusive Zodiacal Light

And at around 4 AM in the morning, I could hear Shashi calling out my name and asking to check for the famous elusive zodiacal light. The light from the sun scattered off by the interplanetary dust. I could see this zodiacal light extend upwards and meet the milkyway galaxy band. The temperature was sub zero at -4 degrees, and I had borrowed hand warmers from Zeeshan and Jagan, which kept my hands warm enough to function.

While my equipment was acquiring data, I got to see some wonderful objects through 25 x 100 binoculars of Jagan like the sculptor galaxy, and the triangulum galaxy through 12 inch dob of Sudhash. I wish I could have seen more, but next time. We would often go back to the IIA guesthouse to get some warmth before venturing out. We had some nice discussions at the time. Suresh would ask questions that would lead to discussions. There were card games. Of course there were some disappointments as well as in Vishwa’s case, whose equipment failed on him in the cold weather and he couldn’t acquire data. But very kind of him to share his inputs and insights to other APers like me. It was 5 am, and we were walking back to the homestay for a good day’s sleep.

The team with the banner next to MACE telescope

I woke up 6 hours later for lunch. Post lunch the plan was to take lots of group pictures with various telescopes along with the official banner of the star party. Naveen was clicking with his Canon 6d, and Snehith was capturing the moments using his drone. It was fun and memorable taking group pictures. Then we headed to the HCT on the hilltop to take another group picture there, and of course we were there for another dream moment: To image HCT and The Milkyway together. Sudhash had sought permission to stay there till around 9 pm or so for us to record this, provided the skies were clear. And the SKIES WERE CLEAR. All of us were ready with the frame and settings, and we recorded for about 90 minutes. We were also greeted by a big green fireball meteor that Nihal has beautifully captured. Nihal and his team with Zeeshan and Abhimanyu who wore this Martian costume and shot a scripted video with HCT and Milkyway in the frame was fun to watch.

HCT and The Milkyway
Since it was a hilltop, one can get to see a 360 degree view of the valley below. That view of the milkyway galaxy band stretching 180 degrees across the sky is what dreams are made of I guess. My fascination with how the sky would look before the artificial lights flooded the planet lay right in front of my eyes. It was an ecstatic feeling. Can’t describe precisely how it felt. I was lost in the skies, among the stars. I would just go back and sleep for the rest of the night, as I was tired and I needed the energy to pack up everything the next day and had to start by 10 AM.
Milkyway as imaged from Leh
We all packed up, the entire group left except for Sudhash who would stay for a day more. We stayed in Leh city limits close to the airport in a fancy looking resort with a good view of the mountains. I was surprised to see the milkyway with naked eye almost halfway up the sky. I wasn’t expecting that level of visibility within city limits. I recorded milkyway from Leh as well. My friend Ganesh and his daughter Aishwarya, setup their gears again in Leh and acquired some good quality data of fee targets that they had originally planned.  Except the Coimbatore trio, everybody had their flights the next day, and had to say goodbye until next time. We stayed there an extra night, and we had to repack for air cargo and ship it. There was a confusion in the sending the air cargo, but am not getting into the details of it, but I would like to thank Mr. Dorje Angchuk, Mr. Suman, Mr. Tsewang Dorjai and Sudhash for coordinating and helping us get our cargo back safely to Kochi airport. Ganesh and I drove to Kochi to collect it, and that day we came back with our equipment back home, marked the official end to our trip.
My sincere thanks every single team member and friend, who helped each other one occasion or the other, one way or the other – it was such a lovely group. A deserving mention to Sudash who made all the arrangements for a smooth experience, and to Vishwa, Keerthi and Subhankar who gave us valuable inputs based on their previous experiences at Hanle. And of course, my sincere thanks to Mr. Dorje Angchuk, the chief engineer in charge of Indian Astronomical Observatory in Hanle, who made this entire star party possible under the official capacity of The Indian Institute of Astrophysics.
Goodbye Hanle, until 2023!

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