Monday, September 16, 2013

From Here to Eternity - An exploration of the universe through the Lens

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We had been to Great Himalayan National park which is situated in the Kullu valley of Himachal Pradesh during August 2013. Though it was a prime monsoon season, the rains were not that dominant in the hill state during the time we stayed there.

The rain and the sun were always playing the game of Hide and Seek which gave me the feeling of the unpredictable Himalayan climate.

The team consisted of (Mr. Bhaskar , Mr. Presley , Bharath , Chiru and Myself). 

 I always wanted to see the night sky in its full glory in the Himalayas, as the night sky in the city seems to be disturbed due to light pollution.

Watching the night sky was an amazing experience, as we were busy in arguing about the planets like Jupiter or Venus and even Mars too. Also connecting the stars and visualizing the constellation was equally thrilling. 
There were few meteoroids or shooting stars that passed by and the joy of seeing them booming is to be experienced.

Our experiences and adventures in the hills of GHNP will be followed by another blog. This blog is mainly about Star (Night Sky) Photography.

Here are few images that I shot during my stay in the valley.

All these images are my first attempt, and hoping to improve them in my future encounters with the night sky. Most of them are just record shots which represents the actual sight of amazement and excitement that I faced when we saw the beautiful gems hanging in the sky in the laps of the mighty Himalayas.

(Milky way shot at the Rangthar meadows in the National Park)

Star trails photography is one my favorite theme in the vast world of Photography. 

A star trail is a type of photograph that utilizes long-exposure times to capture the apparent motion of stars in the night sky due to the rotation of the Earth. A star trail photograph shows individual stars as streaks across the image, with longer exposures resulting in longer streaks. Typical exposure times for a star trail range from 15 minutes to several hours, requiring a 'bulb' setting on the camera to open the shutter for a longer period than is normal.

(Milky way and our tent)

Star trail photographs are possible because of the rotation of the Earth on its axis. The apparent motion of the stars is recorded as streaks on the film or detector. For observers in the northern hemisphere, aiming the camera towards the north creates an image with concentric circular streaks centered around the north celestial pole.

Star trail photographs can be used by astronomers to determine the quality of a location for telescope observations. Star trail observations of Polaris have been used to measure the quality of seeing in the atmosphere, and the vibrations in telescope mounting systems

Star trails have been used by professional astronomers to measure the quality of observing locations for major telescopes.

Star trails formed in the backdrop of our tent with the North star towards the left

The Milky Way is the galaxy that contains our Solar System. Its name "milky" is derived from its appearance as a dim glowing band arching across the night sky in which the naked eye cannot distinguish individual stars. The term "Milky Way" is a translation of the Classical Latin via lactea, from the Greek γαλαξίας κύκλος (pr. galaxías kýklos, "milky circle").

Milky way and the camp fire


From the Earth, the Milky Way appears like a band because its disk-shaped structure is viewed from within the Galaxy. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. In the past, astronomers thought that all of the stars in the universe were contained inside of the Milky Way.

The Milky Way is a barred spiral galaxy some 100,000–120,000 light-years in diameter which contains approximately 100–400 billion stars. It may contain at least as many planets as well. The Solar System is located within the disk, about 27,000 light-years away from the Galactic Center, on the inner edge of a spiral-shaped concentration of gas and dust called the Orion–Cygnus Arm. 

The stars in the inner ≈10,000 light-years form a bulge and one or more bars that radiate from the bulge. The very center is marked by an intense radio source named Sagittarius A* which is likely to be a supermassive black hole.

Stars and gases at a wide range of distances from the Galactic center orbit at approximately 220 kilometers per second. The constant rotation speed contradicts the laws of Keplerian dynamics and suggests that much of the mass of the Milky Way does not emit or absorb electromagnetic radiation. 

The stellar disk of the Milky Way Galaxy is approximately 100,000 ly (30 kpc) in diameter, and is, on average, about 1,000 ly (0.3 kpc) thick As a guide to the relative physical scale of the Milky Way, if it were reduced to 100 m (110 yd) in diameter, the Solar System, including the hypothesized Oort cloud, would be no more than 1 mm (0.04 in) in width, about the size of a grain of sand.
(Source : Wikipedia)

The Milky Way and the Andromeda Galaxy are a binary system of giant spiral galaxies belonging to a group of 50 closely bound galaxies known as the Local Group, itself being part of the Virgo Supercluster.

How to Photograph Star Trails ?

Firstly lets see the things you need before shooting star trails
(Going to Remote areas or forests like Himalayas or Western ghats, which is very far from the city gives a chance to get a good and clear sky)

Things needed :

1. A Digital SLR Camera (or a camera with the ability to shoot under Manual mode with Bulb Setting)
2. A Good Tripod
3. A wired shutter release with a mechanism to lock the shutter button down
4. A clear, dry night
5. Spare batteries
6. Time and Patience
7. Something to clean the lens if it becomes foggy
8. Powerful Torch
9. Off course a Clear sky with bright stars :)

Setting up the equipment : (Based on my experience)

1. Set up the camera by mounting it firmly on a tripod and compose the image accordingly.

2. Change the priority to "M" , meaning Manual and select Bulb mode.

3. Set the focus to infinity (Manual Focus), never use the auto focus since it searches(hunts) once the remote is clicked. 

4. Set the Long Exposure Noise reduction as High (On) in the camera - this reduces the noise in the image. If it is Off also, it is not a problem

5. Focus on any distant bright object and leave the focus ring unchanged.

6a. For shooting star trails :
Set the aperture to F/3.5 - F/5.6 , with ISO 400 to 800 , for less noise.

Usually you can keep the shutter open from 15 mins to 1 hour or even more depending on the situation.
So what many people do is shoot images with an interval of 1 min and stack the images using the software.

6b. For Shooting the Milky way without the formation of trails :

The same setting(Steps 1 - 5) has to be followed. 
Later, set the biggest aperture (Smallest F number like F/2.8 or F/3.5 etc ), and increase the ISO to 3200 and above if required.

I followed this rule to calculate time :
( T = 500 / F) , 
where T - time , F - Focal length 

Suppose you are using an 18 mm lens, the time can be set as 500/18 = 27.77 secs which is ~ 30 secs
Hence I gave the exposure time of 30 secs. Giving more time may lead to formation of streaks(trails) in the images.

Click the image under different setting of ISO's and compare the results as You are the best judge.

7. If you keep the shutter open for 20 mins and have your camera setting as Long exposure NR as On , then your camera won't be usable for another 20 mins after you have shot the image since it will be processing the image.

8. Always a wide angle lens such as Tokina 11-16 mm / Nikon 12-24 mm / Nikon 18-105mm (As I am a Nikon user) etc is suitable for star trails.

9. And the main thing , enjoy the moment with your eyes too :)

The Equipment I used : 

Nikon  D90 
Nikon 18-105mm F/3.5 - F/5.6 VR lens
Benro Tripod
Aputure timer remote (Intervellometer)

Thank You

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