Astrophotography (from one amateur to others) Part 1 - The Basics

Author: Ravi Kailas (ficustours@gmail.com)

The Genesis

A part of our home galaxy, close its core, captured from the trans-Himalayan cold desert region of Spiti Valley, Himachal Pradesh

Among the privileges of visiting natural areas is the potential to gaze at dark night skies and the countless pinpoints of light that fill it. On good nights, this can be a truly mesmerising experience, that touches the depths of your soul! While I have been smitten by these celestial splendours ever since I started visiting these far flung natural areas, for decades now, the curiosity to learn about, and photograph them, was a relatively recent phenomenon, coinciding with the advances in digital photography.

Particularly, my interest in astrophotography was piqued, when I watched Brian Cox's absorbing "Wonders of the the Universe", where he illustrates some mind-boggling astronomical phenomena with pictures. However, pictures of the night sky don't just satiate scientific curiosity, but capture details (and colours) not visible to the naked eye (sometimes even with aid of commercially available visual aids) - and (can) look pretty good too! It was around that time that I had a chance to test out the retro-styled, mirrorless Fuji X-100 - its compact size and somewhat wide focal length, well suited for wide-field Astrophotography. This coincided (the stars had aligned, it seemed)  with a visit to a dark sky location in the hills of south India, and at a great time of the year for cloudless skies (March). On one of those cool, star-filled nights, I set up my camera on a sturdy tripod, pointed it towards the heavens and made a series of images (intending to stitch together as a time-lapse video), and was pleased as punch, which the obviously unrefined, but the reasonably detailed out-of-camera images that resulted. This was a good six years ago. I now consider myself an intermediate level astrophotographer and am here to share some basics (much gleaned from information online, over the years) and my unique approaches/equipment set-up for the art, while by no means comprehensive, or flawless, I hope will guide others starting out or exploring new techniques, in this absorbing hobby where nature is the central subject.

Before we go any further though, there are some pervasive limiting factors, involving time and space, to observing and photographing the night sky:

The significance of dark sky locations:

Dark skies can reveal fainter objects like the Heart and Soul Nebulae, from a single, albeit tracked, long exposure. PC: Ravi Kailas

One of  the great limiting factors in astrophotography is where you choose to photograph from, related to the nature of the skies in that location. Generally, the darker the sky (sans light pollution and moonlight), the better it is for most types of astrophotography - and the further you are from light (and atmospheric) polluting city, the wider the gamut of celestial objects (including faint nebulae, globular clusters and distant starts), available for you to observe and capture in photos. Colder, drier mountain air (less haze) are also generally better suited for astrophotography, than warm and muggy conditions. Having said that, city skies can also be ok for observing and photographing brighter objects like the Moon, some planets and constellations, and of course, the Sun!

In some parts of the world, there are dedicated dark sky reserves, where the good folk recognise the importance preserving the Earth's natural rhythms of light and dark, for its citizens to experience and appreciate this intrinsic natural phenomenon and its associated splendours. In India, where I live, while we do not have dedicated dark sky reserves, there are places (still, fortunately!), often high in the hills or within/bordering nature preserves, which have some of the desirable characteristics of dark sky reserves. The most dramatic night skies I have had the privilege of photographing have been in the Trans-Himalayan region of Ladakh (above 3000m), the Himalayas of Uttarakhand (about 2500m) and to a lesser degree, in the Upper Nilgiris and High Ranges of Munnar. However, depending on where you live, relatively dark skies should be accessible closer to home (like it is for me about 3 hours from Chennai, but significantly interesting natural areas, sadly, are much further away).

A special mention to accommodations that I found particularly suited for observations and astrophotography, from my travels in India:

Hotel Stendel, Nubra Valley, Ladakh: Located in the small village of Diskit, the terrace on this hotel is ideally suited to set up your equipment to point to the skies, with the convenience of the hotel beneath your feet! And some rather dramatic scenery of mountains and cold desert to boot, typical of this magnificent region of the Trans-Himalayas.

Padma Homestay, Hanle, Ladakh: A remote location this at close to 4000m on the edge of the Tibetan Plateau. The homestay itself is spic and span and a stone's throw away from an open meadow, surrounded by magnificent snow-capped peaks and access to very dark skies. Incidentally, Hanle is home to the highest observatory in India - an additional attraction for astro enthusiasts visiting here. And there is that added attraction of the unique wildlife of the trans-Himalayas and Tibetan Plateau - Pallas's Cat, Snow Leopard, Tibetan Wolf, Tibetan Fox, various mountain ungulates, Black-necked Crane ... just a small sample of what is possible!

The scenic meadow in the vicinity of the Padma Homestay is a a great location for Astrophotography

Magpie Jungle Camp, Uttarakhand: Superbly located in a vast meadow, at 2500m, surrounded by the temperate forests of the Kedarnath Sanctuary, and the greater Himalayas looming the background. Dark night skies, great wildlife (Leopard Cat, Leopard, Himalayan Tahr, Himalayan Black Bear, Himalayan Serow among others), a top birding destination and lovely Himalayan views!

Red Hills Resort, Upper Nilgiris: An old style plantation bungalow, turned boutique hotel, bordering the montane forests of the Upper Nilgiris at 2300m plus. Dark skies and endemic wildlife of the Western Ghats.

When you go: 

When you go, is as important as where you go. Pick the appropriate Moon phase, suited for the nature of your subject. For dark nights, I personally find the waning moon more convenient (from the last quarter, leading to a couple of days after the new moon), since I prefer the early parts of the night to photograph in. You should also check sky-charts to see if the subjects that you are interested in photographing will be visible from your chosen location, when you plan to visit.

Weather can be a real spoilsport, and, as we have daily proof, generally unpredictable. For cloudless skies, then, the obvious solution is to choose locations with fewer cloudy days per annum and precipitation, which tend to be in the deserts (even here, the higher you go, generally, the better it gets) or, if that is not practically possible, pick the dry season. Generally colder, winter nights offer greater 'transparency' (better for picking out fainter stars, without atmospheric haze interfering) and in some special cases, such as for planet observation/photography, better 'seeing' (a view of the subject not marred by atmospheric turbulence), a hazy summer night maybe preferable.

What you can capture on camera, while looking up at the heavens

There are several photographic subjects/themes among the celestial wonders of the skies. Here are some I have personally experimented with, or know of otherwise:

(I will discuss some of these methods, where I have personal experience, in greater detail, in subsequent posts)

Wide-field & landscape:

Technically, this form of  astrophotography shares most in common with long-exposure, landscape photography, and indeed includes elements of the landscape in to the frame, with plenty of creative potential in composition, exposure length and use of artificial light. More below:

Milky Way: The dense star-fields surrounding the centre of the Milky Way Galaxy visible from Earth can provide a superb background to natural landscapes. With a wide focal length 28mm or less (full-frame equivalent) and exposures less than 30s (to avoid obvious trailing), it is possible to capture the dense star-fields and dust clouds of our home galaxy, in suitably dark skies. Alternatively, one could choose to more complex approach of stacking multiple, tracked Milky Way images, and merge the resultant image with the landscape in post processing.

Locations in the Southern Hemisphere are more suited for Milky Way photography (the galactic centre appears higher (and hence brighter) in the sky, the further south you go), but summer in the northern Hemisphere is pretty good as well.

Star Trails and landscapes: The streaks of light resulting from the long-exposure of the night sky - a result of the apparent changing position of stars relative to the Earth's rotation - can provide an artistic background to landscapes. If you point the camera towards the Earth's axis of rotation (for example the North Star in the northern hemisphere), you get those mesmerising streaks of light in concentric circles - the so called circular star trails.

Auroras: These ethereal atmospheric phenomenon that occur in the winters at high latitudes can make spectacular wide-field photography subjects, best captured with the a foreground of bleak frozen landscapes, contrasted with the an inky black, star-filled sky. Be warned, though, that while certain atmospheric conditions are favourable for Auroras (making short-term predictions of their occurrence relatively reliable), their occurrence is hard to predict well in advance (probably necessitating a multi-day visit, adorned in multiple layers of clothing, to optimise chances).

Equipment: A sturdy tripod and camera with creative controls for long-exposures and competent low-light sensitivity (in film cameras, this boils down to the choice of high ISO film). Preferably a remote release or an ability to delay the shutter release, if your camera allows such an option, and a lens with a wide focal length (35mm or below, full frame equivalent), with good optical qualities.

Time-lapse: 

An elegant method to represent phenomena occurring indiscernibly slowly, by accelerating it in a time compressed video (combining still images, taken at periodic intervals, into a (very) slow-frame rate video). Great to capture the passage of the night sky over hours or meteor showers, often with a landscape element in the frame.

Equipment: Similar to wide-field astrophotography, with an inclusion of an external or in built interval timer (many modern cameras have in-built interval timers and software to stitch together a video). 

Deep Sky: 

 Andromeda Galaxy, our nearest galactic neighbour, from the dark skies of the Kadarnath Wildlife Sanctuary in the Himalayas. Although a relatively easy deep-sky target to photograph, this rendering still required multiple images and plenty of post-processing. PC: Ravi Kailas

Perhaps the most technically challenging (extensive post processing of multiple, typically long exposure images, preceded by exacting equipment set-up) and requiring the most equipment, of all types of astrophotography - where the targets are the (often faint) nebulae, globular/open star clusters, and galaxies.

Equipment: Imaging tool (advanced, such as a DSLR or mirrorless equivalent, sometimes modified for especially for astrophotography (there are dedicated CCD cameras for astrophotography as well - this rabbit hole goes deep), attached to fast, high quality optics, very sturdy stabilisation aids (tripods, etc) and an automated tracker (a device that can compensate for the rotation of the Earth, allowing for long exposures of the night sky without star trailing). Cameras can be attached either to regular lenses or telescopes, with adapters, the optics of which are often better optimised to pick out these subjects.

Lunar Imaging: 

Our Earth's Moon is a great subject for anyone starting out in astrophotography - requiring minimal specialised skills or equipment, or even better (?), without having to travel for ideal conditions. However, there are so many facets to it, one can spend a lifetime capturing its changing phases, features and eclipses. My own experience is limited to pointing my DSLR/telephoto lens at it during total eclipses or contorting my smart phone camera lens on my 8" Dobsonian telescope's eye piece (for a resultant crude, albeit feature rich result). Here is an excellent article with the basics of Lunar imaging and much more.

The 'Red' Moon during a recent total eclipse. PC: Ravi Kailas

Planetary Imaging:

A technically challenging field, to capture the planets of our Solar Systems (Saturn and Jupiter are especially lovely and full of intricacies) of which I have very little direct knowledge. Here is an excellent piece that discusses the basics and a bit more.

Solar Imaging: 

Finally, a subject for which one need not burn the midnight oil for! While the sun can appear like a featureless ball of light, there are intricacies there like sun spots and flares, that can be brought out in images using a variety of techniques (often with use of appropriate filters). Then, there is the magnificent phenomenon of the eclipse and associated nuances to represent photographically.

Once again, I do not have direct experience imaging our Sun (apart from pretty sunsets) - here is a piece that throws considerable light on the subject. What I do know is, you must not look at directly or photograph the sun without specialised filters - since this can result in severe damage to your eyes/equipment.

My Equipment

Over the years, I have accumulated and churned through, quite a variety of equipment in pursuit of Astrophotography. I started off with an interest in wide-field, but concentrate mostly on Deep Sky subjects these days (at least whenever I get to travel to dark sky locations at the right time of year - not very often, unfortunately)

Below is a list of equipment - many of them complementing my interest in nature photography - that I use/have used so far:

Cameras/Lenses

Fuji X100 (Fixed Lens Mirrorless, 17mm f2.0)

Canon 6D coupled with

300mm f2.8 II
100-400mm f4-5.6 I

Olympus OMD-EM5 MKII coupled with

M.Zuiko1 17mm f1.8
M. Zuiko 12-40mm f2.8 Pro
M. Zuiko 40-150mm f2.8 Pro

At the moment, I only use the relatively compact Olympus system for Astrophotography.

Tracker

AstroTrac TT320X-AG

Stability Aids

AstroTrac TW3100 (Wedge for fine adjustments during polar alignment)
Manfrotto 055 ProB (Tripod Legs)
Manfrotto MHXPRO-BHQ2 (Ball Head)

Software

Nebulosity 4.0 (specialised for deep sky subjects)
Lightroom 6.0
Time-Lapse Assembler (for back in the days that you could not stitch timelapse videos in-camera)
StarStax (for Star Trails and more)

Others 

Vello remote shutter release for Canon DSLRs (with 3 pin)

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