Monday, 7 September 2020

Backyard birding in Chennai gets a fillip at this time of the year

 Author: Ravi Kailas

The migratory race of the Orange-headed Thrush that Chennai plays host to in winters

A couple of days ago, looking up towards the sky, around dusk, to see (mostly) flying foxes, parakeets, egrets and pigeons, from a mid-city Chennai terrace, a falcon, an unusual sight in these parts, zipped across overhead, snatched a small bird  (or bat), with its talons, (spectacularly) mid-flight, before disappearing from view. The event lasted less than a minute, and it was too dark to make out any other features, except to make out that a bird was a mid to large sized Falconid. Could it have been a Peregrine Falcon, resident or migratory race, both of which have been recorded from within Chennai? Or a rarer passage migrant (Amur Falcon for example)? While still early for bulk of the winter visiting and passage migrant raptors, passerines and shore birds in Chennai, early September marks the beginning of the season, when the city's urban gardens and wetlands, plays host to an interesting variety of avian visitors from afar. 

Indian Pitta are always a delight to see, and often quite vocal at dawn and dusk

While in Chennai, I am especially partial to the convenience of backyard birding, weighing the impressive, 'winter' diversity of birdlife in the grasslands and wetlands around the city (or should have been, but now bang in the middle of it, thanks to the sharks (no offence to the nice kind that inhabit oceans), who manage to convert water into land), against the traffic and pollution, that one needs to grapple with, on the way to anywhere that resembles a pleasantish natural area, within a couple of hours from the city. Besides, some of my best birding moments have occurred while glancing groggily at a backyard green-space, with a newspaper and a morning cup of filter coffee for company, when 'something unusual' (hard to explain this any other way) would hop into the periphery of my vision. These high intensity birding efforts (yes, because I would then have to frantically rush inside to find a pair of binoculars before the bird rushes off)  have produced, not only the regular winter migrants like the Indian Pitta, Orange-headed Thrush, Brown Shrike, Blyth's Reed Warbler and Asian Brown Flycatcher but also relative rarities like Brown-breasted Flycatcher, Green Leaf Warbler, Forest Wagtail, Blue-throated Blue Flycatcher and even a Slaty-legged Crake! Pittas, always nice to see, and Asian Brown Flycatcher, tend to stick around, if they find the buffet of insects etc to their liking that is, but the least expected and longest staying visitor, turned out to be the rare (in these parts), Slaty-legged Crake, happily spending a couple of months, skulking in the low bushes along the compound wall! It also helps that as a family of nature enthusiasts, it is not just my groggy, peripheral vision that picks up these shapes, and it has often been my father's in which such happy matters have come to light. While not in the (at least mine) backyard, but rather at the superb Huddleston Gardens of Chennai's Theosophical Society, one of the city's finest green spaces along the Adyar Estuary, I have come across rarities like Chestnut-winged Cuckoo and Ashy Minivet, lifers at that time and birds I have not seen anywhere else since. Although I have not been as lucky, others have also recorded seasonal visitors like the lovely Black Baza, Indian Blue Robin, the rarely seen Malayan Night Heron and Tickell's Thrush, among others, in the city's green spaces. 

Slaty-legged Crake, the unexpected rarity that delighted us armchair birders for weeks

Blue-throated Blue Flycatcher are passage migrants through Chennai

All told, this is the time of the year to look out for, look forward to, the dash of variety that these avian visitors provide, few of them here to stay put in the green spaces around Chennai, but many on their long haul from the Himalayan region to the jungles of Sri Lanka (the same species also head to the mountains of south India, but I understand the migratory path is different for those populations). 

Monday, 24 August 2020

GSO Star Tracker Telescope, my ('minimalist') night-sky gazing set-up: An Overview

Author: Ravi Kailas

The rather imposing size of the set-up, belies the simplicity of the Dobsonian telescope design 

For observing the night sky, I primarily use a GSO Star Tracker, a 8" Dobsonian telescope (a type of telescope, which despite its bulk, is the best value for money for light gathering ability), manufactured by GSO (Guan Sheng Optical, a Taiwanese Manufacturer). I purchased this from Tejaraj & Sons, Mumbai, a reputed dealer, probably the only one of its kind in India, of astronomy related equipment, relying on their advice to buy this model (as against similar from well known brands like Orion), for its better value for money among identical optics in the alternatives.  

The telescope comes supplied with with 2 eyepieces - a 9mm 1.25" and a 30mm 2", among a handful of other accessories (see below). I also have a Pentax AMC XW 14mm, 1.25", which works for both wildlife watching with a spotting scope, as well as for astronomy with this telescope. I find both the Pentax and the 30mm 2" eyepieces provide very satisfactory views, with ample eye-relief, field of view and a wholesome image circle, but the Pentax is significantly more refined with excellent edge to edge sharpness. The 9mm is not as satisfactory to look through, with a poor eye-relief and a small, incomplete image circle, but centre sharpness and resolution is adequate and provides good views of difficult subjects like Epsilon Lyrae. The eye-pieces give me magnifications of 133x (9mm), 40x (30mm) and 85x (14mm) (magnifications are calculated by dividing the focal length of the telescope, in this case 1200mm, with the focal length of the eyepiece). Higher magnifications are better for planets, features on the moon, globular clusters and double stars and wider views for diffuse subjects like nebulae, star clusters, star fields and the like. 

Sadly, however, the light gathering ability of this telescope, with its 8" aperture (a size, on the cusp of what are called 'light buckets', for the amount of light that they allow inside), is wasted on Chennai's skies, where some of the more diffuse subjects are often hidden by light and atmospheric pollution. Also, the highly magnified perspective offered by a telescope, might not be ideal to observe large (apparent size) celestial objects, such as the Pleiades Star Cluster, and one might be better off using lower power optics typical in Binoculars (please see article for binocular basics as relevant to nature observation) to enjoy a more satisfactory view of these. 

Sometimes, all it takes is a good pair of binoculars

Other supplied accessories:

The telescope (tube, mirrors, front cover and focussing mechanism) is supplied with:

- guide scope, 
- AA Battery Holder to run the cooling fan, 
- Wooden base, which works surprisingly smoothly (at least until it was left out in overnight rain) to move the telescope around to point at the desired portion of the sky, 
- an adapter for 1.25" eyepieces, 
- a Neutral Density Filter (decreases brightness and increases contrast - essential for lunar features to 'pop' into view) that screws onto to the 1.25" eyepiece for observing the moon
- A 35mm extension tube 
- some collimation tools
- An Allen Key, size as appropriate for assembling the equipment
- A silica gel holder, which can be used in place of the eyepiece, while stored

There is a bit of DIY to get things up and running, much of the work to do with putting the base together. The instructions are fairly clear though, and if I remember correctly, I could get everything functional within 2 hrs (altogether another matter that I had to wait quite a while longer for clear skies - Murphy's Law governing new equipment, the law's effects, inevitably, directly proportional to the enthusiasm with which you want to try the equipment out!). 

Mobility & Ease of Use

This telescope is large, as all Dobsonians tend to be. As such it is best suited for situations where clear skies are close at hand (unlike in my case, where I live under extremely polluted city skies - but I was sorely tempted by the cost-to-brightness ration of the set-up, just in case I managed to move it to a dark sky location for any decent length of time). However, if you envisage moving your device around a lot, then a Newtonian or Refractor telescope could be a wiser investment. 

One reason Dobsonians tend to be cheaper are due to their simplistic design. Most (if not all) are manually operated, with no tracking or star location aids. For a relative newbie, when I invested in this telescope (my first one), I found the necessity to manually train the scope on the celestial object of choice, to be an educative experience, allowing me to 'learn the sky' in the process, but a tracking feature would have been nice all the same. Initially, the base was excellent for manipulating the scope, but later some play developed in the altitude adjustment, that has made it harder to hold highly magnified views in place.  

A slight nuisance of the Dobsonian design (or any reflector telescope) is the need to collimate its components, before first use, and at intervals determined by how much 'travelling' the telescope has done. This is essentially a technique to ensure that all the optical and mechanical parts of the device are proper are properly aligned. I collimated the mirrors just once, given the limited travel my telescope has done (between my home interiors and the terrace on a good day or night), and this was easy enough to perform on this telescope, with which I had only ever enjoyed the optics so far. 

For Astrophotography

Given the lack of mechanised tracking ability, this telescope has a fairly limited use for long exposure astrophotography. However, with the right adapters and filters, the set-up should be adequate, albeit with limitations, for images of our Moon and Sun. I have only ever tried photographing the Moon, by awkwardly manipulating my phone camera on the eye-piece, for modest results, not commensurate with the effort required to time the shutter release, in that fleeting, unpredictable moment that a decent image appears on the screen!

For some knowhow on astrophotography, and it's nuances, from yours truly, please follow links for basics and deep sky subjects, respectively. 

Friday, 14 August 2020

Himalayan Serow and Brown Wood Owl at Pangot: Report

Author: Ravi Kailas

Dates: 7th to 9th June 2019

Himalayan Marten, among the highlight mammals of the trip
Himalayan Marten, among the highlight mammals of the trip

A brief summer visit to Pangot (2000m) a tiny village surrounded by temperate broad-leaved forest in the Kumaon Himalayas, was productive for a sighting of the uncommonly seen Himalayan Serow, as well Himalayan Goral and Himalayan Marten, among commoner mammals. Birdlife was a modest representation of Himalayan species, both summer visitors and residents, with Brown Wood Owl, Hill Partridge, Himalayan Prinia, Mountain Hawk Eagle and Wedge-tailed Green Pigeon among the highlights in the broader landscape, encompassing a elevational gradient and associated habitat. The trip coincided with the mad summer rush of tourists to the mountains, and Naini Tal, the gateway to Pangot, is among closest targets for the teeming millions residing in the bubbling cauldron that Delhi becomes at this time of the year - not ideal conditions if you are looking for rare wildlife in an idyllic Himalayan forest!

Detailed Report

Day 1: A large part of the day was spent exiting the typically hazy surroundings of Delhi, the inevitable traffic snarls, various highway bottlenecks, caused by a combination of repair works and fellow motorists, a (un?)healthy proportion heading to the hills, most trying to defy the laws of physics (it is a given that the laws of traffic are meaningless in this part of the world), by trying to squeeze through invisible gaps, invariably, through oncoming traffic, and finally arriving at the foothills around Kaladhungi at 1730, a good 3hrs after the ETA at the time of the departure (0930). Some casual birding, in the mixed forest on the cusp of the ascent, was good for Greater Yellownape, Grey-capped Pygmy Woodpecker and Large Hawk Cuckoo among others. While Great Slaty Woodpecker are known from Sal forest locations around the foothills, we did not attempt a sighting, given the delayed progress already. The rest of the snaking up the hills through a line of very slow moving traffic, along, mostly, disturbed habitat, was not especially productive, bar for commoner birds. Relative peace and quiet after the going past Naini Tal, onto the hour or so long drive on the forest road leading to Pangot. Despite the promising hour (1915 at the time of entering the forest road) for a safari, on a road known for a good population of Leopard, the rest of the evening proved unproductive for any wildlife on this windy evening. 

Day 2: Break of dawn on the 30km or so forest route from Pangot to Kunjakharak was satisfying for a variety of birdlife, including a various of Turdus and Zoothera thrushes, Chestnut-headed Laughingthrush, Rufous-bellied Woodpecker, Mountain Hawk Eagle, Rufous-bellied Niltava and Khalij Pheasant among others.While a sheer, grassy, hill slope, en-route is known for relatively regular sightings Cheer Pheasant, we did not find any, in the 30 minutes or so we stopped here, also enjoying a lovely view of the Corbett NP landscape below. While looking for C(c)heer though, we were granted our wishes, sort of, with sightings of several Himalayan Goral, popping into view from against background  of grassy hill slopes that they blend into rather too well. There were also Himalayan Langur and Indian Munjtac, among the modest selection of mammals that showed up in the 5 hr plus excursion. 

Look closely and you will see a Himalayan Goral blending into this grassy slope at Cheer Point

Scaly Thrush

Chestnut-headed Laughingthrush

Heading back on the road towards Naini Tal, we hopped off our vehicle at the superbly located Kilbury FRH and ambled back on the 5 KM road to Pangot. A walk along a  path, that soon, blended into a jungle stream, was a worthwhile sidebar, not just for the serene stillness, the interplay of tiny dots of light on the dark interiors of the temperate broad-leaved forest, but also for a Himalayan Marten disappearing up a rocky slope - but not before showing the requisite curiosity that their kind are known for. A pair of nesting Whiskered Yuhina and a noisy troop of Rhesus Macaque, with a faint apprehension of a potential black bear encounter accompanying the viewers, the guide having had an experience in this very location in the past, completed the picture in this idyllic setting. The walk back to Pangot, on the forest road, produced White-throated Laughingthrush, Black Eagle, Black-headed Jay, Black-faced Warbler and Maroon Oriole among the highlights

Temperate Broad-leaved forestscape

Black-faced Warbler

Whiskered Yuhina

The rules of plying the forest road at night are a little hazy, but since the road is not closed for traffic after dark, we used the opportunity the traverse the 30Km stretch from Pangot to Kunjakharak, known for frequent leopard sightings, but we were also interested in possibilities for Leopard Cat and Himalayan Palm Civet (perhaps not optimal habitat for the latter two though). In the 3 hr or so effort, culminating at midnight, none of these targets showed, however we did see the uncommon Himalayan Serow on the slopes of the aptly named Cheer Point (please see AM activity for context). Indian Munjtac and Sambar Deer were ubiquitous, and Wild Pig, foraging in a garbage dump near Pangot, completed the mammal list, while a large owl (Brown Wood?), that disappeared from a roadside tree into the thickets, was the only bird on show. 

Brown Wood Owl

Day  3
: A pre-dawn start towards Tangdi, a settlement of horsemen and stables, on a vegetated slope close to Naini Tal, specifically hoping for good views of Hill Partridge, but also other skulkers that are known to pop outside the underbrush onto the paths, probably attracted by the insect rich ecosystem that thrive on dung and their donors. The hour or so drive, while at a promising hour for mammals, only produced Himalayan Goral, contemplating a slope downhill, as we arrived, but rather more decisive about its movements, just as I picked up my camera. It was meagre pickings at Tangdi, for birds, with only Rusty-cheeked Scimitar Babbler and Himalayan Shrike Babbler adding to the trip list, but we did hear Hill Partridge throughout the walk along the bridle path. However, we were luckier with sighting the bird, noisily feeding behind underbrush, near the Kilbury FRH, on the way back to Pangot. This little viewing was accompanied by persistent alarm calls of the munjtac - the closest we felt to sighting a Leopard on this trip. Later, a tip from a fellow birder, brought us to a roadside tree, where a duo of Brown Wood Owl were roosting, looking at us, sometimes one-eyed, but always disinterestedly sleepy-eyed, as we tried to find good angle for a picture, without unduly disturbing their reverie.

Indian Munjtac

White-throated Laughingthrush

Himalayan Goral

That (warm) evening, we descended, a few hundred metres, towards a mountain village (Buggar?), to look for birds that thrive in the forest edge-agriculture landscape of the region. A mix of colourful denizens, such as Blue-capped Rock Thrush, Slaty-headed Parakeet and Crimson Sunbird entertained, but the highlights were the range restricted Himalayan Prinia and Wedge-tailed Green Pigeon. Driving back towards Pangot at dusk, an Indian Hare and a family of Khalij Pheasant among the last observations on this brief visit to Pangot.  

Crimson Sunbird

Slaty-headed Parakeet

Himalayan Prinia

Wedge-tailed Green Pigeon

Logistics Etc

All arrangements, including taxi from Delhi, a bird guide at Pangot and stay at the Jungle Lore Birding Lodge were made by Asian Adventures.

Jungle Lore Birding Lodge, a very popular stopover for birders from around the world, is a mix  comfortably furnished, spacious cabins in a quaint corner of the Pangot village, its grounds, rustically unkempt as perfectly suited for nature enthusiasts. Unfortunately, the (considerably noisy, night revelling) spillover crowds from Nainital, had made their way over here (and have for some years now, considering the number of lodges and campsites that have popped up in Pangot over the last ten years), scuppering, I suspect, a more fruitful effort for mammals.  My naturalist guide, Deepak, was good company, and  knowledgable about the natural history intricacies of the region. 

List of Mammals Seen

Himalayan Langur Semnopithecus ajax
Rhesus Macaque Macaca mulatta
Himalayan Marten Martes flavigula
Himalayan Serow Capricornis thar
Himalayan Goral Naemorhedus goral
Indian Munjtac Muntiacus muntjak
Sambar Deer Cervus unicolor
Wild Pig Sus scrofa
Indian Hare Lepus nigricollis

Please see ebird links below for bird observations from the trip: 

List 1 (Day 2 AM)

List 2 (Day 2 PM)

List 3 (Day 3 AM)

List 4 (Day 3 PM)

Monday, 27 July 2020

Comet Neowise from a Chennai terrace part 2

Author: Ravi Kailas (

After making a post on my first sighting of Comet Neowise, on Thursday, 23rd July, the sky was clear enough (relatively speaking, but not before a typically dramatic (see video below), July evening cloud build-up in the western sky, threatening a black-out) for another attempt at imaging the comet, on Friday, 24th July. 

While, in the earlier post, I might have suggested that this comet is comparable to Hale-Bopp, that visited three decades ago, I understand that it is barely (although higher in the sky) a naked eye object of late, with a visual magnitude of over 7 (unlike in early July, while it was, reputedly, much brighter in morning sky) and its fuzzy spread of light (unlike pin-point sources like stars), makes it all the more difficult to spot without visual aids. Light polluted city skies, as in Chennai, with veil of high clouds, and additional light from the first quarter moon, do not particularly help matters either and it required a bit of effort, looking through binoculars in the section of the sky, west of Ursa Major, before I can locate a faint greenish-blue blob, with vestiges of a tail. Fortunately these conditions stayed, more or less the same, through a prolonged imaging effort (for an hour or so from about 1920), and I managed a series of multiple images, with a combination of settings (see table below and associated images), all untracked, with an m43 camera (Olympus O-MD E-M5II) and a M. Zuiko 40-150 2.8 lens. 

Image no.     Focal Length                     Settings
1                    150mm                                     ISO 1250 2.5s f 2.8 Stack of 21 Images
2                    150mm                                     ISO 3200 1.6s f 2.8 Stack of 21 images
3                    150mm                                     ISO 1600 3.2s f 2.8 Stack of 18 Images
4                    150 mm                             ISO 2000 1.6s f 2.8 Stack of 21 Images

While the results, after much post processing (alignment and stacking to start with) with Lightroom 6.0 and Nebulosity 4.0, were a tad better at eking out some of the faint tail, than my first effort, the resultant images were riddled with unattractive artefacts from the pp effort of pushing the image data to reveal the fainter details of the comet. But, I will let you decide, whether or what you like, or otherwise, from the images below!

Image 1

Image 2

Image 3

Image 4

I suspect that this will be among the last of my imaging efforts of Comet Neowise, with the brightening moon promising to interfere with what little is visible of the comet as it is, while it is still predicted to remain in our view until the end of the month, after which the comet will disappear, on its travels to other parts of the solar system, for over 6000 years. 

Wednesday, 22 July 2020

Comet Neowise (and others stories) from a Chennai terrace

Author: Ravi Kailas

The barely discernible Comet Neowise in the only image I managed to capture, before the clouds took over

An unusually (relatively speaking) clear July sky over Chennai (13N 80 E) yesterday evening (21/07/2020), prompted me to drag my behemoth 8" Dobsonian telescope onto the terrace, to enjoy the spectacles that the summer night sky, with the star rich regions of the Milky Way, its numerous star clusters, star clouds and Nebulae, (potentially!) visible in the early hours of the night. Saturn (just past opposition, incidentally) and Jupiter, also rise just after sunset and plonk (not exactly) themselves at a nice height to view, at an 'earthly' time of the night. While fiddling around with pointing the telescope at Saturn, with a temperamental base (that rotates smoothly for 358 degrees and tightens up for the other 2, invariably, just in the part of the sky that I want to look) and guide scope, I happened to turn around and look at the section of the barely exposed (from my terrace, given a tall building that blocks a chunk of the sky in this direction) northwest section of the sky, through my 10x42 binoculars, to find a faint, fuzzy bluish-green source of light. Suitably interested, I clicked a hasty picture with a 40-150 2.8 lens on an M43 camera, at 150mm (300mm full frame equivalent) for 5 seconds @f2.8, ISO 200 (I would have pushed this to 3200, if I had a bit of time to think) which showed up the faint vestiges of a tail (light pollution and high clouds in that section of the sky, the culprits, I suspect, apart from likely imperfect focus, given the hasty set-up), confirming that it was indeed a comet and my Star Walk 2 app, confirmed that it was Neowise. While it was a far cry from the brilliant pictures circulating online, and, I am given to believe, views through the binoculars, that this comet (a naked eye object, the likes of which was last seen when Comet Hale-Bopp graced our skies in the 90s) has delighted watchers of the northern skies with, over the last month or so,  it was nice to see  it all the same, in Chennai's almost perennially hazy skies (I did try earlier as well, in a brief window of somewhat clear sky, around sunset, a couple of days ago but no go). Hoping to get an opportunity at a better view though! The good news, that the Comet is projected to stay longer  above the horizon in the early part of the night, for the next few days at least. Just for reference, I saw the comet at around 19.40, a few degrees below and southwest of Ursa Major's pointer star, but as for all celestial objects, its position is dynamic and if you are seeking an audience with this tailed wonder, you would be well advised to look at its current position, rising/setting times, with a night-sky app. 

However the night was not just about the comet, and I had good views of the double double (Epsilon Lyrae - a star system that appears as a single star to the naked eye, but reveals itself, with the appropriate magnification/resolution, as a double star, and look closer, with a companion each - a great test for your optics and eyes!) in Lyra, Alpha (and one of its companion stars) and Beta Centauri, shining bright, low in the south, the crisply clear summer triangle formed by Vega, Deneb and Altair, the stunning contrast between a golden-yellow star and its bluish-white companion of Albireo, the vast Scorpius Constellation and its nuances, the dense collection of stars that make up Sagittarius Star Cloud, the intricate pattern formed by the bright stars of the Ptolemy Cluster, the tightly knit Butterfly Cluster, Jupiter and Saturn - all told, a satisfactory night of sky-gazing, by Chennai standards, which had both good seeing for the planets and transparency for the fainter objects, albeit marred by high clouds in some parts and fast moving, lower clouds, obscuring views on occasion. 

On another note, the Covid related lockdown made me appreciate the views from the terrace, the little green space around my apartment for its surprisingly engrossing natural riches. A Blue-throated Blue Flycatcher on a fruiting Peepal, and the associated buzz of insect and bird activity, early in the lockdown period, piqued my interest to look closer - a space that I had paid very little attention to before now. I observed the changing of the seasons, more closely than before, the shedding of leaves of the deciduous trees, followed by the flowering/fruiting season, the magnet for bees that the flowers of the Indian Ash Tree is, the number of animals - birds, squirrels, bats, and even a couple of Bonnet Macaques - all, keen competition for my mom, a fellow mango enthusiast - the variety of insects, that gorge on Mango, both full and half eaten, the abundance of insect life following a few rain showers, praying mantis, wasps and beetles, the diversity of ants and spiders, the fruiting bodies of fungus that popped up after the thunderstorms, the large colony of Flying Foxes that would head south over our terrace at dusk, the Bark and House Geckos that spend the day sheltered behind the cool shade of the fencing, only to show themselves in the open, when the temperature was just right (one would assume), the winged termites that hover around artificial light, and one evening, a precursor to the biggest rain of the season, feasted on by an insectivorous bat, that picked one after another of these hapless creatures from around a light burning in the balcony, a colony of naughty termites that made our front entrance door their larder, the dramatic, convection induced clouds that fill the western horizon, on numerous evenings, after the onset of the summer monsoons ... just some of the sights that kept the naturalist in me sated, in the few square metres within a bustling city that is home. 

Friday, 19 June 2020

Binoculars for nature-watchers: an introductory guide

Authors: Ravi Kailas & Ganesh KR (

The sheer pleasure of observing nature through a pair of fine binoculars is pretty near unparalleled, a feeling akin to the extension of your own vision, only more vivid and magnified several fold, placing you in the midst of the occupants of the distant scene. Binoculars have been indispensable tools for nature watchers (we can’t think of walking into a natural area without a pair around our necks, unless it hangs off a harness!), birdwatchers especially, for decades now. However, with the advent of digital photography, the recent generation of nature observers have reduced binoculars to mere tools of identification trading off the pleasure of the view through them against their extra weight/cost and relying instead on the ‘lifeless’ digital image for their appreciation of scene (or for identifying the subject). This article, while making a case for including binoculars in your packing list (not at the cost of a camera, necessarily!) for your next nature outing, is intended as a guide to selecting a pair, given the confounding number of variables to take into account, just in case you are (wisely) considering a purchase already and don’t know where to start. 


Criteria that (should) matter

In a nutshell




Types of Binoculars

Field/Angle of View
Minimum Focussing Distance
Chromatic Aberration 


Size and Weight

Weatherproofing/Build Quality


Availability and Service


Basic Types
    -Porro Prism
    -Roof Prism
Specialist Binoculars
    -Range Finder
    -Image Stabilised
    -Individual and                Hands Free                   Focus         




Our eyes are remarkably versatile organs, capable of discerning subtleties of light that other optical aids will struggle to match. Ideally, binoculars should enhance (and not subdue) the refinement of our natural vision. Introducing below some of the important optical criteria to look for in binoculars 




Simply put, the number of times closer that a particular object, located at a given distance, appears, while looking through binoculars in comparison to the naked eye. In binoculars one would see this denoted as a number (for example “10”) followed by an “x”. If, for example, it says 10x, then the object will appear 10 times nearer than it would with the naked eye, all else being equal.  


While absolute magnification is one of the key reasons one would buy a pair of binoculars, it does come with a host of trade-offs (such as brightness, stability and field of view - discussed in relevant sections in the article). For nature enthusiasts observing Earthly denizens, one could look at anywhere between 7x to 10x for handheld use (the higher the magnification the more difficult to get a steady image). Typically, for larger mammals and even birds in forested habitats (where trees limit the distance of clear line of sight), lower magnification (up to 8x) will be desirable. For subjects like shorebirds/waterfowl, one should ideally choose higher magnification (10x is a good starting point). If you are an astronomy enthusiast, you would be happier with 10x to 12x for handheld use (but other factors such as brightness and stability will also come into the picture). What you eventually choose, however, should be based on your primary interests as above, but 8x upto 10x tend to be great all-rounders. 

Details on Magnification (8x), Objective Size (42mm) and Angle of View (8.3°) as seen on the focussing wheel



Possibly the most significant attribute for nature watchers. All else being equal, the limit to your binocular’s brightness is the of the size (denoted as a number, measured in mm, following the magnification) of the objective lenses (see image below), which determines the absolute amount of light that can be gathered by the device), divided by magnification. For example, if you are using a 10x50mm binoculars (10 times magnification and 50mm objective lens size), then this number is 5mm, which is the aperture, also called exit pupil (see second image below), through which the light from the binoculars enters yours eyes. One key factor to consider here is that the maximum dilation of the human pupil, which is around 8mm. As such any exit pupil larger than 8mm for example, while not unnecessary (as it results in a more wholesome viewing circle), does not add any additional brightness to the view. Brightness in binoculars is also determined by quality of the glass, lens coatings* etc, about which the author writing this bit of text is not bright enough to discuss in-depth, except that generally, there is a direct relationship between price and such stellar qualities that determine the ability of the bins to eke out the living daylight out of any light. 

Showing the exit pupil, in this case with a diameter of 4.2mm, of a 10x42mm binoculars

Inevitably, nature-watchers will be faced with situations where light is a limiting factor. The main trade-offs to accessing more (magnified versions of light) are price, size/weight and magnification. Generally, for forest viewing it would be great to have a minimum exit pupil of 4mm (so 8x32 or 10x40 can be starting point), for those inevitable dawn/dusk/flashlight observation efforts, looking at owls, wild cats etc. If you are out looking for shorebirds for example, you might prefer to go with higher magnification at the cost of losing some brightness, since light is unlikely to be a limiting factor (however low contrast in flat grey conditions will be). For astronomy, please go with as bright as you possibly can (and you might want to be able to mount it on a tripod – so look for that option when you are buying for this purpose). All else being equal, brighter binoculars are inevitably bulkier (and heavier), given brightness is limited by the size of the objectives – a significant consideration for nature-watchers, who sometimes have to hike miles/long hours, and generally prefer, like most of the non-nature-watching members of the species, a life minus pains in the neck etc.  Once again ideal all-rounders tend fall somewhere in the middle, and 8x32 to 10x42 seem to be the best compromise between magnification and brightness for nature-watchers. 


Field/Angle of View


A related attribute to magnification is the field/angle of view, which is essentially how wide you can see through the binoculars (expressed as width or an angle) at a given distance. 


Generally a wider view is desirable for nature watchers - for example while observing fast moving subjects, like birds, or if you like to put the subject in the context of its wider environment - and most ‘good’ binoculars will provide an adequate field of view starting at around 6. However, lower end binoculars (even with identical magnification and objective lens specs) will often provide a ‘tunnel’ like view (rather than an encompassing, large image circle), of less than desirable coverage - a circumstance where the subtle differences in field/angle of view of competing binoculars, can be a significant variable for your purchase decision. 


Minimum Focusing Distance


A significant variable for those looking to focus up-close (less than 10ft are normally considered close-focusing). Those interested in butterflies, moths, dragonflies and the like will appreciate a close focusing ability of their binoculars. 


Other (optical) considerations


The optical considerations for above can be easily researched (for a purchase decision) from the specifications, which should tell all, by and large. However, the attributes below, will be best appreciated if you actually had a pair in hand (hopefully, one would be lucky enough to field-test or at least store test, these characteristics, before buying)




A key attribute where a clear, blur free image results in an enjoyable, strain free viewing experience. However, this goes beyond mere pleasure, as identification of subjects, with the aid of binoculars, is often a basic requirement for nature-watchers.  Another aspect to consider here is the centre to ‘edge’ sharpness, which is essentially how the sharpness varies from the centre (where it is sharpest, normally) of the image circle as you move away from It towards to circumference of the image. 




These are very important criteria, especially in challenging lighting conditions, for example while looking at dull coloured waders in ‘grey’ conditions, to eke out the faint details further subdued in poor lighting conditions or trying to notice finer details of a faint celestial object. Different binoculars also tend to have a background colour bias, from cool to warm, but these tend to be less obvious in better quality optics (which tend towards ideally neutral). 


Chromatic Aberration


An optical artefact that results in unnatural colour fringing around the subject, especially when viewed against the light. This can be glaringly distracting when you are looking to appreciate the finer details of the subject. Almost all binoculars have some at least, in the severest of lighting conditions, but high-quality binoculars control this coloured view better. 


*Many of the above-mentioned optical attributes are dependent on the quality of the optics and positively enhanced by lens/prism coatings, which reduce reflection of light off the lenses, thus improving the quantum/quality of light effectively reaching the final view, from the multiple layers of glass that make up a pair of binoculars. The type of coatings used can significantly alter the optical characteristics of binoculars – another basis for comparison when choosing binoculars within a similar price/specs range.






The optimal distance from the eyes to the eyepiece, where the full image circle is still retained without ‘effort’. This is especially relevant for eye-glass wearers since the minimum distance from eyepiece to eyes, is greater than while looking with the naked eyes. Generally, however, due to the quirks of optical engineering, greater eye-relief (where a broader range of the optimal distance is built in) normally results in a smaller field of view. 


Size and Weight 


An important, physical criteria, since nature-watchers often spend hours on end outdoors and would appreciate a fine balance between bulk/weight they lug around and the optical qualities of their binoculars. All else being equal, higher-powered, large aperture binoculars will be bulkier/heavier, and one has to decide, based on their needs, how far down this rung they would like to descend, for their specific purpose. Another consideration here is the type of binoculars  – Porro prism binoculars are generally bulkier for a given specification than roof prism binoculars, but also tend to be priced lower, all else being equal (to add to the already confounding purchase decision)


Once again ideal all-rounders tend fall somewhere in the middle, and 8x32 to 10x42 seem to be the best compromise between magnification/brightness and size/weight as relevant to a broad spectrum of nature-watchers


Weatherproofing/Build Quality


The ability of binoculars to withstand rain (and all associated elements of moisture), dust and a few tumbles on slushy ground (or even hard rock) is critically important for nature-watchers (especially the terrestrially fixated kind). Accidents due to impact/moisture can render your binoculars unusable when you are in the field, while you are typically miles away from anywhere where you can rectify the situation. It would be wise to pay a little more for these attributes, which will likely result in a longer lasting (resulting in lower average cost of ownership overtime) and happier relationship with your binoculars.  

The 'built like a tank' Swarovski 10x42 SLC. This pair has survived several interactions with rocks and hard places, and come out unscathed 






Price is the obvious economic consideration and limits your choices to within a range of your budget. However, generally speaking (although the gap is narrowing), the more you pay for it, the better the quality of the binoculars – and as binoculars are potentially long-serving companions (low obsolescence), you might also want to consider buying a product at a higher price level which could end up with your cost of ownership being lower over time (unless you are the type the misplaces items more than an average person does or have a tendency to get mugged for your belongings in forests etc.).


Warranty/customer service normally goes hand-in-hand with price and some of the higher-end binoculars manufacturers provide outstanding warranty terms (such as no-fault warranty, valid at least for several years, even lifetime), which should pretty much allow you to bash about your binoculars in a fit of rage and the manufacturer will still repair/replace them free of cost), and, customer service (we have had splendid experiences, especially with Svarowski Optik, as also with Zeiss and Nikon). This also feeds back into the cost of ownership over time.  


Availability and Service


While one might sit on a remote pacific island and drool at prospect of owning binoculars that catch their fancy on the (frustratingly unreliable) internet, ogling at pictures and reviews online, the chances of getting their hands on one are pretty remote. Living in a big city in India, as we do, prospects to own binoculars of your choice are pretty good (at least, they were, pre-Covid), but most models that are sold in the US or Western Europe are not available here off-the-shelf (so no chance of getting your hands on most, to test, before buying one). You could still have them imported, if you can justify the price of shipping and hideous import duties (that is, in case, you cant slip it past a sleepy customs via someone visiting from where the bins are sold)

Ok, now you have what you want in your hands. But what if something goes wrong and you want to get it repaired (regardless of warranty and on that note, warranty terms can be country specific). This is where it gets even tougher, since most of the proficient service centres are located only in their main markets (so if you live the US or Western Europe, you are generally ok). At the very least, it would help if the brand has a service centre in your place of residence, saving you typically expensive shipping costs and other customs related paperwork, to have repairs done. Having said the above, good quality binoculars seldom need any attention (unless you are unlucky and drop them awkwardly or you end up with a pair that has a manufacturing defect). 

Types of Binoculars 

In addition to the above criteria, it would also be useful to know about types of binoculars, broadly, that are available as well as some specialised versions of them: 


Basic Types 

There are two basic types of binoculars, depending on how the prism is placed within each barrel. Prisms are an essential element in binoculars to correct the orientation of the images that reach our eyes (which would otherwise appear upside down). 


Porro Prism: In Porro prism binoculars the prisms are offset from the lens elements.  

The 8x32 Nikon Superior E - note how far apart the barrels are, as typical of Porro prisms 

Roof Prism: In these binoculars, a predominant type among modern versions, the the prisms are placed in line with the other lens elements, enabling a streamlined form. 

The streamlined form of roof prism binoculars (in this case a 10x42 Zeiss Victory T-FL)

All else being equal, Porro prism binocular assembly allows for a wider field of view (however, with greater limitations placed on eye-relief) and greater depth-of-field, but also results in greater bulk than roof prism binoculars. Porro prisms are also easier to assemble and consequently, are usually cheaper than roof prism binoculars of similar specifications. 

Specialist binoculars

Range Finder: Range finders have the ability to measure the distance between the subject and the binoculars - useful for research scientists and the like with such specialised requirements

Image Stabilised: These, typically bulky, binoculars, come with an inbuilt image stabilisation, negating the limitations of higher magnification for handheld use. Those using binoculars predominantly for Star-gazing and/or pelagic birding/whale-watching from boats on choppy waters will appreciate this feature.

Individual Focus/Hands Free Focus: As against the traditional centre focus options in the majority of the binoculars, some come with the ability to focus for each eye (individual focus, for high precision - useful for astronomy, but not at all for terrestrial viewing, where subjects are often on the move), and, some which focus by tracking where your eyes focus (hands free focus)

Marine: Purpose built binoculars, often with emphasis on build attributes that can survive sustained exposure to corrosive sea-spray. It might help to know that many of these models can also float on water. Marine bins can be very useful for whale and birdwatchers, who spend of lot of time looking at shorebirds or in pursuit of pelagic species. 


The pairs we own/have owned........




I was fortunate to have access to binoculars for nature-viewing during my childhood, thanks to my father, who both introduced me to the wonderful world of wildlife appreciation on our annual holidays to Mudumalai and Kabini (sanctuaries in south India), and also shared his Nikon bins (that’s as much detail as I remember of the hardware) on those trips – an early insight into the wonderful world of nature through binoculars. Later, during my early field research days (as a student of conservation biology), I bought myself a pair of Nikon Monarchs (one of the no frills models in the series), primarily for its waterproofing (I was counting crocodiles from boats that were prone to capsize those days, and as you can see, lived to tell the tale, albeit of binoculars). All I can recall now was that they served me well (but something about the build quality was not as appealing). There is a hazy recollection of one or two cheap pairs before this, but the sum of what I can remember from those ownership experiences was me having to squint through perpetually misaligned optics. 


Then came the first real ‘pair’ of binoculars that I had the absolute pleasure to look through – an aged and well used (objectives considerably scratched), built-like-a-tank, Swarovski 10x42 SLC. Despite all that evident abuse, what followed was among the most memorable years of nature observation, thanks in large part to these superb glasses – a full (encompassing), bright, sharp view matched with the solid (survived monsoons, butterfingers, slush and hard rock on countless occasions) grippy (great for my large hands) body and smooth focusing wheel. Aside from the optics and build quality I have a special affinity for the brand thanks to their superb customer service. When I was a graduate student in the US I made a sensible decision to mail the pair to Swarovski’s Repair US Centre for service, expecting a considerable charge for their effort. Instead I opened my mail, one (fine, as it turned out) day, to find a brand new rubber housing, eye-cups and (generously padded) neck-strap on them, all this done free of charge ((even though I bought it used, with no record of original ownership!)


As a family of wildlife enthusiasts, it was not viable to sustain our collective enthusiasm to simultaneously look through the Swarovski and having been used to premium optics, it was difficult to go back to economy class. But then again, a spartan student budget (a (un?)healthy proportion of which was inevitably spent on libations and pizza), was a definite limiting factor for owning fine optics. The internet came to the rescue, and after reading (much better) binocular guides than this, I settled on a 8x32 Nikon Superior E – optically as good as, even surpassing, some of the so called  ‘Alpha’ binoculars (usually models from Zeiss, Leica, Swarovski), but at a third of the price! Till date, this was the best pair of binoculars I have had the pleasure of looking through – a crisp, clear, wide view, with bright, vibrant colours and the subjects popping out of the background, 3D like (among the upsides of Porro prism binoculars). The one big minus in the viewing ergonomics was that I had to manipulate the binoculars to a very particular angle on my spectacles to appreciate the entire image circle (this was much easier to achieve without the glasses though and I eventually mastered using the bins even with the glasses on). The binoculars were compact, but also fit nicely in my large hands, had a solid metal casing giving it a well-built feel and the focusing was smooth and responsive, yet tactile.  What it lacked though was close focusing ability and weatherproofing (a big notch on the minus for nature enthusiasts). Build quality issues were evident also, in the flimsy rubber eyecups, and, also when bits would come loose within the barrels (I suspect those were bits of sealant which were not suitable for the heat and humidity of the field conditions where I frequented). While the excellent customer service (not as good as Swarovski) in the US were kind enough to repair or even replace the binocs free of charge (!), this happened so often (I think the 4th time I sent back the binos for the same issue) that they replaced it with a new 8x42 Nikon Monarch HG! (They had stopped manufacturing the Superior E’s, unfortunately, sometime between when I bought it in 2006 and 2018, when Nikon USA sent back the Monarch as a replacement). 


The Nikon Monarch HG is a classic example of a modern, premium roof prism binoculars and does everything very well – almost as well as binoculars which cost twice as much. The image is full (with good edge to edge sharpness), very wide (with an impressive 8.3° angle of view) clear and bright, with good contrast and natural colours. These bins are also light weight, fit great on my large hands, focusses close-up, has ample eye relief and is weatherproof. While I cannot comment on the build quality, with no (thankfully) real life incidents to test this attribute (it does feel a little flimsier than the alphas though), I did find that the body was more easily worn than its pricier big brothers. Optically, perhaps the one drawback is to do with noticeable colour fringing under challenging (backlit) conditions (despite the use of ED glass) – another aspect that the very top-end binoculars often excel at controlling. While I have not done a side-by-side comparison, I found these binoculars more than adequate in low light - an ‘as good as it gets’ attribute of a naturalist’s binoculars. A very worthy all-rounder and easily the best value for money (although, technically I did not buy them!) proposition among all the binoculars that I have used. 


Somewhere between the transformation of the Nikon Superior E to Monarch HG our family of nature enthusiasts was growing ever larger and I wanted to invest in another pair of Alpha Binoculars. I would have gone for the Swarovski EL’s, given my splendid ownership experience with the heavily used SLC. However, one day, at a Bird Fair – which had stalls of innumerable binocular manufactures showing off their wares, with a lake full of waterfowl to test the optics, enough to make an enthusiast's weak knees go weaker, I happened to have the pleasure of looking through a pair of 8x32 Zeiss Victory FL. The fabulously bright, encompassing view was very special indeed (to put things in perspective this experience was in the middle of looking through some of the world’s (other) top binoculars, so some pretty great basis for comparison). The quest in earnest for this model in the used market (otherwise well outside my budget), proved fruitless for a couple of months until I came across a listing for Zeiss 10x42 Victory T FL, at a price I could just about justify. Not exactly the model that I wanted, but online reviews seemed to suggest that these were just as good, and I emptied my wallet for a pair. As it turned out, there was lots to love about these bins, from the crisp, clear, contrasty, bright, full and sharp view, with great natural colours, in all manner of lighting conditions and how effortless it was to look through them (easy to achieve the full image circle and no eye-strain whatsoever during extended use) and its buttery smooth focusing. They also felt reasonably well built (not as solid as the Swarovski SLC), quite light weight for its size and fit great on my large hands. However, I could not discern that ‘special view’ that I enjoyed through the 8x32 Victory FLs. There were, however, some issues with seemingly cheaper plastic used for some parts – not what one would expect in these top end binoculars. This fact unraveled when I dropped this pair gently, one evening, just a couple of feet to the floor, to ‘dent’ one of the (hitherto) extendable eye cups (jamming the movement). However, it was easy enough to fix for free through their excellent US warranty and customer service. Another time, the drop was rather more dramatic as I slipped on a jungle stream and the binoculars were flung from around my neck to come to rest on some hard rock, a few feet away from my prone body (which I discovered, while frantically looking around, with one side of my spectacles hanging just about the tip of my nose, while the other stayed put over the eye, somewhat aiding the search effort). Sadly, this resulted in breaking off the slot, another seemingly cheap bit of plastic, that that attaches the neck strap to the binoculars, making it impossible to lug around hands free (until I improvised attaching it to a harness, with the aid of high quality rubber band in place of the broken slot). Amazingly though, this drop and a subsequent one of similar magnitude, did not damage the optics in anyway, which remain stoically delightful (I am looking for some solid wood to touch just as I write this). 



(Coming soon)

Some Basics of Binocular Maintenance

Preening your binoculars regularly is essential for a happy, long-lasting relationship with them. Here are some basics:

- As cumbersome as it can be, do rid your binoculars of dust and grime that inevitably accumulates during nature-observation oriented travels. Be sure to get into the nooks and crannies of the body, with a soft cloth (damp is ideal if your bins has some weatherproofing at least, but wipe clean with dry or keep in airy place until fully dry) and cotton buds for those really difficult spaces (and believe me, there are a few). If your binoculars are waterproof, you can even rinse with water and dab dry. Do not use any soaps/alcohol/detergents in the cleaning process. 

- While cleaning lenses, you have to take special care to protect the special coatings that enhance the view through the bins. Only use soft, lint free cloth, or, a ball of cotton wool, to clean the lens surfaces, and make sure you get rid of the dust on them, by blowing and/or lightly dusting with a soft brush (made specifically for use on optics), before you start the cleaning process. Clean with a circular motion with minimal pressure. For stubborn smudges, use only lens cleaning wipes, made specifically for cameras lenses and binoculars (they come pre-moistened with chemicals that are easy on lens coatings). 

- Water/Fog Proof binoculars are typically hassle free to store (with minimal chances of fungus growing on the inside elements), however, regardless of their moisture proofing, it is best to store binoculars in a well ventilated and well lit location. If you live in extremely humid conditions you might consider storing your binoculars in a dehumidifying cabinet (where the humidity levels are controlled within the cabinet).


A glance at some binocular jargon


Eye-piece: The narrow end of the lens that one looks through the binoculars from

Objective Lens: The lenses from where lights enter the binoculars (the broad-end located opposite the eye-pieces)

Exit Pupil: The image circle formed on the eye-piece, the diameter of which is calculated by dividing the size of the objective lens by the magnification 

Angle (Field) of View: The maximum potential angle or width that you can view through your binoculars at a given distance. 

Eye Relief: The range of distances from the eye-piece to the eyes that allow for a full image circle to be observed. 

Diopter Adjustment: A feature (typically and adjustable wheel attached to the focussing wheel or around one of the eye-pieces) that allows to reconcile the differences in power between your eyes – especially relevant to those who prefer to view without eye-glasses (which adjust for this difference anyway, that is, if they were prescribed by a competent Ophthalmologist!)

Focusing Wheel: A component, typically located at the ‘bridge’ of the binoculars, which one adjusts to achieve a sharp image. 

Image Circle: The circular image as seen through the binoculars

Chromatic Aberration: Unnatural colour fringing that is especially evident while looking at a subject against the light

Rain guard: Caps that protect the eye-pieces from the elements. It is desirable to buy a one pice guard that attaches to the neck strap (if you use one), which makes it easier to use.

Shoulder Harness: A contraption (replacing the neck strap) that shifts the weight of your binoculars from your neck to your (often stronger) shoulders.

Tripod Adapter: A device which helps you connect your binoculars to a tripod. A useful ability for high powered binoculars that are difficult to hold steady by hand and especially relevant for star-gazers (in the nature-watcher scheme of things)