The Dutch Gadget

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I have just finished reading J.L. Heilbron’s biographical tome on Galileo, which though very interesting I found a difficult book and somewhat academic in style.  In 1609 Galileo became aware of a Dutch spectacle maker’s device that made distant objects appear closer.  He subsequently became known for developing the so-called ‘Dutch Gadget’ into what we now know as the refracting telescope and moreover, applying its use to understanding the Solar System with the discovery of Jupiter’s four largest moons, confirmation of the phases of Venus and the observation and analysis of sunspots; the word telescope was subsequently coined in 1611 from the Greek tele “far” and skopein “to look or see” i.e. far-seeing.  In so doing he also helped to confirm the then controversial truth of the heliocentric astronomical model, whereby the Earth and planets orbit the Sun.  Against this background it is no surprise that Galileo is today much revered by mankind and has become known as the father of observational astronomy.

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Drawn into the complexity of obtaining images of the Solar System and beyond, it is the curse of astrophotography that we inevitably neglect observing the spectacle itself.  Notwithstanding, I am sure that Galileo would understand the power and beauty of today’s astrophotography, which in its own way is producing a quantum leap in our understanding of the Universe comparable to the impact of the original application of the telescope.

This summer the Solar System will hopefully provide both good observational and astrophotography opportunities here at Fairvale Observatory: Jupiter, Saturn, Comet C/2015 V2 (Johnson), the Perseids meteor shower and the Sun – sadly though I will not witness next month’s solar eclipse which takes place mainly over North America.  During recent summer months the lack of astronomical darkness, short nights and absence of DSOs has frustratingly continued to limit potential imaging targets for my new ZWO 1600MM-Cool camera but utilising a period of good weather there have recently been a few fleeting opportunities just before dawn related to the appearance of the summer arm of the Milky Way on the eastern horizon.

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NGC 7000 The North America & Pelican Nebulae WO GT81 + modded Canon EOS 550D + FF | 30 x 120 secs @ ISO 1,600 + calibration | 19th September 2015

I first imaged the North America Nebula (NGC 7000) in 2014 and have since returned each year to image the nebula or its various parts using a DSLR camera.  Being a very large Ha-object the nebula is an ideal target for the ZWO1600MM-cool camera and I have been anxiously waiting its arrival again this year.  On this occasion, early on the morning of the summer solstice, high in the sky and 90o east the nebula was only just visible from my location, being very close to the roof-edge of my house!  Consisting of just six Ha-frames plus three OIII and SII taken just before dawn broke, the resulting image was never going to be my best but is nonetheless interesting in SHO format and quite different to previous DSLR images.

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North America Nebula in Ha-OIII Bicolour

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North America Nebula in SHO

At the other extreme, located low on the southern horizon and only briefly visible as it passed between the trees at the end of my garden is the Eagle Nebula AKA M16, home of the Pillars of Creation.  At 7-arcminutes in size and an apparent magnitude of +6.0, the nebula is at the lower end of possible for my set-up and at some 27o altitude with just 40-minutes imaging time between the trees it was a challenging target.  Notwithstanding, I’m pleased with the Ha and SHO narrowband images obtained, which quite clearly show the Pillars too.

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M16 Eagel Nebula in SHO: William Optics GT81 & ZWO1600MM- Cool & Field Flattener | 6 x 180sec Ha, x3 OIII, x3 SII Gain 300 Offset 10 + full calibration | 21st June 2017

As astronomical darkness is now slowly returning and with clear skies and weather permitting, I hope to attempt longer imaging sessions of both these and other targets during the rest if the summer and into autumn – I might even get to see M16 again as it eventually emerges from the other side of the trees!  Thanks to the development of the Dutch Gadget and modern cameras it is now possible for amateur astronomers to image such spectacular objects – I’m sure Galileo would be impressed and highly approve.

Brave New World

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In my quest to understand astronomy and in particular the big picture, I have just successfully completed another MOOC course at the University of Edinburgh on the Higgs Boson and particle physics.  From earlier studies which included the Special Theory of Relativity and the Universe, the next step was obvious: moving from the very big to the very small in order to better grasp where we might be with the elusive unified theory and I was not disappointed. An added bonus to the course was the participation of Professor Peter Higgs himself, in which he discussed how he had arrived at his conclusions and the development of subsequent matters that led to the actual discovery of the Higgs Boson at the Large Hadron Collider in Cern, Switzerland in 2012; watching and listening to him speak felt like having a personal chat with Einstein and was quite a privilege!

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A chat with Professor Peter Higgs!

Frankly I found the nature of the subject very difficult and at times bewildering but its potential impact on astronomy was finally something of an epiphany for me.  The Higgs and related items results in two profound results:

  • There was no Big Bang.
  • The existence of a multiverse, of which our Universe is but a part.

I am not sufficiently able to articulate how these conclusions are arrived at nor is this the place, but when the full content of particle theory, the Higgs, General Relativity are applied to cosmology, the aforementioned outcome is, like all good science, simple and beautiful – click here for lecture notes Higgsmooc part1  + Higgsmooc part2  and accompanying presentations 7.11_Quantum Vacuum_& Cosmology + 7.12_The HB_scalarfieldsand inflation.

I’m pleased to say there have also been other breakthroughs for me since achieving first light with the ZWO 1600MM-Cool CMOS camera.  I am still at the experimental stage and with the spectacle of the winter sky rapidly departing, suitable objects are much more limited, with the few remaining HII objects low and very far to the west of the early evening sky.  However, before the Milky Way disappeared completely I managed to obtain some useful imaging experience by targeting some old favourites.

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Passing Shots: Orion & Rosette Nebulae

Having already battled a number of issues with the new camera – basic LRGB image capture, using Astro Astronomy Tools, achieving focus, guiding, alignment, processing and post-processing – for the moment everything has come together, including some warmer nights and clear skies.  Over a few evenings I therefore undertook imaging in LRGB as well as Ha, OIII and SII, with some excellent results that augur well for the future.

The camera’s sensitivity and ability to image at short exposures enables much less imaging time than conventionally used with CCD cameras – one of the reasons I decided to purchase this camera.  In addition, shorter exposures make perfect alignment and tracking less important, though still a desirable set-up.  The downside is it produces a prodigious number of images, which leads to a somewhat challenging processing burden – but it’s worth it.

Despite my DSLR experience, CCD processing and especially post-processing, is significantly more complex.  I was surprised to find only one decent online video on LRGB processing by Rankin Studio, without which the task would have been even more difficult and taken much longer to learn – thanks David.  Ironically I have found narrowband processing easier, probably because there are just less filters and resulting image sets required, however, the restricted wavelength also provides whole new opportunities that I’ve already started to exploit.

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Orion Nebula + M43 & Running Man Nebulae in Ha: William Optics GT 81 & ZWO 1600MM-Cool + x0.80 field flattener | 15 x 180sec Gain 139 Offset 21 @ -18C & full calibration | 25th March 2017

Just before they disappear from our night sky until next winter I was fortunate to be able to image both the Horsehead and Orion nebulae, everyone’s favourites and I’m no exception.  With limited time available in the early evening sky it was only possible to capture a limited number of images before it moved outside my view in the west but even with these few images the power of the camera has already become self-evident.

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Horsehead Nebula in Ha: William Optics GT81 & ZWO 1600MM-Cool + x0.80 field flattener | 19 x 180 secs Gain 139 Offset 21 @ -18C & full calibration | 27th March 2017

Given the need to use less filters and thus less time I have started out with narrowband imaging – as a completely new medium for me that holds great promise aesthetically and scientifically, I was also keen to give it a try and on this occasion used Ha and OIII.  Having sorted an earlier problem with the EFW managing the filters is a breeze and can easily be automatically sequenced in the APT capture software.  Notwithstanding, as previously indicated image capture is really only just the start – though good data is always the key to the final image – and processing and post-processing is both complex and takes considerable time.

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Orion Nebula in bi-colour: Ha red channel + OIII green and blue channels

On this occasion the individual Ha subs are themselves very revealing, showing new details when compared with previous DSLR images.  But it is with the bi-colour image that the exciting opportunities provided by using narrowband imaging become apparent – I can see I’m going to enjoy this!  I’ve also taken the opportunity to further explore and understand the nature of these types of images and their constituent parts by manipulating the colour channels, with some startling results.

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Rosette Nebula in HOS: William Optics GT 81 & ZWO 1600MM-Cool + x0.80 Field Flattener | 15 x 180 sec Gain 300 Offset 10 Ha, OIII & SII @ -20C + calibration | 24th March 2017

Not far from M42 is another of my favourites which I’d already used to achieve First Light with this camera using Ha – the Rosette Nebula (NGC 2237, 2238, 2239, 2244 & 2246).  This time I decided to use all the narrowband filters – Ha 656nm, OIII 672nm, SII 500nm all 7nm bandpass – and subsequently experimented with processing using the Hubble Palette with stunning results.  As the name indicates, this technique was originally developed for processing images taken with the Hubble Space Telescope which put simply, uses different mixes of each narrowband filter in different processing channels e.g. Ha in the red channel, OII in green and SII in blue, for short known as HSO.

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Rosette Nebula in  SHO

The outcome of my new adventure into narrowband imaging has been nothing less than a revelation.  Like so much of my preceding astroimaging, I knew about much of it before but doing it yourself and seeing the results is both exciting and very satisfying; like Peter Higgs I feel I have entered a new world!

First Light

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If nothing else, I have learned from life – walk before you run.  I have spent the past three years trying to learn about astronomy and astrophotography using a DSLR but late last year decided it was time to raise my game.  I was reluctant to go to a CCD mono camera as it involves greater complexity and, perhaps more significantly, during the aforesaid period clear skies have been in very short supply – making long, guided exposures over protracted periods something close to impossible where I live.  However, with the recent advent of the new CMOS cameras and their rave reviews, against my better judgement I took the plunge and bought a ZWO ASI 1600MM-Cool with a matching ZWO x8 EFW and 31mm LRGB, Ha, OIII and SII filter set.

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Wow! As expected, it’s a whole new world compared to DSLR and, as well as continuing week-after-week cloud cover, I have been battling with numerous set-up and processing issues. Still, rule number one with this hobby is patience and perseverance and I’m pleased to say I have just achieved First Light with the camera.

At first I set up the camera indoors on a tripod to test the equipment and quickly found that the camera and EFW would not work together; in addition to a USB 3.0 data socket, the camera also has two useful USB 2.0 sockets which can be used to power and control other equipment.  After more than 3-weeks, much help online and a mixed response from the manufacturer, ZWO suggested I try another USB driver which they sent me and it worked – so why not supply that in the first place or ensure users are aware of the issue and provide a solution from the outset?  Whilst the actual equipment is well specced, well made and well priced compared to CCD camera – though far from cheap, I found ZWO’s web-based technical guidance and general support poor and would expect better with such expensive equipment.  In retrospect, perhaps it is not a surprise as I had a USB problem when I purchased their ZWO ASI 120MC camera, with a similar response and outcome i.e. there is a theme here, which is a pity as their equipment itself is innovative and very well made.

During brief periods between the clouds I subsequently managed to try-out the camera in order to understand focus, capture and processing. Despite prior experience with the DSLR and software, this turned out to be new territory which I am still exploring. Briefly:

Focus – With the new camera I was faced with two fundamental focusing issues:

  • Establishing the correct optical train – I want to continue using the William Optics x0.80 focal reducer with the ZWO camera, thereby increasing the speed of the scope from f5.9 to f4.72. I therefore purchased a Canon EOS adapter to use with the existing EOS convertor which has previously worked successfully with the DSLR.  Despite the apparent complexity, the resulting set-up is within 0.50mm of the optimum distance and seems to work OK – with one exception. Whilst the locking pin on the EOS adapter works i.e. it locks, there is some unacceptable lateral play, which for now I have solved with the addition of a piece of electrical tape! I’m advised this is normal for such adapters but it seems like a poor product to me if this is the case.    ZWO cam_EFW_FF_annotated (Large)
  • Operating focus – after months of battling with focus when I started out DSLR imaging, I eventually discovered the Bahtinov mask and assumed this wonderfully simple method would work just as well with the new ZWO camera; of course, after my initial trials it was apparent this wasn’t going to be the case.  Not that the mask doesn’t work but in order to achieve good focus with the smaller pixels of the ZWO ASI 1600 requires much greater accuracy, which I’m pleased to say has now been achieved by using APT’s Bahtinov Aid (based on Neils Noordhoek’s Bahtinov Grabber), so that I am now getting much better results.  However, as the focus point can change with seeing conditions and when using different filters, it is apparent that I’ll need to return to this matter again to finesse the operation, probably by using an electronic focuser.

Capture – At the heart of my philosophy is the KISS principal – Keep It Simple Stupid! When working with the DSLR I therefore only ever used the Canon EOS Utilities software for image capture – it is simple, did what I needed and worked.  Moving to a mono camera with filters, the increase in complexity is exponential and inevitably requires more sophisticated image capture software.  Judging by the experience of others Sequence Generator Pro seems to be one of the best low cost programmes that will do this job and I have purchased a copy for US$99 and the accompanying Framing and Mosaic Wizard for an additional US$39.  However, in applying the KISS principal during the early stages of getting to know and understand the new equipment and processes, for now I’m using Astro Photography Tool (APT) – something I’ve had for a while but not used before.  It is a very capable programme that manages sequencing, cooling, filter management etc. well, with excellent support from its author Ivo but importantly seems easier to use than SGP, albeit inevitably with its own idiosyncrasies.  It’s early days but so far so good.

Processing – Mono images differ in a number of fundamental ways to DSLR other than just colour, which requires a quite different approach to processing and post-processing, in particular:

  • the images are FITS not RAW;
  • mono images are taken with a variety of filters which subsequently need to be compiled.

Despite successfully working with Deep Sky Stacker (DSS) for some time, I was not aware of any changes required when processing FITS files, which are the product of the ZWO 1600 camera; useful pre-assessment of the files can be carried out using the ESA/NASA free Fits Liberator software.  As a result my first try of the Beehive Nebula based on just Luminance subs was covered in bizarre ‘green spider-like’ artefacts after stacking in DSS.  These disappeared when transferred into Photoshop but then became covered in Bayer matrix-like coloured squares!

Thanks to help from the SGL Forum it was apparent that I had failed to turn-off the FITS colour option in Settings before stacking – unchecking this and restacking immediately resulted in a half-decent image of the open star cluster.  Meanwhile, since purchasing the ZWO camera I have read and watched numerous videos on post-processing and using LRGB files available online for practice, I have been able to start experimenting with this technique prior to obtaining my own data from the new camera.  It is much more complex and I’ve got a long way to go but the experience gained from DSLR processing has nevertheless helped immensely; walk before you run pays off in the end!

And so last week I managed my first reasonable image of the Rosette Nebula (NGC 2244) using only Ha-subs, which this object has in abundance.  I consider this marks the camera’s First Light and am pleased with the result but realise there’s still much more to learn, weather permitting!

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Rosette Nebula in Ha | William Optics GT81 + ZWO ASI 1600MM-Cool & x0.80 focal reducer + guided | 15 x 180 secs + darks & bias calibration Gain 300, Offset 10 | 21st March 2017

  • This guided image is 15 x 180sec Ha-subs + darks and bias, gain 300, offset 10 + minor stretching in Photoshop. The corners – particularly the bottom right – look like there may be some vignetting in the stacked image?  I haven’t managed to achieve any decent flats yet (another story) but I assume these would help eliminate this effect? However, I am surprised as I’m using the ZWO x8 EFW with larger 31mm filters, which with the focal length of 382mm (f4.72) should not result in vignetting.
  • Clearly my experimentation is ongoing with this new technology and I particularly need to understand better what is the ‘best’ gain and offset setting for different types of objects.
  • Whilst the CMOS chip is bigger than standard CCD sensors it is still smaller than a standard DSLR and with smaller pixels too (3.80nm v 4.30nm), the result when used with the focal reducer is a 29% reduction of the field-of view from 3.34o x 2.23o to 2.65o x 2.0o, which on-screen translates to increased magnification and allows me to get at some of the galaxies which hitherto have been too small; the benefit is minor but is worth having nonetheless.

 

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From Cloudy Nights Forum – compiled by Jon Rista

All-in-all the ZWO ASI 1600mm-Cool is an excellent piece of kit that has the potential to open up new vistas for my astroimaging.  At a fundamental level it does all the basic stuff very well and the addition of cooling is a major improvement which  reduces noise still further.  I’m particularly looking forwards to experimenting with narrowband and bi-colour imaging – not least in order to keep working when the Moon’s about, unlike broadband imaging.  However, the cameras intrinsically low read noise and ability to capture fine detail using only short exposures is surely set to mark the next revolution in astrophotography and furthermore reduces the need for very precise guiding; it’s clear the other manufacturers are scrambling to catch-up with this leading edge technology.  Timing is everything in life and I’m pleased to be part of this hobby at such an exciting moment.

Arctic Antics

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The globe pictured above on the island of Vikingen marks the location of the Arctic Circle off the western Norwegian coast.  However, surprisingly the position of the Arctic Circle is not fixed – as of 28 February 2017 it was 66°33′46.6″ north of the Equator but changes depending on the Earth’s axial tilt, which itself varies within 2° over a 40,000-year period due to differing tidal forces that occur as the Moon’s  orbit changes around Earth.  The region north of the Arctic Circle is famous for the midnight sun in the summer and its corresponding 24-hour darkness during the winter months, with major implications for life itself, as well as contrasting scenery and photographic conditions unique to this hostile region.

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During the last two weeks of February, when the return of limited daylight has just begun to mark the end of winter, I travelled by ship along the entire western and northern coast of Norway close to the Russian border, spending much of the time within the Arctic Circle.  The area is famous for its beautiful scenery, in particular the fjords which typify the coastline and for time immemorial have posed a significant challenge to all seafarers passing this way.

Our ship, the Richard With, was named after the Norwegian captain who in 1893 pioneered this difficult sea passage which we took from Bergen to Kirkenes and back.  Today a fleet of 12 ships are operated by the original Norwegian company Hurtigruten on a daily basis providing ferry transport for goods, vehicles and personnel, as well as a base for tourists seeking a view of the Northern Lights – in all the ship stops at over 30 ports in each direction.

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Apart from the scenery, during the winter months the area north of the Arctic Circle is probably best known for the occurrence of the Aurora Borealis or Northern Lights (Norwegian – Nord Lys).  A view of this feature is treasured by all who see them but for astrophotographers it will be one of their ‘must do’ images to acquire.  The Aurora is caused by a solar wind originating from the Sun that consists of charged particles, which when drawn downwards at the Earth’s poles by the planet’s magnetosphere ‘excites’ atmospheric atoms which produce different coloured lights depending on the type of gas which is excited by the charged particles; a similar feature occurs around the South Pole called the Aurora Australis and is also now known to occur on Saturn and Jupiter.  The lights are mostly green in colour (ʎ 557.7 nm), sometimes red (ʎ 630 nm) or blue (428 ʎ nm) and less commonly pink, ultraviolet or yellow, depending on the altitude and type of excited gas – which is mostly either oxygen or nitrogen.  The resulting aurora takes the form of rapidly moving clouds or often curtains of light that dart across the night sky, constantly changing shape under the influence of the Earth’s magnetic field and does not disappoint when seen.

The Northern Lights are best imaged with a standard DSLR camera on a sturdy tripod, using a wide angle lens at full aperture, set at between ISO 800 to 1,600 and exposures of about 8 secs to 25 secs, depending on the brightness and quality of the light and the speed of movement of the aurora; focus and all other control needs to be operated manually for best results.  On land a tracking mount, such as a Vixen Polarie, could be used to improve sharpness but on a moving ship set-up and technique is a more difficult.

In this case exposure needs to be carefully balanced in order to account for the ships movement – forwards + up-and-down on the water – and the quality of the aurora light.  As exposures will always need to be greater than a few seconds, star trails are unavoidable and have to be dealt with in post processing as best as possible. I found imaging directly forwards or to the rear of the ship helped minimise this effect but still trails were still inevitable. Experimenting with various settings I found about 12 to 15 seconds exposure and ISO 1,600 generally worked quite well but varied depending on the sea conditions and nature of the aurora at any time.

At such high latitudes it is still very cold in February and warm head-to-feet-to-hands clothing is absolutely essential.  On this occasion, together with wind chill the temperature at the ships bow ranged from between -20oC to -30oC (that’s a minus sign!), making camera control very difficult and uncomfortable!  I tried using an intervalometer for remote shooting but as settings have to be changed frequently by hand it was not very practical; I’m sure on land it would prove much more helpful.  Furthermore, much of the time I had to hold the tripod down with some force as the wind was very severe.

Notwithstanding, I’m very pleased with the results shown below and would love to return again one day, perhaps in the summer – it is a truly different and very special part of the world – hat’s off to Richard With and all those who still sail these waters.

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Photons & Photography

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I’ve been interested in photography from a young age.  As I child I played with my parent’s Kodak box camera and, as far as I can remember, my first camera was a Kodak Brownie at the age of about nine. It’s a wonderful medium that I have now experienced for over 50-years, on land, underwater and now for astrophotography.

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My cameras

I’d like to think I know a thing or two about photography by now; underwater photography and digital astrophotography have been particularly challenging in different ways but the latter is a real eye opener that has expanded my knowledge of digital imaging significantly.  Capturing images of distant objects that can only be seen with the use of sophisticated equipment and complex processing also requires an in-depth understanding of light itself.

Having spent the first half of this year reading Einstein’s biography, I have recently started an online course at Stanford University on his ground-breaking Special Theory of Relativity.  Einstein’s many insights into the physical world are profound, which more than 100-years on still challenge most of us to understand.  Light was at the core of his famous 1905 paper, in particular it’s duality as a waveform and light quanta, or photons – defined as a quantum of electromagnetic radiation.  His concept of the photoelectric effect has enabled the development of today’s digital camera sensors and CCDs.  The core principal is the production of electrons as light shines onto a material, whereby the light (photon) knocks out an electron which can then be collected electronically – the basis of digital photography.

In September I visited Lacock Abbey in Wiltshire, initially a 13th century nunnery which is now run by the National Trust.  Today it is better known as the home of William Henry Fox Talbot (1800 – 1877) – mathematician, astronomer and archaeologist but most famously the inventor and pioneer of photography, notably developing, fixing and printing.  The window photograph below (left) was taken at Lacock Abbey in August 1835 and is recognised as being from the oldest ever camera negative produced by Fox Talbot, on the right is the same window in 2016.

In the early 19th century Thomas Wedgwood had made photograms – silhouettes of leaves and other objects – but these faded quickly. In 1827, Joseph Nicéphore de Niepce produced pictures on bitumen, and in January 1839, Louis Daguerre displayed his ‘Daguerreotypes’ – pictures on silver plates – to the French Academy of Sciences. Three weeks later, Fox Talbot reported his ‘art of photogenic drawing’ to the Royal Society, which subsequently became the de facto basis of modern film photography.

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Fox Talbot’s desk in his study at Lacock Abbey

Fox Talbot lived and worked at the Abbey for most of his life.  As well as an excellent museum, which details the history of photography and photographic processes, the house contains his rooms where he developed (no pun intended) the aforementioned inventions and is surely a ‘must do’ visit for any keen photographer.  Like many at that time he was a polymath, with notable friends and accomplices who worked in similar and other scientific fields:

Sir John Herschel – astronomer, mathematician, botanist & chemist, Gold Medal winner and founder of the Royal Astronomical Society, son of William Herschel who discovered Uranus.

Charles Babbage – mathematician, philosopher, mechanical engineer, considered “the father of the computer”;

William Whewell – leading 19th century scientist, recognised in the fields of architecture, mechanics, mineralogy, moral philosophy, astronomy, political economy, and the philosophy of science;

Sir Charles Wheatstone – physicist, inventor of stereoscopic photography, the telegraph & accordion;

Sir David Brewster – physicist specialising in optics, mathematician, astronomer & inventor of optical mineralogy and the kaleidoscope;

Peter Roget – physician, theologian, lexicographer and publisher of Roget’s Thesarus.

This particular group are now remembered by a table setting in the Abbey’s dining room, where they gathered for dinner; the mind boggles at the conversation!

Fox Talbot’s pioneering photography work preceded the early 20th century understanding of light that arose from Einstein and its more recent application in semi-conductors as camera sensors, of which I am sure he would have approved.  At that time the Universe outside of our galaxy was also unknown and he would have marvelled further at the thought of imaging other such distant galaxies such as M33 below; like photons, photography has come a long way since his death in 1877.

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M33 Triangulum Galaxy – consisting of some 40-billion stars, the photons in this image have travelled 3-million light years to reach my camera’s sensor! | WO GT81 + modded Canon EOS 550D & FF guided | 18 x 300 secs @ ISO 800 & full calibration | 22nd October 2016

It’s All Relative

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I spent the first half of this year reading Walter Isaacson’s biography of Albert Einstein, which apart from providing a fascinating insight into the man and his work, whetted my appetite to understand better the science.  Following previous success studying astronomy courses online, I set out to find a suitable programme to achieve this goal.  As a result I enrolled for Understanding Einstein: the Special Theory of Relativity run by Professor Larry Lagerstrom of Stanford University, USA, which after two months I have just completed.spacetime

The course is a good mix of qualitative and quantitative information, which at times has been quite challenging but nonetheless proved very worthwhile. The lecturer is very clear and thorough, an essential quality when dealing with this difficult and often bewildering subject.  Einstein’s paper On the Electrodynamics of Moving Bodies outlines the Special Theory and was just one of four published at about the same time in 1905 (“The Miracle Year”) which included: Brownian motion, Mass-energy equivalence (E=Mc2) and The Photoelectric Effect, the latter of which won him the Noble Prize.  At the end I now feel I understand the basics of Einstein’s ground breaking science properly, which apart from being interesting provides valuable insight and understanding of the Universe and related issues of space and time.

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During this period I have also been thinking about how to improve my astrophotography and the way forwards.  I’ll be on the learning curve for years to come and accept that there’s much I can still improve on using current equipment and processes but after more than 2-years astroimaging, mostly with a DSLR camera, I feel I have reached something of a crossroads and need to change tack in order to achieve more meaningful advances once again.  Inevitably this is likely to mean new equipment and most likely a move to LRGB / Narrowband format.  In the interim, whilst I consider the options, I have also been researching suitable capture / sequencing software, post-processing techniques and programmes.  I am concerned that this will result in another level of complexity but I think it has to be done in order to progress – watch this space.

Continuing a trend that’s been apparent for the past year, clear nights have been something of a rarity since mid-September; this is a concern if I am to pursue astrophotography to the next level.  However, high pressure was unusually dominant over Fairvale Observatory during the last days of November and cold, clear skies have provided good conditions for astronomy at last.

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Getting better – PHD2 screen 30th November 2016: DEC is good but room for improvement with the RA settings. The impact on tracking and image quality is noticeable.

Whilst I have certainly not fully mastered guiding I am now routinely using PHD2.  This in itself has probably been the major breakthrough this year, which with the aforementioned clear skies I wanted to take full advantage of.  Hidden within PHD2 I have also discovered and am now starting to experiment with the on-screen drift align routine, with reasonable results; using the gamepad for mount control and a new wireless link with my tablet computer, I can also make focus and alignment adjustments at the mount without returning to the computer each time.

As a result I have dispersed with the SynScan handset for alignment and can now completely set-up and control imaging with the computer and tablet; this is nothing short of a revolution which I am hopeful will greatly increase set-up time as well as improving control and tracking accuracy – yipee!  Even with average guiding results I am now achieving good exposures of 5-minutes or more and therefore decided to put this success to work and re-image some winter wonders over three, yes three, consecutive nights at the end of November.

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Imaging targets between 28th & 30th of November 2016 – for descriptions & previous images taken of these objects click on the following list of names: (1) M45 Pleiades (2) Barnard 33 The Horsehead Nebula & NGC 2024 Flame Nebula (3) M42 Orion Nebula (4) NGC 2244 Rosette Nebula (5) NGC 1499 California Nebula (6) IC 405 Flaming Star Nebula

The night sky at this time of the year contains many of my favourite objects, but surprisingly I had not imaged some of the chosen targets for more than a year or two and it was both enjoyable and pleasing to reacquaint myself again.  With a new perspective gained from this exercise, the progress I have made with equipment and techniques is more apparent.  Notwithstanding, it’s time to move on – everything’s relative.

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M45 Pleiades, Taurus constellation: 12 x 300 sec @ ISO 800 | 28th November 2016

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NGC 2014 Flame Nebula & Barnard 33 Horsehead Nebula, Orion constellation: 15 x 300 sec @ ISO 800 | 28th November 2016

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M42 Orion Nebula & M43 De Mairan’s Nebula, Orion constellation: 2 x 300 sec @ ISO 800 | 28th November 2016

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NGC 2244 Rosette Nebula, Perseus arm of Milky Way, Monoceros region: 21 x 300 sec @ ISO 800 | 29th November 2016

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California Nebula, Perseus constellation: 12 x 300 sec @ ISO 800 | 30th November 2016

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IC 405 & 410 nebulae: 15 x 300 @ ISO 800 | 30th November 2016

Notes: all images taken using a William Optics GT81 refractor telescope + PHD2 guiding + modded Canon 550D DSLR & x0.80 field flattner @ ISO 800 with full darks + bias + flats calibration and processed in Deep Sky Stacker & Photoshop CS2  

The future is not what it used to be

 

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If I’m honest my astrophotography has so far often been – never mind the quality feel the width!  That is to say, I have tended to chase objects – nebulae, galaxies, planets, solar – in order to learn about my equipment and the night sky as well as just have fun recording images of these distant worlds.  Nothing wrong with that is there?  It’s not that I don’t aspire to obtaining the best image possible and I have made good progress since starting out but I’ve often felt constrained by circumstances.

Although I’ve generally been happy with my images, it’s a fact that there are a number of factors that altogether make astrophotography difficult, especially here at Fairvale Observatory:

  • Poor weather & persistent cloud cover
  • The Moon
  • Buildings & trees obscure sightlines
  • Light pollution from Gatwick airport
  • Numerous aircraft passing overhead
  • Equipment problems
  • Software problems
  • Equipment and software failures
  • Equipment limitations
  • Need to assemble equipment each time
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Bad weather, frequent cloud cover, limited sightlines, aircraft trails and the inevitable monthly occurrence of the Moon limit imaging opportunities here.

Under these circumstances I usually need to grab what I can, frankly it’s a miracle I’m able to achieve anything sometimes; Met office statistics for the six-months period from September 2105 showed cloud cover was a record 68% compared with an historical average of 32% for that time of year, as a result it was unusual to be able to undertake astrophotography more than once month, if that!  Wherever possible I therefore have to target those items that I can improve easily, quickly and cheaply dealt with, which is mostly equipment.  Buoyed by renewed enthusiasm from my recent autoguiding success, I now intend to concentrate on changing some key items that I hope will eventually bring about more noticeable improvements.

sign2For a while I have been thinking about getting a larger telescope, in order to get to those faint fuzzies that are beyond the capabilities of the otherwise excellent William Optics GT81.  As usual the choice is a minefield of possibilities, each with inevitable imaging pros and cons!  I started thinking about a Ritchey Chrétien or Schmidt Cassegrain but I have really appreciated the qualities of the aforementioned WO GT81 and am now erring towards a larger refractor.  However, after further consideration I am now considering a change of priorities.

In September I was fortunate to attend a presentation on image processing by Nik Szymanek who, it has to be said, really knows his onions when it comes to astrophotography; I was intrigued and impressed to find out he also hails from my neck of the woods when I was a teenager in Essex and is an accomplished rock drummer – something I also used to meddle with in the past – what a geezer, as he would say.  The talk was very instructive and I am now ploughing my way through Nik’s fabulous book on the subject called Shooting Stars (published in magazine form by Astronomy Now).  Such personal, first-hand and relevant guidance is difficult to find in astroimaging and the book has a wealth of really practical information and useful advice that I wished I’d known sooner.  Good equipment is important but in the world of digital imaging the significance of processing cannot be overstated.  It’s a dark art alright (no pun intended) but Nik’s work has strengthened my resolve to improve my processing knowledge and I’m even more determined to raise the bar during the forthcoming winter.

20160708-shooting-stars-for-storeFollowing Nik’s talk and listening to others, the penny that has now dropped is that for the moment it’s not the telescope but the camera that needs changing.  After careful thought it’s apparent that I already have very good set-up, yes a bigger aperture would be good for those smaller fuzzies but the 81mm apochromatic refractor I already own is an outstanding telescope that still has much potential when combined with the AZ-EQ6 mount and now autoguiding.

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The addition of a modded DSLR at the beginning of last year had a significant impact on my images, especially with Ha dominant DSOs which I literally saw in a new light using this camera.  I have continued with the DSLR for a number of reasons but mainly because I am familiar with such cameras which are relatively easy to use and produce reasonable results when starting out with astrophotography.  However, listening to Nik and reading the forums and elsewhere, I have come to accept that the best way forwards should now be a CCD-type camera.  As a result I am deep in my research of CCD issues and possible cameras – this could take some time and won’t be cheap!

The operation of CCDs is quite different to a DSLR and I’m sure will involve a whole new period of pain but it’s clear that this is the best route for now if I am to significantly improve my astrophotography.  Other than the technical challenges CCD imaging presents, I am however concerned about the greater number of frames needed for LRGB + calibration and how that’s going to work with the weather restrictions and other problems I have but it’s got to be worth a try.

However, before setting out on this daunting task I first slewed the camera towards a few familiar objects just to experiment with guiding and assess the benefits it might bring to my imaging in the interim.  A spell of unusually good weather in late August – early September was too good to miss and with guiding I was able to achieve exposures of up to 8 minutes.  However, for the moment I continued to limit the number of Subs and calibration frames just to ensure I could shoot more objects in the available time, plus you never know when the next bank of cloud will roll in – old habits die hard!

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Looking at the results below demonstrates my progress when compared with earlier images but the limited number of frames and calibration has probably restricted the full benefit of what might be gained from guiding and some shots remains quite noisy. Nonetheless, I now have high hopes that the potential is within my grasp to make real progress in achieving better image quality.  I am not convinced I have yet reached a turning point but I am well positioned to navigate the tasks required to get there, which are now more clearly understood and in my sights or should that be RDF – watch this space!

M31 Andromeda Galaxy

M31 DSS2 30 sec ISO800 170814crop

WO GT81 + unmodded Canon 700D & FF| 10 x 30 secs & ISO 800 | August 2014

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WO GT 81 + modded Canon 550D + FF | 9 x 120 secs @ ISO 1,600 | 19th September 2015

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WO GT81 + modded Canon 550D & FF & PHD guiding | 10 x 300 secs @ ISO 1,600 calibration | 8th September 2016

NGC 6905 Western Veil Nebula – The Witch’s Broom

NGC 6960multiplelevelsonecontrast FINAL(Medium)

Canon 700D | 20×90 sec + darks.bias/ flats @ ISO 800

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WO GT81 + modded Canon 550D + FF & PHD guiding | 5 x 300 secs @ ISO 1,600 & calibration | 8th September 2016

NGC 6888 Crescent Nebula

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WO GT81 + modded Canon 550D + FF | 19th October 2015

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WO GT81 modded Canon 550D + FF & guiding | 10 x 300 secs @ ISO 1,600 & calibration | 11th September 2016

NGC 6992 Eastern Veil & Bat Nebula

NGC 6995 Stacked1-22 (Large)

Eastern Veil Nebula – NGC 6992 (right) & NGC 6995 (left). WO GT81 + Canon 700D & FF | 29 x 120 secs + darks/bias?flats @ ISO 1,600

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Eastern Veil Nebula (NGC 6922 & 6995): WO GT81 & modded Canon 550D + FF & guiding | 10 x 300 sec @ ISO 1,600 + darks | 11th September 2016